/*
 * Copyright © 2008 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Keith Packard <keithp@keithp.com>
 *
 */

#include <linux/i2c.h>
#include <linux/slab.h>
#include "drmP.h"
#include "drm.h"
#include "drm_crtc.h"
#include "drm_crtc_helper.h"
#include "intel_drv.h"
#include "i915_drm.h"
#include "i915_drv.h"
#include "drm_dp_helper.h"


#define DP_LINK_STATUS_SIZE     6
#define DP_LINK_CHECK_TIMEOUT   (10 * 1000)

#define DP_LINK_CONFIGURATION_SIZE      9

struct intel_dp {
        struct intel_encoder base;
        uint32_t output_reg;
        uint32_t DP;
        uint8_t  link_configuration[DP_LINK_CONFIGURATION_SIZE];
        bool has_audio;
        int force_audio;
        uint32_t color_range;
        int dpms_mode;
        uint8_t link_bw;
        uint8_t lane_count;
        uint8_t dpcd[8];
        struct i2c_adapter adapter;
        struct i2c_algo_dp_aux_data algo;
        bool is_pch_edp;
        uint8_t train_set[4];
        uint8_t link_status[DP_LINK_STATUS_SIZE];
};

/**
 * is_edp - is the given port attached to an eDP panel (either CPU or PCH)
 * @intel_dp: DP struct
 *
 * If a CPU or PCH DP output is attached to an eDP panel, this function
 * will return true, and false otherwise.
 */
static bool is_edp(struct intel_dp *intel_dp)
{
        return intel_dp->base.type == INTEL_OUTPUT_EDP;
}

/**
 * is_pch_edp - is the port on the PCH and attached to an eDP panel?
 * @intel_dp: DP struct
 *
 * Returns true if the given DP struct corresponds to a PCH DP port attached
 * to an eDP panel, false otherwise.  Helpful for determining whether we
 * may need FDI resources for a given DP output or not.
 */
static bool is_pch_edp(struct intel_dp *intel_dp)
{
        return intel_dp->is_pch_edp;
}

static struct intel_dp *enc_to_intel_dp(struct drm_encoder *encoder)
{
        return container_of(encoder, struct intel_dp, base.base);
}

static struct intel_dp *intel_attached_dp(struct drm_connector *connector)
{
        return container_of(intel_attached_encoder(connector),
                            struct intel_dp, base);
}

/**
 * intel_encoder_is_pch_edp - is the given encoder a PCH attached eDP?
 * @encoder: DRM encoder
 *
 * Return true if @encoder corresponds to a PCH attached eDP panel.  Needed
 * by intel_display.c.
 */
bool intel_encoder_is_pch_edp(struct drm_encoder *encoder)
{
        struct intel_dp *intel_dp;

        if (!encoder)
                return false;

        intel_dp = enc_to_intel_dp(encoder);

        return is_pch_edp(intel_dp);
}

static void intel_dp_start_link_train(struct intel_dp *intel_dp);
static void intel_dp_complete_link_train(struct intel_dp *intel_dp);
static void intel_dp_link_down(struct intel_dp *intel_dp);

void
intel_edp_link_config (struct intel_encoder *intel_encoder,
                       int *lane_num, int *link_bw)
{
        struct intel_dp *intel_dp = container_of(intel_encoder, struct intel_dp, base);

        *lane_num = intel_dp->lane_count;
        if (intel_dp->link_bw == DP_LINK_BW_1_62)
                *link_bw = 162000;
        else if (intel_dp->link_bw == DP_LINK_BW_2_7)
                *link_bw = 270000;
}

static int
intel_dp_max_lane_count(struct intel_dp *intel_dp)
{
        int max_lane_count = 4;

        if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11) {
                max_lane_count = intel_dp->dpcd[DP_MAX_LANE_COUNT] & 0x1f;
                switch (max_lane_count) {
                case 1: case 2: case 4:
                        break;
                default:
                        max_lane_count = 4;
                }
        }
        return max_lane_count;
}

static int
intel_dp_max_link_bw(struct intel_dp *intel_dp)
{
        int max_link_bw = intel_dp->dpcd[DP_MAX_LINK_RATE];

        switch (max_link_bw) {
        case DP_LINK_BW_1_62:
        case DP_LINK_BW_2_7:
                break;
        default:
                max_link_bw = DP_LINK_BW_1_62;
                break;
        }
        return max_link_bw;
}

static int
intel_dp_link_clock(uint8_t link_bw)
{
        if (link_bw == DP_LINK_BW_2_7)
                return 270000;
        else
                return 162000;
}

/* I think this is a fiction */
static int
intel_dp_link_required(struct drm_device *dev, struct intel_dp *intel_dp, int pixel_clock)
{
        struct drm_crtc *crtc = intel_dp->base.base.crtc;
        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
        int bpp = 24;

        if (intel_crtc)
                bpp = intel_crtc->bpp;

        return (pixel_clock * bpp + 7) / 8;
}

static int
intel_dp_max_data_rate(int max_link_clock, int max_lanes)
{
        return (max_link_clock * max_lanes * 8) / 10;
}

static int
intel_dp_mode_valid(struct drm_connector *connector,
                    struct drm_display_mode *mode)
{
        struct intel_dp *intel_dp = intel_attached_dp(connector);
        struct drm_device *dev = connector->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        int max_link_clock = intel_dp_link_clock(intel_dp_max_link_bw(intel_dp));
        int max_lanes = intel_dp_max_lane_count(intel_dp);

        if (is_edp(intel_dp) && dev_priv->panel_fixed_mode) {
                if (mode->hdisplay > dev_priv->panel_fixed_mode->hdisplay)
                        return MODE_PANEL;

                if (mode->vdisplay > dev_priv->panel_fixed_mode->vdisplay)
                        return MODE_PANEL;
        }

        /* only refuse the mode on non eDP since we have seen some weird eDP panels
           which are outside spec tolerances but somehow work by magic */
        if (!is_edp(intel_dp) &&
            (intel_dp_link_required(connector->dev, intel_dp, mode->clock)
             > intel_dp_max_data_rate(max_link_clock, max_lanes)))
                return MODE_CLOCK_HIGH;

        if (mode->clock < 10000)
                return MODE_CLOCK_LOW;

        return MODE_OK;
}

static uint32_t
pack_aux(uint8_t *src, int src_bytes)
{
        int     i;
        uint32_t v = 0;

        if (src_bytes > 4)
                src_bytes = 4;
        for (i = 0; i < src_bytes; i++)
                v |= ((uint32_t) src[i]) << ((3-i) * 8);
        return v;
}

static void
unpack_aux(uint32_t src, uint8_t *dst, int dst_bytes)
{
        int i;
        if (dst_bytes > 4)
                dst_bytes = 4;
        for (i = 0; i < dst_bytes; i++)
                dst[i] = src >> ((3-i) * 8);
}

/* hrawclock is 1/4 the FSB frequency */
static int
intel_hrawclk(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t clkcfg;

        clkcfg = I915_READ(CLKCFG);
        switch (clkcfg & CLKCFG_FSB_MASK) {
        case CLKCFG_FSB_400:
                return 100;
        case CLKCFG_FSB_533:
                return 133;
        case CLKCFG_FSB_667:
                return 166;
        case CLKCFG_FSB_800:
                return 200;
        case CLKCFG_FSB_1067:
                return 266;
        case CLKCFG_FSB_1333:
                return 333;
        /* these two are just a guess; one of them might be right */
        case CLKCFG_FSB_1600:
        case CLKCFG_FSB_1600_ALT:
                return 400;
        default:
                return 133;
        }
}

static int
intel_dp_aux_ch(struct intel_dp *intel_dp,
                uint8_t *send, int send_bytes,
                uint8_t *recv, int recv_size)
{
        uint32_t output_reg = intel_dp->output_reg;
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t ch_ctl = output_reg + 0x10;
        uint32_t ch_data = ch_ctl + 4;
        int i;
        int recv_bytes;
        uint32_t status;
        uint32_t aux_clock_divider;
        int try, precharge;

        /* The clock divider is based off the hrawclk,
         * and would like to run at 2MHz. So, take the
         * hrawclk value and divide by 2 and use that
         *
         * Note that PCH attached eDP panels should use a 125MHz input
         * clock divider.
         */
        if (is_edp(intel_dp) && !is_pch_edp(intel_dp)) {
                if (IS_GEN6(dev))
                        aux_clock_divider = 200; /* SNB eDP input clock at 400Mhz */
                else
                        aux_clock_divider = 225; /* eDP input clock at 450Mhz */
        } else if (HAS_PCH_SPLIT(dev))
                aux_clock_divider = 62; /* IRL input clock fixed at 125Mhz */
        else
                aux_clock_divider = intel_hrawclk(dev) / 2;

        if (IS_GEN6(dev))
                precharge = 3;
        else
                precharge = 5;

