ACK: [SRU][R][PATCH 00/13] Export IP discovery even if amdgpu probe fails

[Benjamin Wheeler]

Acked-by: Benjamin Wheeler <benjamin.wheeler at canonical.com>

On Mon, Jul 6, 2026 at 2:45 AM Yo-Jung Leo Lin (AMD) via kernel-team <
kernel-team at lists.ubuntu.com> wrote:

> BugLink: https://bugs.launchpad.net/bugs/2158690
>
> [ Impact ]
>
> The amdgpu probing sequence can fail for any multitude of reasons (missing
> firmware, missing NPI support, unexpected hardware response).
>
> Ideally; we would have all NPI support in Ubuntu at product launch, but
> due to kernel schedule this isn't always feasible; particularly for dGPUs.
>
> For missing NPI support on dGPU specifically we want to be able to
> identify the system though so that we can potentially offer DKMS package
> from amdgpu-install script.
>
> To support this need there are changes introduced that will export IP
> discovery information to userspace even during probe failure.
>
> [ Fix ]
>
> The major patchsets are:
>
> 1. drm/amdgpu: Export ip_discovery sysfs on probe failure[1]: in
> linux-next 402e04f11ff7
> 2. drm/amdgpu: clean up discovery and preempt sysfs entries on
> shutdown[2]: in linux-next 7de02fe95312
> 3. drm/amdgpu: don't free standalone ip_discovery sysfs in sysfs_fini[3]:
> in linux-next 26373c719455
>
> And their dependent patches. See additional information.
>
> [ Test plan ]
>
> On APU/dGPU already supported by Ubuntu out-of-the-box:
>
>     1) Remove a GPU firmware from /lib/firmware.
>     2) Reboot system
>     3) Verify amdgpu shows probe error
>     4) Verify that IP discovery info in sysfs
>     5) Unload amdgpu
>     6) Restore GPU firmware
>     7) reload amdgpu
>     8) Verify works
>
> On new APU/dGPU
>
>    1) Verify amdgpu shows probe error
>    2) Verify that IP discovery info in sysfs
>
> [ Where problems could occur]
>
> This changes
>
> Bug in this likely leads to 1) handling of probe failure and 2) module
> unload/reload behavior and 3) internal implementation of sysfs files under
> ip_discovery.
>
> For 1), if a probe fails then the gpu drivers is already in the bad state.
> This at least leave more postmoterm information that we can revisit.
>
> For 2), use cases that need active unload/load the module when system is
> up and running may be impacted, which is likely rare.
>
> For 3), tools relying on those sysfs files may be impacted.
>
> [ Additional information ]
>
> [1]
> https://lore.kernel.org/amd-gfx/20260406212442.2321667-1-mario.limonciello@amd.com/
> [2]
> https://lore.kernel.org/amd-gfx/20260616091444.25605-1-geoffrey.mcrae@amd.com/
> [3]
> https://lore.kernel.org/amd-gfx/20260622161914.1648195-1-mario.limonciello@amd.com/
>
> The full patch list to support this on 7.0-based kernel:
>
> ```
> drm/amdgpu: don't free standalone ip_discovery sysfs in sysfs_fini
> drm/amdgpu: clean up discovery and preempt sysfs entries on shutdown
> drm/amdgpu: Export ip_discovery sysfs on probe failure
> drm/amdgpu: Fix discovery offset check under VF
> drm/amdgpu: fix IP discovery v0 handling
> drm/amdgpu: Add size guard before copy discovery binary
> drm/amdgpu: use DISCOVERY_TMR_SIZE in ACPI TMR fallback
> drm/amdgpu: Avoid NULL dereference in discovery topology coredump path v3
> drm/amdgpu: fallback to default discovery offset/size in sriov guest
> drm/amdgpu: New interface to get IP discovery binary v3
> drm/amdgpu/discovery: use common function to check discovery table
> drm/amdgpu/discovery: support new discovery binary header
> drm/amdgpu: include ip discovery data in devcoredump
> ```
>
> Feifei Xu (1):
>   drm/amdgpu: Add size guard before copy discovery binary
>
> Hawking Zhang (2):
>   drm/amdgpu: New interface to get IP discovery binary v3
>   drm/amdgpu: fallback to default discovery offset/size in sriov guest
>
> Jesse.Zhang (1):
>   drm/amdgpu: use DISCOVERY_TMR_SIZE in ACPI TMR fallback
>
> Lijo Lazar (1):
>   drm/amdgpu: Fix discovery offset check under VF
>
> Likun Gao (2):
>   drm/amdgpu/discovery: support new discovery binary header
>   drm/amdgpu/discovery: use common function to check discovery table
>
> Mario Limonciello (2):
>   drm/amdgpu: Export ip_discovery sysfs on probe failure
>   drm/amdgpu: don't free standalone ip_discovery sysfs in sysfs_fini
>
> Pierre-Eric Pelloux-Prayer (1):
>   drm/amdgpu: include ip discovery data in devcoredump
>
> Srinivasan Shanmugam (1):
>   drm/amdgpu: Avoid NULL dereference in discovery topology coredump path
>     v3
>
> filippor (1):
>   drm/amdgpu: fix IP discovery v0 handling
>
> geomcrae_amdeng (1):
>   drm/amdgpu: clean up discovery and preempt sysfs entries on shutdown
>
>  .../gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c  |   2 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c    |   5 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 814 ++++++++++++------
>  drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.h |  10 +
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c       |   2 +
>  .../gpu/drm/amd/amdgpu/amdgpu_preempt_mgr.c   |  14 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h       |   1 +
>  drivers/gpu/drm/amd/include/discovery.h       |  13 +
>  8 files changed, 618 insertions(+), 243 deletions(-)
>
> --
> 2.43.0
>
>
> --
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team
>
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