From: Chris Wilson Date: Tue, 19 Jan 2021 11:08:00 +0000 (+0000) Subject: drm/i915/gt: Disable the ring before resetting HEAD/TAIL X-Git-Tag: v5.15~1634^2~16^2~22 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=77e2faeb0744515939c4f5651e0d39ead96b39f1;p=platform%2Fkernel%2Flinux-starfive.git 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: Mika Kuoppala Signed-off-by: Chris Wilson Cc: Mika Kuoppala Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20210119110802.22228-4-chris@chris-wilson.co.uk --- diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c index 4415959..8a5314b 100644 --- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c @@ -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; }