        /* Try to wait for any previous AUX channel activity */
        for (try = 0; try < 3; try++) {
                status = I915_READ(ch_ctl);
                if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
                        break;
                msleep(1);
        }

        if (try == 3) {
                WARN(1, "dp_aux_ch not started status 0x%08x\n",
                     I915_READ(ch_ctl));
                return -EBUSY;
        }

        /* Must try at least 3 times according to DP spec */
        for (try = 0; try < 5; try++) {
                /* Load the send data into the aux channel data registers */
                for (i = 0; i < send_bytes; i += 4)
                        I915_WRITE(ch_data + i,
                                   pack_aux(send + i, send_bytes - i));
        
                /* Send the command and wait for it to complete */
                I915_WRITE(ch_ctl,
                           DP_AUX_CH_CTL_SEND_BUSY |
                           DP_AUX_CH_CTL_TIME_OUT_400us |
                           (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
                           (precharge << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) |
                           (aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT) |
                           DP_AUX_CH_CTL_DONE |
                           DP_AUX_CH_CTL_TIME_OUT_ERROR |
                           DP_AUX_CH_CTL_RECEIVE_ERROR);
                for (;;) {
                        status = I915_READ(ch_ctl);
                        if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
                                break;
                        udelay(100);
                }
        
                /* Clear done status and any errors */
                I915_WRITE(ch_ctl,
                           status |
                           DP_AUX_CH_CTL_DONE |
                           DP_AUX_CH_CTL_TIME_OUT_ERROR |
                           DP_AUX_CH_CTL_RECEIVE_ERROR);
                if (status & DP_AUX_CH_CTL_DONE)
                        break;
        }

        if ((status & DP_AUX_CH_CTL_DONE) == 0) {
                DRM_ERROR("dp_aux_ch not done status 0x%08x\n", status);
                return -EBUSY;
        }

        /* Check for timeout or receive error.
         * Timeouts occur when the sink is not connected
         */
        if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) {
                DRM_ERROR("dp_aux_ch receive error status 0x%08x\n", status);
                return -EIO;
        }

        /* Timeouts occur when the device isn't connected, so they're
         * "normal" -- don't fill the kernel log with these */
        if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR) {
                DRM_DEBUG_KMS("dp_aux_ch timeout status 0x%08x\n", status);
                return -ETIMEDOUT;
        }

        /* Unload any bytes sent back from the other side */
        recv_bytes = ((status & DP_AUX_CH_CTL_MESSAGE_SIZE_MASK) >>
                      DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT);
        if (recv_bytes > recv_size)
                recv_bytes = recv_size;
        
        for (i = 0; i < recv_bytes; i += 4)
                unpack_aux(I915_READ(ch_data + i),
                           recv + i, recv_bytes - i);

        return recv_bytes;
}

/* Write data to the aux channel in native mode */
static int
intel_dp_aux_native_write(struct intel_dp *intel_dp,
                          uint16_t address, uint8_t *send, int send_bytes)
{
        int ret;
        uint8_t msg[20];
        int msg_bytes;
        uint8_t ack;

        if (send_bytes > 16)
                return -1;
        msg[0] = AUX_NATIVE_WRITE << 4;
        msg[1] = address >> 8;
        msg[2] = address & 0xff;
        msg[3] = send_bytes - 1;
        memcpy(&msg[4], send, send_bytes);
        msg_bytes = send_bytes + 4;
        for (;;) {
                ret = intel_dp_aux_ch(intel_dp, msg, msg_bytes, &ack, 1);
                if (ret < 0)
                        return ret;
                if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK)
                        break;
                else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
                        udelay(100);
                else
                        return -EIO;
        }
        return send_bytes;
}

/* Write a single byte to the aux channel in native mode */
static int
intel_dp_aux_native_write_1(struct intel_dp *intel_dp,
                            uint16_t address, uint8_t byte)
{
        return intel_dp_aux_native_write(intel_dp, address, &byte, 1);
}

/* read bytes from a native aux channel */
static int
intel_dp_aux_native_read(struct intel_dp *intel_dp,
                         uint16_t address, uint8_t *recv, int recv_bytes)
{
        uint8_t msg[4];
        int msg_bytes;
        uint8_t reply[20];
        int reply_bytes;
        uint8_t ack;
        int ret;

        msg[0] = AUX_NATIVE_READ << 4;
        msg[1] = address >> 8;
        msg[2] = address & 0xff;
        msg[3] = recv_bytes - 1;

        msg_bytes = 4;
        reply_bytes = recv_bytes + 1;

        for (;;) {
                ret = intel_dp_aux_ch(intel_dp, msg, msg_bytes,
                                      reply, reply_bytes);
                if (ret == 0)
                        return -EPROTO;
                if (ret < 0)
                        return ret;
                ack = reply[0];
                if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK) {
                        memcpy(recv, reply + 1, ret - 1);
                        return ret - 1;
                }
                else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
                        udelay(100);
                else
                        return -EIO;
        }
}

static int
intel_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
                    uint8_t write_byte, uint8_t *read_byte)
{
        struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
        struct intel_dp *intel_dp = container_of(adapter,
                                                struct intel_dp,
                                                adapter);
        uint16_t address = algo_data->address;
        uint8_t msg[5];
        uint8_t reply[2];
        unsigned retry;
        int msg_bytes;
        int reply_bytes;
        int ret;

        /* Set up the command byte */
        if (mode & MODE_I2C_READ)
                msg[0] = AUX_I2C_READ << 4;
        else
                msg[0] = AUX_I2C_WRITE << 4;

        if (!(mode & MODE_I2C_STOP))
                msg[0] |= AUX_I2C_MOT << 4;

        msg[1] = address >> 8;
        msg[2] = address;

        switch (mode) {
        case MODE_I2C_WRITE:
                msg[3] = 0;
                msg[4] = write_byte;
                msg_bytes = 5;
                reply_bytes = 1;
                break;
        case MODE_I2C_READ:
                msg[3] = 0;
                msg_bytes = 4;
                reply_bytes = 2;
                break;
        default:
                msg_bytes = 3;
                reply_bytes = 1;
                break;
        }

        for (retry = 0; retry < 5; retry++) {
                ret = intel_dp_aux_ch(intel_dp,
                                      msg, msg_bytes,
                                      reply, reply_bytes);
                if (ret < 0) {
                        DRM_DEBUG_KMS("aux_ch failed %d\n", ret);
                        return ret;
                }

                switch (reply[0] & AUX_NATIVE_REPLY_MASK) {
                case AUX_NATIVE_REPLY_ACK:
                        /* I2C-over-AUX Reply field is only valid
                         * when paired with AUX ACK.
                         */
                        break;
                case AUX_NATIVE_REPLY_NACK:
                        DRM_DEBUG_KMS("aux_ch native nack\n");
                        return -EREMOTEIO;
                case AUX_NATIVE_REPLY_DEFER:
                        udelay(100);
                        continue;
                default:
                        DRM_ERROR("aux_ch invalid native reply 0x%02x\n",
                                  reply[0]);
                        return -EREMOTEIO;
                }

                switch (reply[0] & AUX_I2C_REPLY_MASK) {
                case AUX_I2C_REPLY_ACK:
                        if (mode == MODE_I2C_READ) {
                                *read_byte = reply[1];
                        }
                        return reply_bytes - 1;
                case AUX_I2C_REPLY_NACK:
                        DRM_DEBUG_KMS("aux_i2c nack\n");
                        return -EREMOTEIO;
                case AUX_I2C_REPLY_DEFER:
                        DRM_DEBUG_KMS("aux_i2c defer\n");
                        udelay(100);
                        break;
                default:
                        DRM_ERROR("aux_i2c invalid reply 0x%02x\n", reply[0]);
                        return -EREMOTEIO;
                }
        }

