[PATCH i915 v3 1/2] i915: wait for fences in mmio_flip()

[Alexander Goins]

Sorry; needless to say I'm not super familiar with the Intel driver. ilk_do_mmio_flip() uses crtc->primary->fb to fetch the gem object:

         struct intel_framebuffer *intel_fb =
                 to_intel_framebuffer(intel_crtc->base.primary->fb);
         struct drm_i915_gem_object *obj = intel_fb->obj;

Given that, would it be okay for me to do the same?

Thanks,
Alex

-----Original Message-----
From: Chris Wilson [mailto:chris at chris-wilson.co.uk] 
Sent: Friday, November 13, 2015 2:46 AM
To: Daniel Stone
Cc: Alexander Goins; dri-devel; Daniel Vetter; Maarten Lankhorst
Subject: Re: [PATCH i915 v3 1/2] i915: wait for fences in mmio_flip()

On Fri, Nov 13, 2015 at 10:38:07AM +0000, Daniel Stone wrote:
> Hi,
> 
> On 13 November 2015 at 10:08, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > On Thu, Nov 12, 2015 at 05:49:28PM -0800, Alex Goins wrote:
> >>  static const uint32_t i8xx_primary_formats[] = { @@ -11170,10 
> >> +11172,19 @@ static void ilk_do_mmio_flip(struct intel_crtc 
> >> *intel_crtc)  static void intel_do_mmio_flip(struct intel_crtc 
> >> *intel_crtc)  {
> >>       struct drm_device *dev = intel_crtc->base.dev;
> >> +     struct drm_i915_gem_object *pending_flip_obj =
> >> +             intel_crtc->unpin_work->pending_flip_obj;
> >>       u32 start_vbl_count;
> >>
> >>       intel_mark_page_flip_active(intel_crtc);
> >>
> >> +     /* For framebuffer backed by dmabuf, wait for fence */
> >> +     if (pending_flip_obj->base.dma_buf) {
> >> +             reservation_object_wait_timeout_rcu(
> >> +                     pending_flip_obj->base.dma_buf->resv,
> >> +                     true, false, msecs_to_jiffies(96));
> >> +     }
> >
> > This wait should be prior to marking the flip as waiting for the 
> > flip-completion interrupt. My personal preference (aside from 
> > putting this next to the other wait) would to have been to use 
> > crtc->primary->fb to match the do_mmip_flips funcs (I expect that we 
> > will eliminate the pending_flip_obj in the near future).
> 
> No, don't use crtc->primary->fb for anything.

s/crtc->primary->fb/whatever is actually used by the ilk_do_mmio_flip and co which is certainly not pending_flip_obj/ -Chris

--
Chris Wilson, Intel Open Source Technology Centre