[Intel-gfx] [PATCH 0/6] drm/i915: Avoid stuck page flip waiters on GPU reset

[Daniel Vetter]

On Tue, Jan 29, 2013 at 05:39:46PM +0100, Daniel Vetter wrote:
> On Tue, Jan 29, 2013 at 06:13:32PM +0200, ville.syrjala at linux.intel.com wrote:
> > Someone mentioned on irc that intel_crtc_wait_for_pending_flips() was
> > getting stuck in some cases. This rang a bell since I was poking around
> > that stuff last year.
> > 
> > The issue that I'm trying to fix here is processes getting stuck in D
> > state when a GPU reset happens while page flips have been scheduled.
> > 
> > Testing is easy 1) fire up 'glxgears -fullscreen', run 'gem_hang 0',
> > try to VT switch. Without this series X and some kworker soon get stuck
> > in D state and you're left with a useless box. With the patch set, you
> > wait a while, the GPU hangcheck kicks in, and you get your console back.
> 
> Broken record maintainer request: Can you please bake that into an i-g-t?
> I think (hope) that running one of the delayed flip tests vs. the hangman
> (gem_hang is a bit evil since it can kill boxes for real) should do the
> trick. Then maybe also run one of the wf-vblank tests vs. hangman to check
> that we cancel those correctly, too.

Actually for the case you're fixing here we probably need a delayed flip
vs. modeset (without flip event checks) against a simulated gpu hang.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch