Similar to commit 49b20dbf74 ("drm/i915/gt: Perform an arbitration
check before busywaiting"), also add a check prior to the busywait
on gen8+, as we have now seen (because we added a selftest to add fault
injection into the engine resets) the same engine reset failure leading
to an indefinite wait on the ring-stop semaphore. So not a Tigerlake
specific bug after all, though it still seems odd behaviour for the
busywait as we do get the arbitration point elsewhere on a miss.
Testcase: igt_reset_fail_engine
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210117110418.3361-1-chris@chris-wilson.co.uk
During igt_reset_nop_engine, it was observed that an unexpected failed
engine reset lead to us busywaiting on the stop-ring semaphore (set
during the reset preparations) on the first request afterwards. There was
no explicit MI_ARB_CHECK in this sequence as the presumption was that
the failed MI_SEMAPHORE_WAIT would itself act as an arbitration point.
It did not in this circumstance, so force it.
This patch is based on the assumption that the MI_SEMAPHORE_WAIT failure
to arbitrate is a rare Tigerlake bug, similar to the lite-restore vs
semaphore issues previously seen in the CS. The explicit MI_ARB_CHECK
should always ensure that there is at least one arbitration point in the
request before the MI_SEMAPHORE_WAIT to trigger the IDLE->ACTIVE event.
Upon processing that event, we will clear the stop-ring flag and release
the semaphore from its busywait.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210112100759.32698-2-chris@chris-wilson.co.uk
On the off chance that we need to arbitrate before launching the
payload, perform the check after we signal the request is ready to
start. Assuming instantaneous processing of the CS event, the request
will then be treated as having started when we make the decisions as to
how to process that CS event.
v2: More commentary about the users of i915_request_started() as a
reminder about why we are marking the initial breadcrumb.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210112100759.32698-1-chris@chris-wilson.co.uk
If a request is submitted and known to require no preemption, disable
arbitration around the batch which prevents the HW from handling a
preemption request during the payload.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210108204026.20682-7-chris@chris-wilson.co.uk
Split the definition, construction and updating of the Logical Ring
Context from the execlist submission interface. The LRC is used by the
HW, irrespective of our different submission backends.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201219020343.22681-1-chris@chris-wilson.co.uk
These functions are independent from the backend used and can therefore
be split out of the exelists submission file, so they can be re-used by
the upcoming GuC submission backend.
Based on a patch by Chris Wilson.
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201209233618.4287-3-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
