[Intel-gfx] [PATCH 2/2] drm/i915: Wait for pending flips in intel_pipe_set_base()

[Chris Wilson]

On Wed, 31 Oct 2012 19:38:41 +0200, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> intel_pipe_set_base() never actually waited for any pending page flips
> on the CRTC. It looks like it tried to, by calling intel_finish_fb() on
> the current front buffer. But the pending flips were actually tracked
> in the BO of the previous front buffer, so the call to intel_finish_fb()
> never did anything useful.
> 
> Now even the pending_flip counter is gone, so we should just
> use intel_crtc_wait_for_pending_flips(), but since we're already holding
> struct_mutex when we would call that function, we need another version
> of it, that itself doesn't lock struct_mutex.

That function call is now superfluous as you pointed out in an earlier
review...

But yes, not waking up the pending_flip_queue after a GPU hang is a
recent bug, and could explain the lockup in
https://bugs.freedesktop.org/show_bug.cgi?id=56337.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre