On Fri, Mar 16, 2012 at 12:43:22PM -0400, Sean Paul wrote:
> I have seen a number of "blt ring initialization failed" messages
> where the ctl or start registers are not the correct value. Upon further
> inspection, if the code just waited a little bit, it would read the
> correct value. Adding the wait_for to these reads should eliminate the
> issue.
>
> Signed-off-by: Sean Paul <seanpaul at chromium.org>
Reviewed-by: Ben Widawsky <ben at bwidawsk.net>
> ---
> drivers/gpu/drm/i915/intel_ringbuffer.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 8357822..d95f0f9 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -298,9 +298,9 @@ static int init_ring_common(struct intel_ring_buffer *ring)
> | RING_REPORT_64K | RING_VALID);
>
> /* If the head is still not zero, the ring is dead */
> - if ((I915_READ_CTL(ring) & RING_VALID) == 0 ||
> - I915_READ_START(ring) != obj->gtt_offset ||
> - (I915_READ_HEAD(ring) & HEAD_ADDR) != 0) {
> + if (wait_for((I915_READ_CTL(ring) & RING_VALID) != 0 &&
> + I915_READ_START(ring) == obj->gtt_offset &&
> + (I915_READ_HEAD(ring) & HEAD_ADDR) == 0, 50)) {
> DRM_ERROR("%s initialization failed "
> "ctl %08x head %08x tail %08x start %08x\n",
> ring->name,
> --
> 1.7.7.3
>
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