* drm: understanding the kernel warning during drm_vblank_cleanup()
@ 2018-11-29 14:30 Ahsan Hussain
2018-11-29 15:19 ` Ville Syrjälä
0 siblings, 1 reply; 2+ messages in thread
From: Ahsan Hussain @ 2018-11-29 14:30 UTC (permalink / raw)
To: dri-devel; +Cc: linux-kernel
Hi folks,
I'm new to DRM and trying to understand the warning in
drivers/gpu/drm/drm_vblank.c during drm_vblank_cleanup().
WARN_ON(READ_ONCE(vblank->enabled) &&
drm_core_check_feature(dev, DRIVER_MODESET));
Is the drm driver responsible for making sure that !(vblank->enabled) in
the .unbind operation, or is this something related to userspace? What
does the warning signify? Git history did not help here at all.
Regards,
Ahsan.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: drm: understanding the kernel warning during drm_vblank_cleanup()
2018-11-29 14:30 drm: understanding the kernel warning during drm_vblank_cleanup() Ahsan Hussain
@ 2018-11-29 15:19 ` Ville Syrjälä
0 siblings, 0 replies; 2+ messages in thread
From: Ville Syrjälä @ 2018-11-29 15:19 UTC (permalink / raw)
To: Ahsan Hussain; +Cc: dri-devel, linux-kernel
On Thu, Nov 29, 2018 at 07:30:45PM +0500, Ahsan Hussain wrote:
> Hi folks,
>
> I'm new to DRM and trying to understand the warning in
> drivers/gpu/drm/drm_vblank.c during drm_vblank_cleanup().
>
> WARN_ON(READ_ONCE(vblank->enabled) &&
> drm_core_check_feature(dev, DRIVER_MODESET));
>
> Is the drm driver responsible for making sure that !(vblank->enabled) in
> the .unbind operation, or is this something related to userspace? What
> does the warning signify? Git history did not help here at all.
It signifies you haven't cleaned up things properly. Usually what
you would do is call drm_atomic_helper_shutdown() which will also
end up turnng vblank interrupts off, assuming you use
drm_vblank_on()/off() properly.
--
Ville Syrjälä
Intel
^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-11-29 14:30 drm: understanding the kernel warning during drm_vblank_cleanup() Ahsan Hussain
2018-11-29 15:19 ` Ville Syrjälä
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