From 9bec9b1334d687c0a9fcf3d3a1987a61b4826a45 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 11 Aug 2014 09:21:35 +0100 Subject: [PATCH] drm/i915: Double check ring is idle before declaring the GPU wedged During ring initialisation, sometimes we observe, though not in production hardware, that the idle flag is not set even though the ring is empty. Double check before giving up. Signed-off-by: Chris Wilson Cc: Damien Lespiau Reviewed-by: Damien Lespiau Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_ringbuffer.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c index 117543e58d48..a059b64a0fb2 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -478,7 +478,12 @@ static bool stop_ring(struct intel_engine_cs *ring) I915_WRITE_MODE(ring, _MASKED_BIT_ENABLE(STOP_RING)); if (wait_for((I915_READ_MODE(ring) & MODE_IDLE) != 0, 1000)) { DRM_ERROR("%s : timed out trying to stop ring\n", ring->name); - return false; + /* Sometimes we observe that the idle flag is not + * set even though the ring is empty. So double + * check before giving up. + */ + if (I915_READ_HEAD(ring) != I915_READ_TAIL(ring)) + return false; } } -- 2.20.1