Commit 77e2faeb authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gt: Disable the ring before resetting HEAD/TAIL 



During the reset of ring submission, we first stop the engine by
clearing the HEAD/TAIL and marking the ring as disabled. However, it
would be safer to disable the ring (after emptying) before resetting the
HEAD/TAIL.

Suggested-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210119110802.22228-4-chris@chris-wilson.co.uk
parent 14139c3e

drivers/gpu/drm/i915/gt/intel_ring_submission.c

+7 −3
Original line number Diff line number Diff line
@@ -301,13 +301,17 @@ static void xcs_sanitize(struct intel_engine_cs *engine) 


static bool stop_ring(struct intel_engine_cs *engine)

{

	/* Empty the ring by skipping to the end */

	ENGINE_WRITE_FW(engine, RING_HEAD, ENGINE_READ_FW(engine, RING_TAIL));



	ENGINE_WRITE_FW(engine, RING_HEAD, 0);

	ENGINE_WRITE_FW(engine, RING_TAIL, 0);

	ENGINE_POSTING_READ(engine, RING_HEAD);



	/* The ring must be empty before it is disabled */

	ENGINE_WRITE_FW(engine, RING_CTL, 0);

	ENGINE_POSTING_READ(engine, RING_CTL);



	/* Then reset the disabled ring */

	ENGINE_WRITE_FW(engine, RING_HEAD, 0);

	ENGINE_WRITE_FW(engine, RING_TAIL, 0);



	return (ENGINE_READ_FW(engine, RING_HEAD) & HEAD_ADDR) == 0;

}