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Commit 63572937 authored by Chris Wilson's avatar Chris Wilson
Browse files

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: default avatarChris 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: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180516183355.10553-7-chris@chris-wilson.co.uk
parent 73377dbc

drivers/gpu/drm/i915/intel_lrc.c

+35 −1
Original line number Diff line number Diff line
@@ -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,