[Nouveau] [PATCH] drm/nouveau: set irq_enabled manually

[Daniel Vetter]

On Thu, Jan 30, 2014 at 12:11:30PM -0500, Ilia Mirkin wrote:
> On Thu, Jan 30, 2014 at 3:33 AM, Daniel Vetter <daniel at ffwll.ch> wrote:
> > On Thu, Jan 30, 2014 at 1:53 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> >> Since commit 0fa9061ae8c ("drm/nouveau/mc: handle irq-related setup
> >> ourselves"), drm_device->irq_enabled remained unset. This is needed in
> >> order to properly wait for a vblank event in the generic drm code.
> >>
> >> See https://bugs.freedesktop.org/show_bug.cgi?id=74195
> >>
> >> Reported-by: Jan Janecek <janjanjanx at gmail.com>
> >> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
> >> Cc: stable at vger.kernel.org # 3.10+
> >> ---
> >>
> >> TBH, not sure why this fixes things, as irq_enabled == false should have
> >> caused the vblank wait to not wait, since the condition would be
> >> immediately true.
> >>
> >> Jan, mind double-checking that this version of the patch fixes things
> >> for you? Not 100% sure where you stuck the irq_enabled=true line when you
> >> tried it out.
> >
> > The core drm vblank code bails out if dev->irq_enabled isn't set. So
> 
> Right. And what I'm unclear on is how does bailing out on vblank wait
> cause the originally reported issue -- sluggishness. That seems to
> imply that one is waiting too long rather than not waiting enough.

Hm, that's indeed fairly strange. No idea how this can come about tbh.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch