[Intel-gfx] [PATCH] drm/i915: Fix current fb blocking for page flip.

[Jesse Barnes]

On Thu, 21 Oct 2010 17:55:13 +0800
Chia-I Wu <olvaffe at gmail.com> wrote:

> Hi list,
> 
> According to the doc for page_flip, intel_crtc_page_flip should
> 
>    ... block all rendering to the current fb until the flip has
>    completed.
> 
> I am not entirely sure, but it seems that it is
> work->old_fb_obj->pending_flip that needs to be incremented instead of
> work->pending_flip_obj->pending_flip.  This patch does fix the
> rendering artifacts with my Android on i915 project.  Any thought?

In intel_crtc_page_flip()?  It *looks* like incrementing the flip count
for the fb passed into the routine is the right thing to do; we want to
make sure the fb passed in isn't used again until its flip is complete.

But maybe we're decrementing it incorrectly in the buffer exec path or
allowing rendering to continue too soon?

-- 
Jesse Barnes, Intel Open Source Technology Center