        DRM_ERROR("too many retries, giving up\n");
        return -EREMOTEIO;
}

static int
intel_dp_i2c_init(struct intel_dp *intel_dp,
                  struct intel_connector *intel_connector, const char *name)
{
        DRM_DEBUG_KMS("i2c_init %s\n", name);
        intel_dp->algo.running = false;
        intel_dp->algo.address = 0;
        intel_dp->algo.aux_ch = intel_dp_i2c_aux_ch;

        memset(&intel_dp->adapter, '\0', sizeof (intel_dp->adapter));
        intel_dp->adapter.owner = THIS_MODULE;
        intel_dp->adapter.class = I2C_CLASS_DDC;
        strncpy (intel_dp->adapter.name, name, sizeof(intel_dp->adapter.name) - 1);
        intel_dp->adapter.name[sizeof(intel_dp->adapter.name) - 1] = '\0';
        intel_dp->adapter.algo_data = &intel_dp->algo;
        intel_dp->adapter.dev.parent = &intel_connector->base.kdev;

        return i2c_dp_aux_add_bus(&intel_dp->adapter);
}

static bool
intel_dp_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
                    struct drm_display_mode *adjusted_mode)
{
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
        int lane_count, clock;
        int max_lane_count = intel_dp_max_lane_count(intel_dp);
        int max_clock = intel_dp_max_link_bw(intel_dp) == DP_LINK_BW_2_7 ? 1 : 0;
        static int bws[2] = { DP_LINK_BW_1_62, DP_LINK_BW_2_7 };

        if (is_edp(intel_dp) && dev_priv->panel_fixed_mode) {
                intel_fixed_panel_mode(dev_priv->panel_fixed_mode, adjusted_mode);
                intel_pch_panel_fitting(dev, DRM_MODE_SCALE_FULLSCREEN,
                                        mode, adjusted_mode);
                /*
                 * the mode->clock is used to calculate the Data&Link M/N
                 * of the pipe. For the eDP the fixed clock should be used.
                 */
                mode->clock = dev_priv->panel_fixed_mode->clock;
        }

        for (lane_count = 1; lane_count <= max_lane_count; lane_count <<= 1) {
                for (clock = 0; clock <= max_clock; clock++) {
                        int link_avail = intel_dp_max_data_rate(intel_dp_link_clock(bws[clock]), lane_count);

                        if (intel_dp_link_required(encoder->dev, intel_dp, mode->clock)
                                        <= link_avail) {
                                intel_dp->link_bw = bws[clock];
                                intel_dp->lane_count = lane_count;
                                adjusted_mode->clock = intel_dp_link_clock(intel_dp->link_bw);
                                DRM_DEBUG_KMS("Display port link bw %02x lane "
                                                "count %d clock %d\n",
                                       intel_dp->link_bw, intel_dp->lane_count,
                                       adjusted_mode->clock);
                                return true;
                        }
                }
        }

        if (is_edp(intel_dp)) {
                /* okay we failed just pick the highest */
                intel_dp->lane_count = max_lane_count;
                intel_dp->link_bw = bws[max_clock];
                adjusted_mode->clock = intel_dp_link_clock(intel_dp->link_bw);
                DRM_DEBUG_KMS("Force picking display port link bw %02x lane "
                              "count %d clock %d\n",
                              intel_dp->link_bw, intel_dp->lane_count,
                              adjusted_mode->clock);

                return true;
        }

        return false;
}

struct intel_dp_m_n {
        uint32_t        tu;
        uint32_t        gmch_m;
        uint32_t        gmch_n;
        uint32_t        link_m;
        uint32_t        link_n;
};

static void
intel_reduce_ratio(uint32_t *num, uint32_t *den)
{
        while (*num > 0xffffff || *den > 0xffffff) {
                *num >>= 1;
                *den >>= 1;
        }
}

static void
intel_dp_compute_m_n(int bpp,
                     int nlanes,
                     int pixel_clock,
                     int link_clock,
                     struct intel_dp_m_n *m_n)
{
        m_n->tu = 64;
        m_n->gmch_m = (pixel_clock * bpp) >> 3;
        m_n->gmch_n = link_clock * nlanes;
        intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
        m_n->link_m = pixel_clock;
        m_n->link_n = link_clock;
        intel_reduce_ratio(&m_n->link_m, &m_n->link_n);
}

void
intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
                 struct drm_display_mode *adjusted_mode)
{
        struct drm_device *dev = crtc->dev;
        struct drm_mode_config *mode_config = &dev->mode_config;
        struct drm_encoder *encoder;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
        int lane_count = 4;
        struct intel_dp_m_n m_n;
        int pipe = intel_crtc->pipe;

        /*
         * Find the lane count in the intel_encoder private
         */
        list_for_each_entry(encoder, &mode_config->encoder_list, head) {
                struct intel_dp *intel_dp;

                if (encoder->crtc != crtc)
                        continue;

                intel_dp = enc_to_intel_dp(encoder);
                if (intel_dp->base.type == INTEL_OUTPUT_DISPLAYPORT) {
                        lane_count = intel_dp->lane_count;
                        break;
                } else if (is_edp(intel_dp)) {
                        lane_count = dev_priv->edp.lanes;
                        break;
                }
        }

        /*
         * Compute the GMCH and Link ratios. The '3' here is
         * the number of bytes_per_pixel post-LUT, which we always
         * set up for 8-bits of R/G/B, or 3 bytes total.
         */
        intel_dp_compute_m_n(intel_crtc->bpp, lane_count,
                             mode->clock, adjusted_mode->clock, &m_n);

        if (HAS_PCH_SPLIT(dev)) {
                I915_WRITE(TRANSDATA_M1(pipe),
                           ((m_n.tu - 1) << PIPE_GMCH_DATA_M_TU_SIZE_SHIFT) |
                           m_n.gmch_m);
                I915_WRITE(TRANSDATA_N1(pipe), m_n.gmch_n);
                I915_WRITE(TRANSDPLINK_M1(pipe), m_n.link_m);
                I915_WRITE(TRANSDPLINK_N1(pipe), m_n.link_n);
        } else {
                I915_WRITE(PIPE_GMCH_DATA_M(pipe),
                           ((m_n.tu - 1) << PIPE_GMCH_DATA_M_TU_SIZE_SHIFT) |
                           m_n.gmch_m);
                I915_WRITE(PIPE_GMCH_DATA_N(pipe), m_n.gmch_n);
                I915_WRITE(PIPE_DP_LINK_M(pipe), m_n.link_m);
                I915_WRITE(PIPE_DP_LINK_N(pipe), m_n.link_n);
        }
}

static void
intel_dp_mode_set(struct drm_encoder *encoder, struct drm_display_mode *mode,
                  struct drm_display_mode *adjusted_mode)
{
        struct drm_device *dev = encoder->dev;
        struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
        struct drm_crtc *crtc = intel_dp->base.base.crtc;
        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);

        intel_dp->DP = DP_VOLTAGE_0_4 | DP_PRE_EMPHASIS_0;
        intel_dp->DP |= intel_dp->color_range;

        if (adjusted_mode->flags & DRM_MODE_FLAG_PHSYNC)
                intel_dp->DP |= DP_SYNC_HS_HIGH;
        if (adjusted_mode->flags & DRM_MODE_FLAG_PVSYNC)
                intel_dp->DP |= DP_SYNC_VS_HIGH;

        if (HAS_PCH_CPT(dev) && !is_edp(intel_dp))
                intel_dp->DP |= DP_LINK_TRAIN_OFF_CPT;
        else
                intel_dp->DP |= DP_LINK_TRAIN_OFF;

        switch (intel_dp->lane_count) {
        case 1:
                intel_dp->DP |= DP_PORT_WIDTH_1;
                break;
        case 2:
                intel_dp->DP |= DP_PORT_WIDTH_2;
                break;
        case 4:
                intel_dp->DP |= DP_PORT_WIDTH_4;
                break;
        }
        if (intel_dp->has_audio)
                intel_dp->DP |= DP_AUDIO_OUTPUT_ENABLE;

        memset(intel_dp->link_configuration, 0, DP_LINK_CONFIGURATION_SIZE);
        intel_dp->link_configuration[0] = intel_dp->link_bw;
        intel_dp->link_configuration[1] = intel_dp->lane_count;
        intel_dp->link_configuration[8] = DP_SET_ANSI_8B10B;

        /*
         * Check for DPCD version > 1.1 and enhanced framing support
         */
        if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
            (intel_dp->dpcd[DP_MAX_LANE_COUNT] & DP_ENHANCED_FRAME_CAP)) {
                intel_dp->link_configuration[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
                intel_dp->DP |= DP_ENHANCED_FRAMING;
        }

