drm/i915/ringbuffer: Ignore failure to setup the ring on Sandybridge

The ring buffer registers return 0 whilst idle (for some values of idle)
on early Sandybridge hw. Persevere even when all appears hopeless...
Fortunately the head auto-reporting prevents most hangs.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=31370
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Chris Wilson 2010-11-07 11:50:02 +00:00
parent ae69b42a10
commit 629e894173
1 changed files with 24 additions and 8 deletions
drivers/gpu/drm/i915

View File

@ -180,14 +180,30 @@ static int init_ring_common(struct intel_ring_buffer *ring)
if ((I915_READ_CTL(ring) & RING_VALID) == 0 || if ((I915_READ_CTL(ring) & RING_VALID) == 0 ||
I915_READ_START(ring) != obj_priv->gtt_offset || I915_READ_START(ring) != obj_priv->gtt_offset ||
(I915_READ_HEAD(ring) & HEAD_ADDR) != 0) { (I915_READ_HEAD(ring) & HEAD_ADDR) != 0) {
DRM_ERROR("%s initialization failed " if (IS_GEN6(ring->dev) && ring->dev->pdev->revision <= 8) {
"ctl %08x head %08x tail %08x start %08x\n", /* Early revisions of Sandybridge do not like
ring->name, * revealing the contents of the ring buffer
I915_READ_CTL(ring), * registers whilst idle. Fortunately, the
I915_READ_HEAD(ring), * auto-reporting mechanism prevents most hangs,
I915_READ_TAIL(ring), * but this will bite us eventually...
I915_READ_START(ring)); */
return -EIO; DRM_DEBUG("%s initialization failed "
"ctl %08x head %08x tail %08x start %08x. Ignoring, hope for the best!\n",
ring->name,
I915_READ_CTL(ring),
I915_READ_HEAD(ring),
I915_READ_TAIL(ring),
I915_READ_START(ring));
} else {
DRM_ERROR("%s initialization failed "
"ctl %08x head %08x tail %08x start %08x\n",
ring->name,
I915_READ_CTL(ring),
I915_READ_HEAD(ring),
I915_READ_TAIL(ring),
I915_READ_START(ring));
return -EIO;
}
} }
if (!drm_core_check_feature(ring->dev, DRIVER_MODESET)) if (!drm_core_check_feature(ring->dev, DRIVER_MODESET))