[Intel-gfx] [PATCH v3] drm/i915: Rework GPU reset sequence to match driver load & thaw

[Chris Wilson]

On Mon, Aug 25, 2014 at 10:18:09PM +0200, Daniel Vetter wrote:
> On Wed, Aug 20, 2014 at 04:56:41PM +0100, Chris Wilson wrote:
> > On Wed, Aug 20, 2014 at 03:21:55PM +0000, Mcaulay, Alistair wrote:
> > > It is not the same. This is a special case when re-initialising the hw. This flag is to allow gem_init_hw() to complete successfully during reset. 
> > > At any other point during reset, -EAGAIN should be returned.
> > 
> > Indeed. You've missed the point. Look closer at the reset counter and
> > reset ordering.
> 
> We could try to mark the gpu as reset again before starting the reinit to
> avoid this kludge. But that has the problem that if the ring init fails we
> have a bit a mess in marking the gpu terminally wedged. So I think overall
> not prettier than what we have here ... And if I'm mistaken I guess I can
> put on my idiot hat and merge the fixup ;-)

See other patches during the week. Marking the reset as complete after
performing the reset and before resuming the hardware is not ugly. If
the reset fails, you still have the wedge | in-progress. If the reset
succeeds but resume fails, you then have wedge | !in-progress.

Seriously read the request patch to see how it straightens out ring
access, full stop.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre