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 14:16, Ville Syrjälä wrote:
> On Tue, Feb 24, 2026 at 12:46:10PM +0530, Murthy, Arun R wrote:
>> 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
> So the enum+obj_id thing there is perhaps the only thing that makes
> sense for compositors.
>
> Although I kinda doubt its actual usefulness to drive useful
> fallback logic because often the restrictions might be a combination
> of many things, and the kernel can only realistically report one of
> those things.
>
> Anyways, someone really needs to do the actual compositor
> implementation so that we could see how any of this would
> even work in practice.
Xaver is working on the compositor implementation for KWin and has 
commented[3] that the API looks good.


[3] https://patchwork.freedesktop.org/patch/696982/?series=152275&rev=6
Thanks and Regards,
Arun R Murthy
-------------------

>> 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,