On Wed, Nov 04, 2015 at 11:33:04AM +0200, Mika Kuoppala wrote: > We have a timed release of a forcewake when using > I915_READ/WRITE macros. wait_for() macro will go to quite > long sleep if the first read doesn't satisfy the condition for > successful exit. With these two interacting, it is possible that > we lose the forcewake during the wait_for() and the subsequent read > will reaquire forcewake. > > Further experiments with skl shows that when we lose forcewake, > we lose the reset request we submitted. So this register > is not power context saved. > > Grab forcewakes for all engines before starting to request for > resets so that all requests stay valid for the duration of reset > requisition across all the engines. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92774 > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Tested-by: Tomi Sarvela <tomix.p.sarvela@xxxxxxxxx> > Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_uncore.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c > index f0f97b2..5a6e7f1b 100644 > --- a/drivers/gpu/drm/i915/intel_uncore.c > +++ b/drivers/gpu/drm/i915/intel_uncore.c > @@ -1483,6 +1483,8 @@ static int gen8_do_reset(struct drm_device *dev) > struct intel_engine_cs *engine; > int i; > /* If the power well sleeps during the reset, the reset * request may be dropped and never completes (causing -EIO). */ > + intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL); I wonder if this would be more useful in intel_gpu_reset(), it won't hurt any other platforms and may prevent similar snafu in future? -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
