[Intel-gfx] [PATCH] drm/i915: Officially give up on seqno coherency

[Chris Wilson]

On Fri, Jun 19, 2015 at 09:16:09PM +0200, Daniel Vetter wrote:
> We've never figured out the magic trick to make irq vs. seqno
> updates coherent, only tricks to make it work. And since
> 
> commit 094f9a54e35500739da185cdb78f2e92fc379458
> Author: Chris Wilson <chris at chris-wilson.co.uk>
> Date:   Wed Sep 25 17:34:55 2013 +0100
> 
>     drm/i915: Fix __wait_seqno to use true infinite timeouts
> 
> we automatically fall back to an irq augmented with polling scheme
> after the first missed interrupt. There's really nothing else we can
> do, hence tune down the message to informational level. It's still
> useful for users in case it reliable preceedes a hard system hang.
> 
> v2: Use NOTICE since it might be of value for bug reports (Chris).
> 
> Cc: Mark Janes <mark.a.janes at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: stable at vger.kernel.org
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>

Now all we need to is to save the GPU state to the pstore in the
picoseconds before a hard hang, and we'll be sorted.

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre