From aed2fc102ffaa9bd41e4cff140d3ec8482d13ff5 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 30 May 2017 13:13:34 +0100 Subject: [PATCH] drm/i915: Check the ring is empty when declaring the engines are idle As another precaution when testing whether the CS engine is actually idle, also inspect the ring's HEAD/TAIL registers, which should be equal when there are no commands left to execute by the GPU. Signed-off-by: Chris Wilson Cc: Mika Kuoppala Link: http://patchwork.freedesktop.org/patch/msgid/20170530121334.17364-3-chris@chris-wilson.co.uk Reviewed-by: Mika Kuoppala --- drivers/gpu/drm/i915/intel_engine_cs.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index 699f2d3861c7..bc38bd128b76 100644 --- a/drivers/gpu/drm/i915/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/intel_engine_cs.c @@ -1212,6 +1212,11 @@ static bool ring_is_idle(struct intel_engine_cs *engine) intel_runtime_pm_get(dev_priv); + /* First check that no commands are left in the ring */ + if ((I915_READ_HEAD(engine) & HEAD_ADDR) != + (I915_READ_TAIL(engine) & TAIL_ADDR)) + idle = false; + /* No bit for gen2, so assume the CS parser is idle */ if (INTEL_GEN(dev_priv) > 2 && !(I915_READ_MODE(engine) & MODE_IDLE)) idle = false; -- 2.20.1