        /* CPT DP's pipe select is decided in TRANS_DP_CTL */
        if (intel_crtc->pipe == 1 && !HAS_PCH_CPT(dev))
                intel_dp->DP |= DP_PIPEB_SELECT;

        if (is_edp(intel_dp) && !is_pch_edp(intel_dp)) {
                /* don't miss out required setting for eDP */
                intel_dp->DP |= DP_PLL_ENABLE;
                if (adjusted_mode->clock < 200000)
                        intel_dp->DP |= DP_PLL_FREQ_160MHZ;
                else
                        intel_dp->DP |= DP_PLL_FREQ_270MHZ;
        }
}

static void ironlake_edp_panel_vdd_on(struct intel_dp *intel_dp)
{
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pp;

        /*
         * If the panel wasn't on, make sure there's not a currently
         * active PP sequence before enabling AUX VDD.
         */
        if (!(I915_READ(PCH_PP_STATUS) & PP_ON))
                msleep(dev_priv->panel_t3);

        pp = I915_READ(PCH_PP_CONTROL);
        pp |= EDP_FORCE_VDD;
        I915_WRITE(PCH_PP_CONTROL, pp);
        POSTING_READ(PCH_PP_CONTROL);
}

static void ironlake_edp_panel_vdd_off(struct intel_dp *intel_dp)
{
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pp;

        pp = I915_READ(PCH_PP_CONTROL);
        pp &= ~EDP_FORCE_VDD;
        I915_WRITE(PCH_PP_CONTROL, pp);
        POSTING_READ(PCH_PP_CONTROL);

        /* Make sure sequencer is idle before allowing subsequent activity */
        msleep(dev_priv->panel_t12);
}

/* Returns true if the panel was already on when called */
static bool ironlake_edp_panel_on (struct intel_dp *intel_dp)
{
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pp, idle_on_mask = PP_ON | PP_SEQUENCE_STATE_ON_IDLE;

        if (I915_READ(PCH_PP_STATUS) & PP_ON)
                return true;

        pp = I915_READ(PCH_PP_CONTROL);

        /* ILK workaround: disable reset around power sequence */
        pp &= ~PANEL_POWER_RESET;
        I915_WRITE(PCH_PP_CONTROL, pp);
        POSTING_READ(PCH_PP_CONTROL);

        pp |= PANEL_UNLOCK_REGS | POWER_TARGET_ON;
        I915_WRITE(PCH_PP_CONTROL, pp);
        POSTING_READ(PCH_PP_CONTROL);

        if (wait_for((I915_READ(PCH_PP_STATUS) & idle_on_mask) == idle_on_mask,
                     5000))
                DRM_ERROR("panel on wait timed out: 0x%08x\n",
                          I915_READ(PCH_PP_STATUS));

        pp |= PANEL_POWER_RESET; /* restore panel reset bit */
        I915_WRITE(PCH_PP_CONTROL, pp);
        POSTING_READ(PCH_PP_CONTROL);

        return false;
}

static void ironlake_edp_panel_off (struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pp, idle_off_mask = PP_ON | PP_SEQUENCE_MASK |
                PP_CYCLE_DELAY_ACTIVE | PP_SEQUENCE_STATE_MASK;

        pp = I915_READ(PCH_PP_CONTROL);

        /* ILK workaround: disable reset around power sequence */
        pp &= ~PANEL_POWER_RESET;
        I915_WRITE(PCH_PP_CONTROL, pp);
        POSTING_READ(PCH_PP_CONTROL);

        pp &= ~POWER_TARGET_ON;
        I915_WRITE(PCH_PP_CONTROL, pp);
        POSTING_READ(PCH_PP_CONTROL);

        if (wait_for((I915_READ(PCH_PP_STATUS) & idle_off_mask) == 0, 5000))
                DRM_ERROR("panel off wait timed out: 0x%08x\n",
                          I915_READ(PCH_PP_STATUS));

        pp |= PANEL_POWER_RESET; /* restore panel reset bit */
        I915_WRITE(PCH_PP_CONTROL, pp);
        POSTING_READ(PCH_PP_CONTROL);
}

static void ironlake_edp_backlight_on (struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pp;

        DRM_DEBUG_KMS("\n");
        /*
         * If we enable the backlight right away following a panel power
         * on, we may see slight flicker as the panel syncs with the eDP
         * link.  So delay a bit to make sure the image is solid before
         * allowing it to appear.
         */
        msleep(300);
        pp = I915_READ(PCH_PP_CONTROL);
        pp |= EDP_BLC_ENABLE;
        I915_WRITE(PCH_PP_CONTROL, pp);
}

static void ironlake_edp_backlight_off (struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 pp;

        DRM_DEBUG_KMS("\n");
        pp = I915_READ(PCH_PP_CONTROL);
        pp &= ~EDP_BLC_ENABLE;
        I915_WRITE(PCH_PP_CONTROL, pp);
}

static void ironlake_edp_pll_on(struct drm_encoder *encoder)
{
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 dpa_ctl;

        DRM_DEBUG_KMS("\n");
        dpa_ctl = I915_READ(DP_A);
        dpa_ctl |= DP_PLL_ENABLE;
        I915_WRITE(DP_A, dpa_ctl);
        POSTING_READ(DP_A);
        udelay(200);
}

static void ironlake_edp_pll_off(struct drm_encoder *encoder)
{
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 dpa_ctl;

        dpa_ctl = I915_READ(DP_A);
        dpa_ctl &= ~DP_PLL_ENABLE;
        I915_WRITE(DP_A, dpa_ctl);
        POSTING_READ(DP_A);
        udelay(200);
}

/* If the sink supports it, try to set the power state appropriately */
static void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
{
        int ret, i;

        /* Should have a valid DPCD by this point */
        if (intel_dp->dpcd[DP_DPCD_REV] < 0x11)
                return;

        if (mode != DRM_MODE_DPMS_ON) {
                ret = intel_dp_aux_native_write_1(intel_dp, DP_SET_POWER,
                                                  DP_SET_POWER_D3);
                if (ret != 1)
                        DRM_DEBUG_DRIVER("failed to write sink power state\n");
        } else {
                /*
                 * When turning on, we need to retry for 1ms to give the sink
                 * time to wake up.
                 */
                for (i = 0; i < 3; i++) {
                        ret = intel_dp_aux_native_write_1(intel_dp,
                                                          DP_SET_POWER,
                                                          DP_SET_POWER_D0);
                        if (ret == 1)
                                break;
                        msleep(1);
                }
        }
}

static void intel_dp_prepare(struct drm_encoder *encoder)
{
        struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
        struct drm_device *dev = encoder->dev;

        /* Wake up the sink first */
        intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);

        if (is_edp(intel_dp)) {
                ironlake_edp_backlight_off(dev);
                ironlake_edp_panel_off(dev);
                if (!is_pch_edp(intel_dp))
                        ironlake_edp_pll_on(encoder);
                else
                        ironlake_edp_pll_off(encoder);

        }
        intel_dp_link_down(intel_dp);
}

static void intel_dp_commit(struct drm_encoder *encoder)
{
        struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
        struct drm_device *dev = encoder->dev;

        if (is_edp(intel_dp))
                ironlake_edp_panel_vdd_on(intel_dp);

        intel_dp_start_link_train(intel_dp);

        if (is_edp(intel_dp)) {
                ironlake_edp_panel_on(intel_dp);
                ironlake_edp_panel_vdd_off(intel_dp);
        }

        intel_dp_complete_link_train(intel_dp);

        if (is_edp(intel_dp))
                ironlake_edp_backlight_on(dev);

        intel_dp->dpms_mode = DRM_MODE_DPMS_ON;
}

static void
intel_dp_dpms(struct drm_encoder *encoder, int mode)
{
        struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t dp_reg = I915_READ(intel_dp->output_reg);

        if (mode != DRM_MODE_DPMS_ON) {
                if (is_edp(intel_dp))
                        ironlake_edp_backlight_off(dev);
                intel_dp_sink_dpms(intel_dp, mode);
                intel_dp_link_down(intel_dp);
                if (is_edp(intel_dp))
                        ironlake_edp_panel_off(dev);
                if (is_edp(intel_dp) && !is_pch_edp(intel_dp))
                        ironlake_edp_pll_off(encoder);
        } else {
                if (is_edp(intel_dp))
                        ironlake_edp_panel_vdd_on(intel_dp);
                intel_dp_sink_dpms(intel_dp, mode);
                if (!(dp_reg & DP_PORT_EN)) {
                        intel_dp_start_link_train(intel_dp);
                        if (is_edp(intel_dp)) {
                                ironlake_edp_panel_on(intel_dp);
                                ironlake_edp_panel_vdd_off(intel_dp);
                        }
                        intel_dp_complete_link_train(intel_dp);
                }
                if (is_edp(intel_dp))
                        ironlake_edp_backlight_on(dev);
        }
        intel_dp->dpms_mode = mode;
}

