Re: drm: GPF in drm_getcap

From: Michel DÃnzer
Date: Mon Nov 28 2016 - 02:14:25 EST


On 28/11/16 03:55 PM, Daniel Vetter wrote:
> On Sat, Nov 26, 2016 at 7:22 PM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote:
>> On Sat, Nov 26, 2016 at 7:07 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
>>> grep "card0" dmesg:
>>> [ 5.298617] device: 'card0': device_add
>>> [ 5.298946] PM: Adding info for No Bus:card0
>>> [ 6.436178] device: 'card0': device_add
>>> [ 6.436488] PM: Adding info for No Bus:card0
>>>
>>>
>>> # ls -l /dev/dri/card0
>>> crw-rw---T 1 root video 226, 0 Nov 26 18:05 /dev/dri/card0
>>>
>>> # ls -lt /sys/class/drm/card0/device/
>>> ls: cannot access /sys/class/drm/card0/device/: No such file or directory
>>>
>>> # ls -lt /sys/class/drm/card0/device/driver
>>> ls: cannot access /sys/class/drm/card0/device/driver: No such file or directory
>>
>> Looks like vgem. Something like this should help:
>>
>> https://gist.github.com/dvdhrm/1bcdf4f3485aa1614a0198a7b90515e2
>>
>> I wonder whether it would be more appropriate to return -ENOTSUPP rather than 0.

Can't see how that would matter FWIW.


> Seems a bit overkill, but can't hurt. This is most likely a
> regression, probably introduced in
>
> commit f837297ad82480024d3ad08cd84f6670bcafa862
> Author: Michel DÃnzer <michel.daenzer@xxxxxxx>
> Date: Mon Aug 8 16:23:39 2016 +0900
>
> drm: Add DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE/RELATIVE flags v2
>
> Michel, can you pls take care of this? Either with a minimal fix, or
> by adopting David's patch?

Can't we just use David's patch as-is? If not, I think Dmitry or someone
else would be better equipped than me to extract a minimal fix from it
and test it.


--
Earthling Michel DÃnzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer