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

[Daniel Vetter]

On Fri, Nov 13, 2015 at 07:38:21PM +0000, Alexander Goins wrote:
> 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?

I think so, since this is the legacy page_flip. Which will hopefully
disappear real soon now ...
-Daniel

> 
> 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
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch