Re: [PATCH 2/2] drm/i915: Assert we hold the CRTC powerwell for generating vblank interrupts

Maarten Lankhorst
2016-10-10T09:35:09Z

Op 07-10-16 om 21:49 schreef Chris Wilson:
> To enable the vblank itself, we need to have an RPM wakeref for the mmio
> access, and whilst generating the vblank interrupts we continue to
> require the rpm wakeref. The assumption is that the RPM wakeref is held
> by the display powerwell held by the active pipe. As this chain was not
> obvious to me chasing the drm_wait_vblank ioctl, document it with a WARN
> during *_vblank_enable().
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Don't we prevent enabling the vblank irq through drm_crtc_vblank_on/off?

I'd rather not have things look at crtc->state if possible, locking might not help you.

~Maarten