drm/i915/execlists: Flush pending preemption events during reset

Catch up with the inflight CSB events, after disabling the tasklet
before deciding which request was truly guilty of hanging the GPU.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
CC: Michel Thierry <michel.thierry@intel.com>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180516183355.10553-7-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2018-05-16 19:33:54 +01:00
parent 73377dbcc7
commit 63572937ce

View file

@ -1844,6 +1844,7 @@ static struct i915_request *
execlists_reset_prepare(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct i915_request *request, *active;
GEM_TRACE("%s\n", engine->name);
@ -1858,7 +1859,40 @@ execlists_reset_prepare(struct intel_engine_cs *engine)
*/
__tasklet_disable_sync_once(&execlists->tasklet);
return i915_gem_find_active_request(engine);
/*
* We want to flush the pending context switches, having disabled
* the tasklet above, we can assume exclusive access to the execlists.
* For this allows us to catch up with an inflight preemption event,
* and avoid blaming an innocent request if the stall was due to the
* preemption itself.
*/
if (test_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted))
process_csb(engine);
/*
* The last active request can then be no later than the last request
* now in ELSP[0]. So search backwards from there, so that if the GPU
* has advanced beyond the last CSB update, it will be pardoned.
*/
active = NULL;
request = port_request(execlists->port);
if (request) {
unsigned long flags;
spin_lock_irqsave(&engine->timeline.lock, flags);
list_for_each_entry_from_reverse(request,
&engine->timeline.requests,
link) {
if (__i915_request_completed(request,
request->global_seqno))
break;
active = request;
}
spin_unlock_irqrestore(&engine->timeline.lock, flags);
}
return active;
}
static void execlists_reset(struct intel_engine_cs *engine,