/*
 * Native read with retry for link status and receiver capability reads for
 * cases where the sink may still be asleep.
 */
static bool
intel_dp_aux_native_read_retry(struct intel_dp *intel_dp, uint16_t address,
                               uint8_t *recv, int recv_bytes)
{
        int ret, i;

        /*
         * Sinks are *supposed* to come up within 1ms from an off state,
         * but we're also supposed to retry 3 times per the spec.
         */
        for (i = 0; i < 3; i++) {
                ret = intel_dp_aux_native_read(intel_dp, address, recv,
                                               recv_bytes);
                if (ret == recv_bytes)
                        return true;
                msleep(1);
        }

        return false;
}

/*
 * Fetch AUX CH registers 0x202 - 0x207 which contain
 * link status information
 */
static bool
intel_dp_get_link_status(struct intel_dp *intel_dp)
{
        return intel_dp_aux_native_read_retry(intel_dp,
                                              DP_LANE0_1_STATUS,
                                              intel_dp->link_status,
                                              DP_LINK_STATUS_SIZE);
}

static uint8_t
intel_dp_link_status(uint8_t link_status[DP_LINK_STATUS_SIZE],
                     int r)
{
        return link_status[r - DP_LANE0_1_STATUS];
}

static uint8_t
intel_get_adjust_request_voltage(uint8_t link_status[DP_LINK_STATUS_SIZE],
                                 int lane)
{
        int         i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
        int         s = ((lane & 1) ?
                         DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT :
                         DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT);
        uint8_t l = intel_dp_link_status(link_status, i);

        return ((l >> s) & 3) << DP_TRAIN_VOLTAGE_SWING_SHIFT;
}

static uint8_t
intel_get_adjust_request_pre_emphasis(uint8_t link_status[DP_LINK_STATUS_SIZE],
                                      int lane)
{
        int         i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
        int         s = ((lane & 1) ?
                         DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT :
                         DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT);
        uint8_t l = intel_dp_link_status(link_status, i);

        return ((l >> s) & 3) << DP_TRAIN_PRE_EMPHASIS_SHIFT;
}


#if 0
static char     *voltage_names[] = {
        "0.4V", "0.6V", "0.8V", "1.2V"
};
static char     *pre_emph_names[] = {
        "0dB", "3.5dB", "6dB", "9.5dB"
};
static char     *link_train_names[] = {
        "pattern 1", "pattern 2", "idle", "off"
};
#endif

/*
 * These are source-specific values; current Intel hardware supports
 * a maximum voltage of 800mV and a maximum pre-emphasis of 6dB
 */
#define I830_DP_VOLTAGE_MAX         DP_TRAIN_VOLTAGE_SWING_800

static uint8_t
intel_dp_pre_emphasis_max(uint8_t voltage_swing)
{
        switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
        case DP_TRAIN_VOLTAGE_SWING_400:
                return DP_TRAIN_PRE_EMPHASIS_6;
        case DP_TRAIN_VOLTAGE_SWING_600:
                return DP_TRAIN_PRE_EMPHASIS_6;
        case DP_TRAIN_VOLTAGE_SWING_800:
                return DP_TRAIN_PRE_EMPHASIS_3_5;
        case DP_TRAIN_VOLTAGE_SWING_1200:
        default:
                return DP_TRAIN_PRE_EMPHASIS_0;
        }
}

static void
intel_get_adjust_train(struct intel_dp *intel_dp)
{
        uint8_t v = 0;
        uint8_t p = 0;
        int lane;

        for (lane = 0; lane < intel_dp->lane_count; lane++) {
                uint8_t this_v = intel_get_adjust_request_voltage(intel_dp->link_status, lane);
                uint8_t this_p = intel_get_adjust_request_pre_emphasis(intel_dp->link_status, lane);

                if (this_v > v)
                        v = this_v;
                if (this_p > p)
                        p = this_p;
        }

        if (v >= I830_DP_VOLTAGE_MAX)
                v = I830_DP_VOLTAGE_MAX | DP_TRAIN_MAX_SWING_REACHED;

        if (p >= intel_dp_pre_emphasis_max(v))
                p = intel_dp_pre_emphasis_max(v) | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;

        for (lane = 0; lane < 4; lane++)
                intel_dp->train_set[lane] = v | p;
}

static uint32_t
intel_dp_signal_levels(uint8_t train_set, int lane_count)
{
        uint32_t        signal_levels = 0;

        switch (train_set & DP_TRAIN_VOLTAGE_SWING_MASK) {
        case DP_TRAIN_VOLTAGE_SWING_400:
        default:
                signal_levels |= DP_VOLTAGE_0_4;
                break;
        case DP_TRAIN_VOLTAGE_SWING_600:
                signal_levels |= DP_VOLTAGE_0_6;
                break;
        case DP_TRAIN_VOLTAGE_SWING_800:
                signal_levels |= DP_VOLTAGE_0_8;
                break;
        case DP_TRAIN_VOLTAGE_SWING_1200:
                signal_levels |= DP_VOLTAGE_1_2;
                break;
        }
        switch (train_set & DP_TRAIN_PRE_EMPHASIS_MASK) {
        case DP_TRAIN_PRE_EMPHASIS_0:
        default:
                signal_levels |= DP_PRE_EMPHASIS_0;
                break;
        case DP_TRAIN_PRE_EMPHASIS_3_5:
                signal_levels |= DP_PRE_EMPHASIS_3_5;
                break;
        case DP_TRAIN_PRE_EMPHASIS_6:
                signal_levels |= DP_PRE_EMPHASIS_6;
                break;
        case DP_TRAIN_PRE_EMPHASIS_9_5:
                signal_levels |= DP_PRE_EMPHASIS_9_5;
                break;
        }
        return signal_levels;
}

/* Gen6's DP voltage swing and pre-emphasis control */
static uint32_t
intel_gen6_edp_signal_levels(uint8_t train_set)
{
        int signal_levels = train_set & (DP_TRAIN_VOLTAGE_SWING_MASK |
                                         DP_TRAIN_PRE_EMPHASIS_MASK);
        switch (signal_levels) {
        case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_0:
        case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_0:
                return EDP_LINK_TRAIN_400_600MV_0DB_SNB_B;
        case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_3_5:
                return EDP_LINK_TRAIN_400MV_3_5DB_SNB_B;
        case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_6:
        case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_6:
                return EDP_LINK_TRAIN_400_600MV_6DB_SNB_B;
        case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_3_5:
        case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_3_5:
                return EDP_LINK_TRAIN_600_800MV_3_5DB_SNB_B;
        case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_0:
        case DP_TRAIN_VOLTAGE_SWING_1200 | DP_TRAIN_PRE_EMPHASIS_0:
                return EDP_LINK_TRAIN_800_1200MV_0DB_SNB_B;
        default:
                DRM_DEBUG_KMS("Unsupported voltage swing/pre-emphasis level:"
                              "0x%x\n", signal_levels);
                return EDP_LINK_TRAIN_400_600MV_0DB_SNB_B;
        }
}

static uint8_t
intel_get_lane_status(uint8_t link_status[DP_LINK_STATUS_SIZE],
                      int lane)
{
        int i = DP_LANE0_1_STATUS + (lane >> 1);
        int s = (lane & 1) * 4;
        uint8_t l = intel_dp_link_status(link_status, i);

        return (l >> s) & 0xf;
}

/* Check for clock recovery is done on all channels */
static bool
intel_clock_recovery_ok(uint8_t link_status[DP_LINK_STATUS_SIZE], int lane_count)
{
        int lane;
        uint8_t lane_status;

        for (lane = 0; lane < lane_count; lane++) {
                lane_status = intel_get_lane_status(link_status, lane);
                if ((lane_status & DP_LANE_CR_DONE) == 0)
                        return false;
        }
        return true;
}

/* Check to see if channel eq is done on all channels */
#define CHANNEL_EQ_BITS (DP_LANE_CR_DONE|\
                         DP_LANE_CHANNEL_EQ_DONE|\
                         DP_LANE_SYMBOL_LOCKED)
static bool
intel_channel_eq_ok(struct intel_dp *intel_dp)
{
        uint8_t lane_align;
        uint8_t lane_status;
        int lane;

        lane_align = intel_dp_link_status(intel_dp->link_status,
                                          DP_LANE_ALIGN_STATUS_UPDATED);
        if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0)
                return false;
        for (lane = 0; lane < intel_dp->lane_count; lane++) {
                lane_status = intel_get_lane_status(intel_dp->link_status, lane);
                if ((lane_status & CHANNEL_EQ_BITS) != CHANNEL_EQ_BITS)
                        return false;
        }
        return true;
}

static bool
intel_dp_set_link_train(struct intel_dp *intel_dp,
                        uint32_t dp_reg_value,
                        uint8_t dp_train_pat)
{
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        int ret;

        I915_WRITE(intel_dp->output_reg, dp_reg_value);
        POSTING_READ(intel_dp->output_reg);

        intel_dp_aux_native_write_1(intel_dp,
                                    DP_TRAINING_PATTERN_SET,
                                    dp_train_pat);

        ret = intel_dp_aux_native_write(intel_dp,
                                        DP_TRAINING_LANE0_SET,
                                        intel_dp->train_set, 4);
        if (ret != 4)
                return false;

        return true;
}

/* Enable corresponding port and start training pattern 1 */
static void
intel_dp_start_link_train(struct intel_dp *intel_dp)
{
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *intel_crtc = to_intel_crtc(intel_dp->base.base.crtc);
        int i;
        uint8_t voltage;
        bool clock_recovery = false;
        int tries;
        u32 reg;
        uint32_t DP = intel_dp->DP;

        /*
         * On CPT we have to enable the port in training pattern 1, which
         * will happen below in intel_dp_set_link_train.  Otherwise, enable
         * the port and wait for it to become active.
         */
        if (!HAS_PCH_CPT(dev)) {
                I915_WRITE(intel_dp->output_reg, intel_dp->DP);
                POSTING_READ(intel_dp->output_reg);
                intel_wait_for_vblank(dev, intel_crtc->pipe);
        }

        /* Write the link configuration data */
        intel_dp_aux_native_write(intel_dp, DP_LINK_BW_SET,
                                  intel_dp->link_configuration,
                                  DP_LINK_CONFIGURATION_SIZE);

        DP |= DP_PORT_EN;
        if (HAS_PCH_CPT(dev) && !is_edp(intel_dp))
                DP &= ~DP_LINK_TRAIN_MASK_CPT;
        else
                DP &= ~DP_LINK_TRAIN_MASK;
        memset(intel_dp->train_set, 0, 4);
        voltage = 0xff;
        tries = 0;
        clock_recovery = false;
        for (;;) {
                /* Use intel_dp->train_set[0] to set the voltage and pre emphasis values */
                uint32_t    signal_levels;
                if (IS_GEN6(dev) && is_edp(intel_dp)) {
                        signal_levels = intel_gen6_edp_signal_levels(intel_dp->train_set[0]);
                        DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_SNB) | signal_levels;
                } else {
                        signal_levels = intel_dp_signal_levels(intel_dp->train_set[0], intel_dp->lane_count);
                        DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
                }

                if (HAS_PCH_CPT(dev) && !is_edp(intel_dp))
                        reg = DP | DP_LINK_TRAIN_PAT_1_CPT;
                else
                        reg = DP | DP_LINK_TRAIN_PAT_1;

                if (!intel_dp_set_link_train(intel_dp, reg,
                                             DP_TRAINING_PATTERN_1 |
                                             DP_LINK_SCRAMBLING_DISABLE))
                        break;
                /* Set training pattern 1 */

                udelay(100);
                if (!intel_dp_get_link_status(intel_dp))
                        break;

                if (intel_clock_recovery_ok(intel_dp->link_status, intel_dp->lane_count)) {
                        clock_recovery = true;
                        break;
                }

                /* Check to see if we've tried the max voltage */
                for (i = 0; i < intel_dp->lane_count; i++)
                        if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0)
                                break;
                if (i == intel_dp->lane_count)
                        break;

                /* Check to see if we've tried the same voltage 5 times */
                if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
                        ++tries;
                        if (tries == 5)
                                break;
                } else
                        tries = 0;
                voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;

                /* Compute new intel_dp->train_set as requested by target */
                intel_get_adjust_train(intel_dp);
        }

        intel_dp->DP = DP;
}

static void
intel_dp_complete_link_train(struct intel_dp *intel_dp)
{
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        bool channel_eq = false;
        int tries, cr_tries;
        u32 reg;
        uint32_t DP = intel_dp->DP;

        /* channel equalization */
        tries = 0;
        cr_tries = 0;
        channel_eq = false;
        for (;;) {
                /* Use intel_dp->train_set[0] to set the voltage and pre emphasis values */
                uint32_t    signal_levels;

                if (cr_tries > 5) {
                        DRM_ERROR("failed to train DP, aborting\n");
                        intel_dp_link_down(intel_dp);
                        break;
                }

                if (IS_GEN6(dev) && is_edp(intel_dp)) {
                        signal_levels = intel_gen6_edp_signal_levels(intel_dp->train_set[0]);
                        DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_SNB) | signal_levels;
                } else {
                        signal_levels = intel_dp_signal_levels(intel_dp->train_set[0], intel_dp->lane_count);
                        DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
                }

                if (HAS_PCH_CPT(dev) && !is_edp(intel_dp))
                        reg = DP | DP_LINK_TRAIN_PAT_2_CPT;
                else
                        reg = DP | DP_LINK_TRAIN_PAT_2;

                /* channel eq pattern */
                if (!intel_dp_set_link_train(intel_dp, reg,
                                             DP_TRAINING_PATTERN_2 |
                                             DP_LINK_SCRAMBLING_DISABLE))
                        break;

                udelay(400);
                if (!intel_dp_get_link_status(intel_dp))
                        break;

                /* Make sure clock is still ok */
                if (!intel_clock_recovery_ok(intel_dp->link_status, intel_dp->lane_count)) {
                        intel_dp_start_link_train(intel_dp);
                        cr_tries++;
                        continue;
                }

                if (intel_channel_eq_ok(intel_dp)) {
                        channel_eq = true;
                        break;
                }

                /* Try 5 times, then try clock recovery if that fails */
                if (tries > 5) {
                        intel_dp_link_down(intel_dp);
                        intel_dp_start_link_train(intel_dp);
                        tries = 0;
                        cr_tries++;
                        continue;
                }

                /* Compute new intel_dp->train_set as requested by target */
                intel_get_adjust_train(intel_dp);
                ++tries;
        }

        if (HAS_PCH_CPT(dev) && !is_edp(intel_dp))
                reg = DP | DP_LINK_TRAIN_OFF_CPT;
        else
                reg = DP | DP_LINK_TRAIN_OFF;

        I915_WRITE(intel_dp->output_reg, reg);
        POSTING_READ(intel_dp->output_reg);
        intel_dp_aux_native_write_1(intel_dp,
                                    DP_TRAINING_PATTERN_SET, DP_TRAINING_PATTERN_DISABLE);
}

static void
intel_dp_link_down(struct intel_dp *intel_dp)
{
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t DP = intel_dp->DP;

        if ((I915_READ(intel_dp->output_reg) & DP_PORT_EN) == 0)
                return;

        DRM_DEBUG_KMS("\n");

        if (is_edp(intel_dp)) {
                DP &= ~DP_PLL_ENABLE;
                I915_WRITE(intel_dp->output_reg, DP);
                POSTING_READ(intel_dp->output_reg);
                udelay(100);
        }

        if (HAS_PCH_CPT(dev) && !is_edp(intel_dp)) {
                DP &= ~DP_LINK_TRAIN_MASK_CPT;
                I915_WRITE(intel_dp->output_reg, DP | DP_LINK_TRAIN_PAT_IDLE_CPT);
        } else {
                DP &= ~DP_LINK_TRAIN_MASK;
                I915_WRITE(intel_dp->output_reg, DP | DP_LINK_TRAIN_PAT_IDLE);
        }
        POSTING_READ(intel_dp->output_reg);

        msleep(17);

        if (is_edp(intel_dp))
                DP |= DP_LINK_TRAIN_OFF;

        if (!HAS_PCH_CPT(dev) &&
            I915_READ(intel_dp->output_reg) & DP_PIPEB_SELECT) {
                struct drm_crtc *crtc = intel_dp->base.base.crtc;

                /* Hardware workaround: leaving our transcoder select
                 * set to transcoder B while it's off will prevent the
                 * corresponding HDMI output on transcoder A.
                 *
                 * Combine this with another hardware workaround:
                 * transcoder select bit can only be cleared while the
                 * port is enabled.
                 */
                DP &= ~DP_PIPEB_SELECT;
                I915_WRITE(intel_dp->output_reg, DP);

                /* Changes to enable or select take place the vblank
                 * after being written.
                 */
                if (crtc == NULL) {
                        /* We can arrive here never having been attached
                         * to a CRTC, for instance, due to inheriting
                         * random state from the BIOS.
                         *
                         * If the pipe is not running, play safe and
                         * wait for the clocks to stabilise before
                         * continuing.
                         */
                        POSTING_READ(intel_dp->output_reg);
                        msleep(50);
                } else
                        intel_wait_for_vblank(dev, to_intel_crtc(crtc)->pipe);
        }

        I915_WRITE(intel_dp->output_reg, DP & ~DP_PORT_EN);
        POSTING_READ(intel_dp->output_reg);
}

static bool
intel_dp_get_dpcd(struct intel_dp *intel_dp)
{
        if (intel_dp_aux_native_read_retry(intel_dp, 0x000, intel_dp->dpcd,
                                           sizeof (intel_dp->dpcd)) &&
            (intel_dp->dpcd[DP_DPCD_REV] != 0)) {
                return true;
        }

        return false;
}

/*
 * According to DP spec
 * 5.1.2:
 *  1. Read DPCD
 *  2. Configure link according to Receiver Capabilities
 *  3. Use Link Training from 2.5.3.3 and 3.5.1.3
 *  4. Check link status on receipt of hot-plug interrupt
 */

static void
intel_dp_check_link_status(struct intel_dp *intel_dp)
{
        if (intel_dp->dpms_mode != DRM_MODE_DPMS_ON)
                return;

        if (!intel_dp->base.base.crtc)
                return;

        /* Try to read receiver status if the link appears to be up */
        if (!intel_dp_get_link_status(intel_dp)) {
                intel_dp_link_down(intel_dp);
                return;
        }

        /* Now read the DPCD to see if it's actually running */
        if (!intel_dp_get_dpcd(intel_dp)) {
                intel_dp_link_down(intel_dp);
                return;
        }

        if (!intel_channel_eq_ok(intel_dp)) {
                DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n",
                              drm_get_encoder_name(&intel_dp->base.base));
                intel_dp_start_link_train(intel_dp);
                intel_dp_complete_link_train(intel_dp);
        }
}

static enum drm_connector_status
intel_dp_detect_dpcd(struct intel_dp *intel_dp)
{
        if (intel_dp_get_dpcd(intel_dp))
                return connector_status_connected;
        return connector_status_disconnected;
}

static enum drm_connector_status
ironlake_dp_detect(struct intel_dp *intel_dp)
{
        enum drm_connector_status status;

        /* Can't disconnect eDP, but you can close the lid... */
        if (is_edp(intel_dp)) {
                status = intel_panel_detect(intel_dp->base.base.dev);
                if (status == connector_status_unknown)
                        status = connector_status_connected;
                return status;
        }

        return intel_dp_detect_dpcd(intel_dp);
}

static enum drm_connector_status
g4x_dp_detect(struct intel_dp *intel_dp)
{
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t temp, bit;

        switch (intel_dp->output_reg) {
        case DP_B:
                bit = DPB_HOTPLUG_INT_STATUS;
                break;
        case DP_C:
                bit = DPC_HOTPLUG_INT_STATUS;
                break;
        case DP_D:
                bit = DPD_HOTPLUG_INT_STATUS;
                break;
        default:
                return connector_status_unknown;
        }

        temp = I915_READ(PORT_HOTPLUG_STAT);

        if ((temp & bit) == 0)
                return connector_status_disconnected;

        return intel_dp_detect_dpcd(intel_dp);
}

/**
 * Uses CRT_HOTPLUG_EN and CRT_HOTPLUG_STAT to detect DP connection.
 *
 * \return true if DP port is connected.
 * \return false if DP port is disconnected.
 */
static enum drm_connector_status
intel_dp_detect(struct drm_connector *connector, bool force)
{
        struct intel_dp *intel_dp = intel_attached_dp(connector);
        struct drm_device *dev = intel_dp->base.base.dev;
        enum drm_connector_status status;
        struct edid *edid = NULL;

        intel_dp->has_audio = false;

        if (HAS_PCH_SPLIT(dev))
                status = ironlake_dp_detect(intel_dp);
        else
                status = g4x_dp_detect(intel_dp);

        DRM_DEBUG_KMS("DPCD: %02hx%02hx%02hx%02hx%02hx%02hx%02hx%02hx\n",
                      intel_dp->dpcd[0], intel_dp->dpcd[1], intel_dp->dpcd[2],
                      intel_dp->dpcd[3], intel_dp->dpcd[4], intel_dp->dpcd[5],
                      intel_dp->dpcd[6], intel_dp->dpcd[7]);

        if (status != connector_status_connected)
                return status;

        if (intel_dp->force_audio) {
                intel_dp->has_audio = intel_dp->force_audio > 0;
        } else {
                edid = drm_get_edid(connector, &intel_dp->adapter);
                if (edid) {
                        intel_dp->has_audio = drm_detect_monitor_audio(edid);
                        connector->display_info.raw_edid = NULL;
                        kfree(edid);
                }
        }

        return connector_status_connected;
}

static int intel_dp_get_modes(struct drm_connector *connector)
{
        struct intel_dp *intel_dp = intel_attached_dp(connector);
        struct drm_device *dev = intel_dp->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        int ret;

        /* We should parse the EDID data and find out if it has an audio sink
         */

        ret = intel_ddc_get_modes(connector, &intel_dp->adapter);
        if (ret) {
                if (is_edp(intel_dp) && !dev_priv->panel_fixed_mode) {
                        struct drm_display_mode *newmode;
                        list_for_each_entry(newmode, &connector->probed_modes,
                                            head) {
                                if (newmode->type & DRM_MODE_TYPE_PREFERRED) {
                                        dev_priv->panel_fixed_mode =
                                                drm_mode_duplicate(dev, newmode);
                                        break;
                                }
                        }
                }

                return ret;
        }

        /* if eDP has no EDID, try to use fixed panel mode from VBT */
        if (is_edp(intel_dp)) {
                if (dev_priv->panel_fixed_mode != NULL) {
                        struct drm_display_mode *mode;
                        mode = drm_mode_duplicate(dev, dev_priv->panel_fixed_mode);
                        drm_mode_probed_add(connector, mode);
                        return 1;
                }
        }
        return 0;
}

static bool
intel_dp_detect_audio(struct drm_connector *connector)
{
        struct intel_dp *intel_dp = intel_attached_dp(connector);
        struct edid *edid;
        bool has_audio = false;

        edid = drm_get_edid(connector, &intel_dp->adapter);
        if (edid) {
                has_audio = drm_detect_monitor_audio(edid);

                connector->display_info.raw_edid = NULL;
                kfree(edid);
        }

        return has_audio;
}

static int
intel_dp_set_property(struct drm_connector *connector,
                      struct drm_property *property,
                      uint64_t val)
{
        struct drm_i915_private *dev_priv = connector->dev->dev_private;
        struct intel_dp *intel_dp = intel_attached_dp(connector);
        int ret;

        ret = drm_connector_property_set_value(connector, property, val);
        if (ret)
                return ret;

        if (property == dev_priv->force_audio_property) {
                int i = val;
                bool has_audio;

                if (i == intel_dp->force_audio)
                        return 0;

                intel_dp->force_audio = i;

                if (i == 0)
                        has_audio = intel_dp_detect_audio(connector);
                else
                        has_audio = i > 0;

                if (has_audio == intel_dp->has_audio)
                        return 0;

                intel_dp->has_audio = has_audio;
                goto done;
        }

        if (property == dev_priv->broadcast_rgb_property) {
                if (val == !!intel_dp->color_range)
                        return 0;

                intel_dp->color_range = val ? DP_COLOR_RANGE_16_235 : 0;
                goto done;
        }

        return -EINVAL;

done:
        if (intel_dp->base.base.crtc) {
                struct drm_crtc *crtc = intel_dp->base.base.crtc;
                drm_crtc_helper_set_mode(crtc, &crtc->mode,
                                         crtc->x, crtc->y,
                                         crtc->fb);
        }

        return 0;
}

static void
intel_dp_destroy (struct drm_connector *connector)
{
        struct drm_device *dev = connector->dev;

        if (intel_dpd_is_edp(dev))
                intel_panel_destroy_backlight(dev);

        drm_sysfs_connector_remove(connector);
        drm_connector_cleanup(connector);
        kfree(connector);
}

static void intel_dp_encoder_destroy(struct drm_encoder *encoder)
{
        struct intel_dp *intel_dp = enc_to_intel_dp(encoder);

