[PATCH] drm/nouveau: check ioctl command codes better

[Danilo Krummrich]

On 7/22/25 12:52 PM, Arnd Bergmann wrote:
> On Tue, Jul 22, 2025, at 12:29, Chris Bainbridge wrote:
>> On Mon, Jul 21, 2025 at 08:22:48AM -0400, Satadru Pramanik wrote:
>>> Hello all,
>>>
>>> I suspect this commit in 6.16-rc7 has broken acceleration with Mesa's
>>> nouveau drivers on my machine.

Thanks for the report!

Please make sure to keep maintainers in the loop, for some reason I was removed
from the recipient list for this regression report.

>>>
>>> glxinfo -B reports that I'm using llvmpipe.
>>>
>>> Reverting this in 6.16-rc7 restores nouveau acceleration, and glxinfo
>>> then reports: "OpenGL renderer string: NVE7"
>>
>> I also bisected an issue to this commit. On my laptop, this commit
>> results in an intermittent desktop crash (Xorg segfault) when changing
>> display scale, which can be more reliably reproduced with:
>>
>> for x in {1..100}; do
>>    xrandr --output eDP-1 --mode 2560x1600 --scale 0.5 --filter nearest
>>    xrandr --output eDP-1 --mode 2560x1600 --scale 1 --filter nearest
>> done
>>
> 
> I won't have time to work on fixing my patch before the merge window,
> let's just revert it.

@Arnd: Yes, given the short timeframe I think that's the best. Can you please 
send the revert?