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<b><a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO --- - [gm45 regression] [drm:init_ring_common]: *ERROR* render ring initialization failed"
href="https://bugs.freedesktop.org/show_bug.cgi?id=76554#c44">Comment # 44</a>
on <a class="bz_bug_link
bz_status_NEEDINFO "
title="NEEDINFO --- - [gm45 regression] [drm:init_ring_common]: *ERROR* render ring initialization failed"
href="https://bugs.freedesktop.org/show_bug.cgi?id=76554">bug 76554</a>
from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
<pre>diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c
b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 5a74986348c6..b46b3e928a7f 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -530,6 +530,17 @@ static int init_ring_common(struct intel_ring_buffer
*ring)
((ring->size - PAGE_SIZE) & RING_NR_PAGES)
| RING_VALID);
+ if (I915_READ_START(ring) != i915_gem_obj_ggtt_offset(obj)) {
+ printk(KERN_ERR
+ "%s initialization failed"
+ " [%08x != %08x], fudging\n",
+ ring->name,
+ I915_READ_START(ring),
+ i915_gem_obj_ggtt_offset(obj));
+ I915_WRITE_START(ring, i915_gem_obj_ggtt_offset(obj));
+ POSTING_READ(ring);
+ }
+
iowrite32(MI_NOOP, ring->virtual_start + 0);
iowrite32(MI_NOOP, ring->virtual_start + 4);
ring->write_tail(ring, 8);</pre>
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