From 50aa253d820ad4577e2231202f2c8fd89f9dc4e6 Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Tue, 14 Oct 2008 17:20:35 -0700 Subject: i915: Fix up ring initialization to cover G45 oddities G45 appears quite sensitive to ring initialization register writes, sometimes leaving the HEAD register with the START register contents. Check to make sure HEAD is reset correctly when START is written, and fix it up, screaming loudly. Signed-off-by: Keith Packard Signed-off-by: Eric Anholt Signed-off-by: Dave Airlie --- drivers/gpu/drm/i915/i915_gem.c | 37 +++++++++++++++++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-) (limited to 'drivers/gpu') diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index a31ee3202f1..94b9bdce0c7 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2350,6 +2350,7 @@ i915_gem_init_ringbuffer(struct drm_device *dev) struct drm_gem_object *obj; struct drm_i915_gem_object *obj_priv; int ret; + u32 head; ret = i915_gem_init_hws(dev); if (ret != 0) @@ -2390,17 +2391,49 @@ i915_gem_init_ringbuffer(struct drm_device *dev) /* Stop the ring if it's running. */ I915_WRITE(PRB0_CTL, 0); - I915_WRITE(PRB0_HEAD, 0); I915_WRITE(PRB0_TAIL, 0); - I915_WRITE(PRB0_START, 0); + I915_WRITE(PRB0_HEAD, 0); /* Initialize the ring. */ I915_WRITE(PRB0_START, obj_priv->gtt_offset); + head = I915_READ(PRB0_HEAD) & HEAD_ADDR; + + /* G45 ring initialization fails to reset head to zero */ + if (head != 0) { + DRM_ERROR("Ring head not reset to zero " + "ctl %08x head %08x tail %08x start %08x\n", + I915_READ(PRB0_CTL), + I915_READ(PRB0_HEAD), + I915_READ(PRB0_TAIL), + I915_READ(PRB0_START)); + I915_WRITE(PRB0_HEAD, 0); + + DRM_ERROR("Ring head forced to zero " + "ctl %08x head %08x tail %08x start %08x\n", + I915_READ(PRB0_CTL), + I915_READ(PRB0_HEAD), + I915_READ(PRB0_TAIL), + I915_READ(PRB0_START)); + } + I915_WRITE(PRB0_CTL, ((obj->size - 4096) & RING_NR_PAGES) | RING_NO_REPORT | RING_VALID); + head = I915_READ(PRB0_HEAD) & HEAD_ADDR; + + /* If the head is still not zero, the ring is dead */ + if (head != 0) { + DRM_ERROR("Ring initialization failed " + "ctl %08x head %08x tail %08x start %08x\n", + I915_READ(PRB0_CTL), + I915_READ(PRB0_HEAD), + I915_READ(PRB0_TAIL), + I915_READ(PRB0_START)); + return -EIO; + } + /* Update our cache of the ring state */ i915_kernel_lost_context(dev); -- cgit v1.2.3