Re: [PATCH] drm/i915: Try enabling RC6 by default (again)

[Ted Phelps <phelps@gnusto.com>]

Daniel Vetter writes:
> On Thu, Aug 4, 2011 at 16:05, Ted Phelps <phelps@gnusto.com> wrote:
> > I saw a bunch of stack traces like the one below, alternating between
> > ring_put and ring_get, before the GPU was declared wedged.
> 
> How much time happens between the first wait_for_fifo backtrace and
> the final gpu hang report?

About 6 seconds.  All 20 ring_put/ring_get failures happen in the same
second, then there's a 4 second pause before the GPU is first declared
hung, and another couple of seconds before the GPU is declared wedged:

Aug  4 23:37:02 orpheus kernel: ------------[ cut here ]------------
...
Aug  4 23:37:06 orpheus kernel: [drm:i915_hangcheck_elapsed] *ERROR* Hangcheck timer elapsed... GPU hung
...
Aug  4 23:37:08 orpheus kernel: [drm:i915_reset] *ERROR* GPU hanging too fast, declaring wedged!
Aug  4 23:37:08 orpheus kernel: [drm:i915_reset] *ERROR* Failed to reset chip.


> If it's short (order of a second or less) can you rehang your gpu with
> kernel log timestamping switched on?

I'm happy to re-hang the GPU with kernel log timestamping enabled, but I
won't be able to do so until Sunday night.

Cheers,
-Ted