linux/Documentation/scsi/lpfc.rst
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   1.. SPDX-License-Identifier: GPL-2.0
   2
   3=========================
   4LPFC Driver Release Notes
   5=========================
   6
   7
   8.. important::
   9
  10  Starting in the 8.0.17 release, the driver began to be targeted strictly
  11  toward the upstream kernel. As such, we removed #ifdefs for older kernels
  12  (pre 2.6.10). The 8.0.16 release should be used if the driver is to be
  13  run on one of the older kernels.
  14
  15  The proposed modifications to the transport layer for FC remote ports
  16  and extended attribute support is now part of the upstream kernel
  17  as of 2.6.12. We no longer need to provide patches for this support,
  18  nor a *full* version which has old an new kernel support.
  19  
  20  The driver now requires a 2.6.12 (if pre-release, 2.6.12-rc1) or later
  21  kernel.
  22  
  23  Please heed these dependencies....
  24
  25
  26The following information is provided for additional background on the
  27history of the driver as we push for upstream acceptance.
  28
  29Cable pull and temporary device Loss:
  30
  31  In older revisions of the lpfc driver, the driver internally queued i/o 
  32  received from the midlayer. In the cases where a cable was pulled, link
  33  jitter, or a device temporarily loses connectivity (due to its cable
  34  being removed, a switch rebooting, or a device reboot), the driver could
  35  hide the disappearance of the device from the midlayer. I/O's issued to
  36  the LLDD would simply be queued for a short duration, allowing the device
  37  to reappear or link come back alive, with no inadvertent side effects
  38  to the system. If the driver did not hide these conditions, i/o would be
  39  errored by the driver, the mid-layer would exhaust its retries, and the
  40  device would be taken offline. Manual intervention would be required to
  41  re-enable the device.
  42
  43  The community supporting kernel.org has driven an effort to remove
  44  internal queuing from all LLDDs. The philosophy is that internal
  45  queuing is unnecessary as the block layer already performs the 
  46  queuing. Removing the queues from the LLDD makes a more predictable
  47  and more simple LLDD.
  48
  49  As a potential new addition to kernel.org, the 8.x driver was asked to
  50  have all internal queuing removed. Emulex complied with this request.
  51  In explaining the impacts of this change, Emulex has worked with the
  52  community in modifying the behavior of the SCSI midlayer so that SCSI
  53  devices can be temporarily suspended while transport events (such as
  54  those described) can occur.  
  55
  56  The proposed patch was posted to the linux-scsi mailing list. The patch
  57  is contained in the 2.6.10-rc2 (and later) patch kits. As such, this
  58  patch is part of the standard 2.6.10 kernel.
  59
  60  By default, the driver expects the patches for block/unblock interfaces
  61  to be present in the kernel. No #define needs to be set to enable support.
  62
  63
  64Kernel Support
  65==============
  66
  67  This source package is targeted for the upstream kernel only. (See notes
  68  at the top of this file). It relies on interfaces that are slowing
  69  migrating into the kernel.org kernel.
  70
  71  At this time, the driver requires the 2.6.12 (if pre-release, 2.6.12-rc1)
  72  kernel.
  73
  74  If a driver is needed for older kernels please utilize the 8.0.16
  75  driver sources.
  76
  77
  78Patches
  79=======
  80
  81  Thankfully, at this time, patches are not needed.
  82