Public bug reported:

[ Impact ]

Some AMD platforms prefer letting BIOS handling what are supposed to be
done by the PMF kernel driver. On those platforms, the BIOS should take
full control over the relevant functions, without the interference from
the PMF driver. To achieve this, add quirks that make the PMF driver
fail to probe on those platforms.


[ Test Plan ]

1. Install the kernel on one of those platforms.
2. Boot into the kernel.
3. Check dmesg. It should show "Platform prefers BIOS over PMF module. Finish 
PMF driver probe early."


[ Where problems could occur ]

If the quirk matches the wrong platform, PMF driver will not function.


[ Other Information ]

Simply making the driver fail to probe would suffice. This is because
BIOS detects the presence of the PMF driver by detecting regular
heartbeat signal sent from the driver. If BIOS detects no such
heartbeats, it'll consider the PMF driver missing, and will
automatically take over the relevant functions.

** Affects: hwe-next
     Importance: Undecided
         Status: New

** Affects: linux-oem-6.11 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: jira-delta-85 oem-priority

** Tags added: jira-delta-85 oem-priority

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Packages, which is subscribed to linux-oem-6.11 in Ubuntu.
https://bugs.launchpad.net/bugs/2091847

Title:
  Prefer BIOS over PMF on some AMD platforms

Status in HWE Next:
  New
Status in linux-oem-6.11 package in Ubuntu:
  New

Bug description:
  [ Impact ]

  Some AMD platforms prefer letting BIOS handling what are supposed to
  be done by the PMF kernel driver. On those platforms, the BIOS should
  take full control over the relevant functions, without the
  interference from the PMF driver. To achieve this, add quirks that
  make the PMF driver fail to probe on those platforms.

  
  [ Test Plan ]

  1. Install the kernel on one of those platforms.
  2. Boot into the kernel.
  3. Check dmesg. It should show "Platform prefers BIOS over PMF module. Finish 
PMF driver probe early."

  
  [ Where problems could occur ]

  If the quirk matches the wrong platform, PMF driver will not function.

  
  [ Other Information ]

  Simply making the driver fail to probe would suffice. This is because
  BIOS detects the presence of the PMF driver by detecting regular
  heartbeat signal sent from the driver. If BIOS detects no such
  heartbeats, it'll consider the PMF driver missing, and will
  automatically take over the relevant functions.

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