Module Name: src
Committed By: riastradh
Date: Wed Feb 25 13:35:25 UTC 2015
Modified Files:
src/sys/external/bsd/drm2/dist/drm/i915: intel_ringbuffer.c
Log Message:
Back-port attempt [2/2] to fix i915drmkms on G4X, from Linux.
commit 95468892fdfeef6d1004b524e35957629efdbe00
Author: Chris Wilson <[email protected]>
Date: Thu Aug 7 15:39:54 2014 +0100
drm/i915: Reset the HEAD pointer for the ring after writing START
Ville found an old w/a documented for g4x that suggested that we need to
reset the HEAD after writing START. This is a useful fixup for some of
the g4x ring initialisation woes, but as usual, not all.
v2: Do the rewrite unconditionally anyway
To generate a diff of this commit:
cvs rdiff -u -r1.5 -r1.6 \
src/sys/external/bsd/drm2/dist/drm/i915/intel_ringbuffer.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/external/bsd/drm2/dist/drm/i915/intel_ringbuffer.c
diff -u src/sys/external/bsd/drm2/dist/drm/i915/intel_ringbuffer.c:1.5 src/sys/external/bsd/drm2/dist/drm/i915/intel_ringbuffer.c:1.6
--- src/sys/external/bsd/drm2/dist/drm/i915/intel_ringbuffer.c:1.5 Wed Feb 25 13:30:02 2015
+++ src/sys/external/bsd/drm2/dist/drm/i915/intel_ringbuffer.c Wed Feb 25 13:35:25 2015
@@ -507,6 +507,14 @@ static int init_ring_common(struct intel
* also enforces ordering), otherwise the hw might lose the new ring
* register values. */
I915_WRITE_START(ring, i915_gem_obj_ggtt_offset(obj));
+
+ /* WaClearRingBufHeadRegAtInit:ctg,elk */
+ if (I915_READ_HEAD(ring))
+ DRM_DEBUG("%s initialization failed [head=%08x], fudging\n",
+ ring->name, I915_READ_HEAD(ring));
+ I915_WRITE_HEAD(ring, 0);
+ (void)I915_READ_HEAD(ring);
+
I915_WRITE_CTL(ring,
((ring->size - PAGE_SIZE) & RING_NR_PAGES)
| RING_VALID);
