[Intel-gfx] [PATCH 2/2] drm/i915/execlists: Record the active CCID from before reset

[Chris Wilson]

If we cannot trust the reset will flush out the CS event queue such that
process_csb() reports an accurate view of HW, we will need to search the
active and pending contexts to determine which was actually running at
the time we issued the reset.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gt/intel_engine_types.h | 5 +++++
 drivers/gpu/drm/i915/gt/intel_lrc.c          | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 80cdde712842..4804587442e7 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -166,6 +166,11 @@ struct intel_engine_execlists {
 	 */
 	u32 error_interrupt;
 
+	/**
+	 * @reset_ccid: Active CCID [EXECLISTS_STATUS_HI] at the time of reset
+	 */
+	u32 reset_ccid;
+
 	/**
 	 * @no_priolist: priority lists disabled
 	 */
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index f028114714cd..55bf3cdf3b38 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -3724,6 +3724,8 @@ static void execlists_reset_prepare(struct intel_engine_cs *engine)
 	 */
 	ring_set_paused(engine, 1);
 	intel_engine_stop_cs(engine);
+
+	engine->execlists.reset_ccid = active_ccid(engine);
 }
 
 static void reset_csb_pointers(struct intel_engine_cs *engine)
@@ -3798,7 +3800,7 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
 	 * its request, it was still running at the time of the
 	 * reset and will have been clobbered.
 	 */
-	rq = execlists_active(execlists);
+	rq = active_context(engine, engine->execlists.reset_ccid);
 	if (!rq)
 		goto unwind;
 
-- 
2.20.1