On 24-03-2026 02:49, Xaver Hugl wrote:
Have added the remaining error codes to the enum
drm_mode_atomic_err_code, will push as part of patchset 11.
I think it would be best to limit the enum values to actionable
things. Connector and scanout bandwidth sound useful and pretty
straight-forward to me, but the three other new values don't seem
useful for compositors at the moment.
DRM_MODE_ATTOMIC_PIPE_BW
Compositors aren't aware of pipes. What would they do with that information?
There are scenarios where two pipes driving a single connector, in that
case compositor will be informed on the unavailability of pipe, on the
other hand, if a given pipe scaler factor couldnt be supported due to
b/w limitation, that would fall into this category. The object pointer
would precisely convey the property causing this error.
DRM_MODE_ATOMIC_MEMORY_DOMAIN
DRM_MODE_ATOMIC_SPEC_VIOLOATION
I can't think of anything a compositor would do differently with these
vs. "unspecified_error".
Added this based on the feedback from
https://hackmd.io/f3bDn3kyRUalLn4LbMfCVQ#Commit-Failure-Feedback
As far as the enum INVALID_API_USAGE is concerned, there is a certain
understanding on the
usage of the atomic_ioctl, any miss in that would fall in this
category.
Invalid API usage would mean the compositor did something it can know
in advance is wrong based on the KMS API. It can't be used as the
default value.
Understand that it cant be a default error, will add another entry
DRM_MODE_ATOMIC_UNDEFINED_ERROR which would be the default one.
Some of them include
- Driver doesnt support atomic, but still atomic_ioctl being used
- Invalid/Junk flags
- Async flip not supported
- Flag page flip event along with test only is not supported
If changing this INVALID_API_USAGE to UNSPECIFIED_ERROR makes more
sense, I can change that.
No, they're two different things. We need both, and unspecified_error
needs to be the default for when the driver doesn't set anything more
specific.
Got it as commented above, will add DRM_MODE_ATOMIC_UNDEFINED_ERROR
which would be for default error.
Thanks and Regards,
Arun R Murthy
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- Xaver
