Re: [PATCH v10 0/7] User readable error codes on atomic_ioctl failure

["Murthy, Arun R" <arun.r.murthy@intel.com>]

On 24-02-2026 12:37, Ville Syrjälä wrote:
> On Mon, Feb 23, 2026 at 03:37:39PM +0530, Murthy, Arun R wrote:
>> Any other comments/feedback on this?
> Having random strings as uabi seems like a bad idea.
> How would you make sure those are never changed?
The requirement was to have a string for logging/debugging in the UMD 
logs and KMD/display to pass the verbose information.

Discussions around this.[1][2]

[1] https://hackmd.io/f3bDn3kyRUalLn4LbMfCVQ#Commit-Failure-Feedback

[2] https://patchwork.freedesktop.org/patch/666193/?series=152276&rev=1

Thanks and Regards,
Arun R Murthy
-------------------

>> Thanks and Regards,
>> Arun R Murthy
>> -------------------
>>
>> On 23-02-2026 14:45, Arun R Murthy wrote:
>>> EDITME: Imported from f20260210-atomic-v9-5-525c88fd2402@intel.com
>>>           Please review before sending.
>>>
>>> The series focuses on providing a user readable error value on a failure
>>> in drm_atomic_ioctl(). Usually -EINVAL is returned in most of the error
>>> cases and it is difficult for the user to decode the error and get to
>>> know the real cause for the error. If user gets to know the reason for
>>> the error then corrective measurements can be taken up.
>>>
>>> User will have to check for the capability
>>> DRM_CAP_ATOMIC_ERROR_REPORTING before using this feature so as to ensure
>>> that the driver supports failure reporting.
>>>
>>> TODO: driver specific error codes are to be added and will be done in
>>> the follow-up patches.
>>>
>>> TODO: Once the series is merged the element 'reserved' used for sending
>>> the failure code in struct drm_mode_atomic is to changed to err_code.
>>>
>>> The IGT related changes are pushed for review @
>>> https://patchwork.freedesktop.org/series/153330/
>>>
>>> [RFC] changes for libdrm pushed for review @
>>> https://gitlab.freedesktop.org/mesa/libdrm/-/merge_requests/450
>>>
>>>       To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>>>       To: suraj.kandpal@intel.com>
>>>       To: Maxime Ripard <mripard@kernel.org>
>>>       To: Thomas Zimmermann <tzimmermann@suse.de>
>>>       To: David Airlie <airlied@gmail.com>
>>>       To: Simona Vetter <simona@ffwll.ch>
>>>       To: Jani Nikula <jani.nikula@linux.intel.com>
>>>       To: Rodrigo Vivi <rodrigo.vivi@intel.com>
>>>       To: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
>>>       To: Tvrtko Ursulin <tursulin@ursulin.net>
>>>       To: xaver.hugl@kde.org
>>>       To: harry.wentland@amd.com
>>>       To: uma.shankar@intel.com
>>>       To: louis.chauvet@bootlin.com
>>>       To: naveen1.kumar@intel.com
>>>       To: ramya.krishna.yella@intel.com
>>>       Cc: dri-devel@lists.freedesktop.org
>>>       Cc: intel-gfx@lists.freedesktop.org
>>>       Cc: intel-xe@lists.freedesktop.org
>>>       Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
>>>
>>> Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
>>> ---
>>> Changes in v9:
>>> - EDITME: describe what is new in this series revision.
>>> - EDITME: use bulletpoints and terse descriptions.
>>> - Link to v8: https://lore.kernel.org/r/20260129-atomic-v8-0-4cb7b0faa051@intel.com
>>>
>>> ---
>>> Arun R Murthy (7):
>>>         drm: Define user readable error codes for atomic ioctl
>>>         drm/atomic: Add error_code element in atomic_state
>>>         drm/atomic: Call complete_signaling only if prepare_signaling is done
>>>         drm/atomic: Allocate atomic_state at the beginning of atomic_ioctl
>>>         drm/atomic: Return user readable error in atomic_ioctl
>>>         drm/i915/display: Error codes for async flip failures
>>>         drm: Introduce DRM_CAP_ATOMIC_ERROR_REPORTING
>>>
>>>    drivers/gpu/drm/drm_atomic.c                 | 31 ++++++++++
>>>    drivers/gpu/drm/drm_atomic_uapi.c            | 89 ++++++++++++++++++++--------
>>>    drivers/gpu/drm/drm_ioctl.c                  |  3 +
>>>    drivers/gpu/drm/i915/display/intel_display.c | 25 ++++----
>>>    include/drm/drm_atomic.h                     | 10 ++++
>>>    include/uapi/drm/drm.h                       |  7 +++
>>>    include/uapi/drm/drm_mode.h                  | 37 ++++++++++++
>>>    7 files changed, 165 insertions(+), 37 deletions(-)
>>> ---
>>> base-commit: cec43d5c2696af219fc2ef71dd7e93db48c80f66
>>> change-id: 20250728-atomic-c9713fd357e4
>>>
>>> Best regards,