        i2c_del_adapter(&intel_dp->adapter);
        drm_encoder_cleanup(encoder);
        kfree(intel_dp);
}

static const struct drm_encoder_helper_funcs intel_dp_helper_funcs = {
        .dpms = intel_dp_dpms,
        .mode_fixup = intel_dp_mode_fixup,
        .prepare = intel_dp_prepare,
        .mode_set = intel_dp_mode_set,
        .commit = intel_dp_commit,
};

static const struct drm_connector_funcs intel_dp_connector_funcs = {
        .dpms = drm_helper_connector_dpms,
        .detect = intel_dp_detect,
        .fill_modes = drm_helper_probe_single_connector_modes,
        .set_property = intel_dp_set_property,
        .destroy = intel_dp_destroy,
};

static const struct drm_connector_helper_funcs intel_dp_connector_helper_funcs = {
        .get_modes = intel_dp_get_modes,
        .mode_valid = intel_dp_mode_valid,
        .best_encoder = intel_best_encoder,
};

static const struct drm_encoder_funcs intel_dp_enc_funcs = {
        .destroy = intel_dp_encoder_destroy,
};

static void
intel_dp_hot_plug(struct intel_encoder *intel_encoder)
{
        struct intel_dp *intel_dp = container_of(intel_encoder, struct intel_dp, base);

        intel_dp_check_link_status(intel_dp);
}

/* Return which DP Port should be selected for Transcoder DP control */
int
intel_trans_dp_port_sel (struct drm_crtc *crtc)
{
        struct drm_device *dev = crtc->dev;
        struct drm_mode_config *mode_config = &dev->mode_config;
        struct drm_encoder *encoder;

        list_for_each_entry(encoder, &mode_config->encoder_list, head) {
                struct intel_dp *intel_dp;

                if (encoder->crtc != crtc)
                        continue;

                intel_dp = enc_to_intel_dp(encoder);
                if (intel_dp->base.type == INTEL_OUTPUT_DISPLAYPORT)
                        return intel_dp->output_reg;
        }

        return -1;
}

/* check the VBT to see whether the eDP is on DP-D port */
bool intel_dpd_is_edp(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct child_device_config *p_child;
        int i;

        if (!dev_priv->child_dev_num)
                return false;

        for (i = 0; i < dev_priv->child_dev_num; i++) {
                p_child = dev_priv->child_dev + i;

                if (p_child->dvo_port == PORT_IDPD &&
                    p_child->device_type == DEVICE_TYPE_eDP)
                        return true;
        }
        return false;
}

static void
intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connector)
{
        intel_attach_force_audio_property(connector);
        intel_attach_broadcast_rgb_property(connector);
}

void
intel_dp_init(struct drm_device *dev, int output_reg)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_connector *connector;
        struct intel_dp *intel_dp;
        struct intel_encoder *intel_encoder;
        struct intel_connector *intel_connector;
        const char *name = NULL;
        int type;

        intel_dp = kzalloc(sizeof(struct intel_dp), GFP_KERNEL);
        if (!intel_dp)
                return;

        intel_dp->output_reg = output_reg;
        intel_dp->dpms_mode = -1;

        intel_connector = kzalloc(sizeof(struct intel_connector), GFP_KERNEL);
        if (!intel_connector) {
                kfree(intel_dp);
                return;
        }
        intel_encoder = &intel_dp->base;

        if (HAS_PCH_SPLIT(dev) && output_reg == PCH_DP_D)
                if (intel_dpd_is_edp(dev))
                        intel_dp->is_pch_edp = true;

        if (output_reg == DP_A || is_pch_edp(intel_dp)) {
                type = DRM_MODE_CONNECTOR_eDP;
                intel_encoder->type = INTEL_OUTPUT_EDP;
        } else {
                type = DRM_MODE_CONNECTOR_DisplayPort;
                intel_encoder->type = INTEL_OUTPUT_DISPLAYPORT;
        }

        connector = &intel_connector->base;
        drm_connector_init(dev, connector, &intel_dp_connector_funcs, type);
        drm_connector_helper_add(connector, &intel_dp_connector_helper_funcs);

        connector->polled = DRM_CONNECTOR_POLL_HPD;

        if (output_reg == DP_B || output_reg == PCH_DP_B)
                intel_encoder->clone_mask = (1 << INTEL_DP_B_CLONE_BIT);
        else if (output_reg == DP_C || output_reg == PCH_DP_C)
                intel_encoder->clone_mask = (1 << INTEL_DP_C_CLONE_BIT);
        else if (output_reg == DP_D || output_reg == PCH_DP_D)
                intel_encoder->clone_mask = (1 << INTEL_DP_D_CLONE_BIT);

        if (is_edp(intel_dp))
                intel_encoder->clone_mask = (1 << INTEL_EDP_CLONE_BIT);

        intel_encoder->crtc_mask = (1 << 0) | (1 << 1);
        connector->interlace_allowed = true;

        connector->doublescan_allowed = 0;

        drm_encoder_init(dev, &intel_encoder->base, &intel_dp_enc_funcs,
                         DRM_MODE_ENCODER_TMDS);
        drm_encoder_helper_add(&intel_encoder->base, &intel_dp_helper_funcs);

        intel_connector_attach_encoder(intel_connector, intel_encoder);
        drm_sysfs_connector_add(connector);

        /* Set up the DDC bus. */
        switch (output_reg) {
                case DP_A:
                        name = "DPDDC-A";
                        break;
                case DP_B:
                case PCH_DP_B:
                        dev_priv->hotplug_supported_mask |=
                                HDMIB_HOTPLUG_INT_STATUS;
                        name = "DPDDC-B";
                        break;
                case DP_C:
                case PCH_DP_C:
                        dev_priv->hotplug_supported_mask |=
                                HDMIC_HOTPLUG_INT_STATUS;
                        name = "DPDDC-C";
                        break;
                case DP_D:
                case PCH_DP_D:
                        dev_priv->hotplug_supported_mask |=
                                HDMID_HOTPLUG_INT_STATUS;
                        name = "DPDDC-D";
                        break;
        }

        intel_dp_i2c_init(intel_dp, intel_connector, name);

        /* Cache some DPCD data in the eDP case */
        if (is_edp(intel_dp)) {
                bool ret;
                u32 pp_on, pp_div;

                pp_on = I915_READ(PCH_PP_ON_DELAYS);
                pp_div = I915_READ(PCH_PP_DIVISOR);

                /* Get T3 & T12 values (note: VESA not bspec terminology) */
                dev_priv->panel_t3 = (pp_on & 0x1fff0000) >> 16;
                dev_priv->panel_t3 /= 10; /* t3 in 100us units */
                dev_priv->panel_t12 = pp_div & 0xf;
                dev_priv->panel_t12 *= 100; /* t12 in 100ms units */

                ironlake_edp_panel_vdd_on(intel_dp);
                ret = intel_dp_get_dpcd(intel_dp);
                ironlake_edp_panel_vdd_off(intel_dp);
                if (ret) {
                        if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11)
                                dev_priv->no_aux_handshake =
                                        intel_dp->dpcd[DP_MAX_DOWNSPREAD] &
                                        DP_NO_AUX_HANDSHAKE_LINK_TRAINING;
                } else {
                        /* if this fails, presume the device is a ghost */
                        DRM_INFO("failed to retrieve link info, disabling eDP\n");
                        intel_dp_encoder_destroy(&intel_dp->base.base);
                        intel_dp_destroy(&intel_connector->base);
                        return;
                }
        }

        intel_encoder->hot_plug = intel_dp_hot_plug;

        if (is_edp(intel_dp)) {
                /* initialize panel mode from VBT if available for eDP */
                if (dev_priv->lfp_lvds_vbt_mode) {
                        dev_priv->panel_fixed_mode =
                                drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);
                        if (dev_priv->panel_fixed_mode) {
                                dev_priv->panel_fixed_mode->type |=
                                        DRM_MODE_TYPE_PREFERRED;
                        }
                }
                dev_priv->int_edp_connector = connector;
                intel_panel_setup_backlight(dev);
        }

        intel_dp_add_properties(intel_dp, connector);

        /* For G4X desktop chip, PEG_BAND_GAP_DATA 3:0 must first be written
         * 0xd.  Failure to do so will result in spurious interrupts being
         * generated on the port when a cable is not attached.
         */
        if (IS_G4X(dev) && !IS_GM45(dev)) {
                u32 temp = I915_READ(PEG_BAND_GAP_DATA);
                I915_WRITE(PEG_BAND_GAP_DATA, (temp & ~0xf) | 0xd);
        }
}