On Wed, Dec 05, 2012 at 04:35:59PM +0000, Damien Lespiau wrote: > On Thu, Nov 15, 2012 at 4:17 PM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote: > > + * Note: It is of utmost importance that the passed in seqno and reset_counter > > + * values have been read by the caller in an smb safe manner. Where read-side > > smp? > > > + * locks are involved, it is sufficient to read the reset_counter before > > + * unlocking the lock that protects the seqno. For lockless tricks, the > > + * reset_counter _must_ be read before, and an appropriate smb_rmb must be > > smp_rmb()? > > > if (!i915_reset(dev)) { > > - atomic_set(&error->reset_counter, 0); > > kobject_uevent_env(&dev->primary->kdev.kobj, KOBJ_CHANGE, reset_done_event); > > } else { > > atomic_set(&error->reset_counter, I915_WEDGED); > > } > > > > + /* > > + * After all the gem state is reset, increment the reset counter > > + * and wake up everyone waiting for the reset to complete. > > + * > > + * Since unlock operations are a one-sided barrier only, we need > > + * to insert a barrier here to order any seqno updates before > > + * the counter increment. > > + */ > > + smp_mb__before_atomic_inc(); > > + atomic_inc(&dev_priv->gpu_error.reset_counter); > > It seems that if the GPU can't reset, reset_counter is set to > I915_WEDGED ie 0xffffffff and we increment that to 0? I've somehow totally lost track of this series here. I've now slurped in the first four patches up to "drm/i915: clear up wedged transitions". Can you please take a look at the two follow-up patches I've posted in reply to your mail and smash and r-b onto them if you approve? Thanks, Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch