From 0ef82af7253c1929a3995f271b8b0db462d1a0c3 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sat, 5 Sep 2009 18:07:06 +0100 Subject: drm/i915: Pad ringbuffer with NOOPs before wrapping MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit According to the docs, the ringbuffer is not allowed to wrap in the middle of an instruction. G45 PRM, Vol 1b, p101: While the “free space” wrap may allow commands to be wrapped around the end of the Ring Buffer, the wrap should only occur between commands. Padding (with NOP) may be required to follow this restriction. Do as commanded. [Having seen bug reports where there is evidence of split commands, but apparently the GPU has continued on merrily before a bizarre and untimely death, this may or may not fix a few random hangs.] Signed-off-by: Chris Wilson CC: Eric Anholt Signed-off-by: Eric Anholt --- drivers/gpu/drm/i915/i915_debugfs.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'drivers/gpu/drm/i915/i915_debugfs.c') diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 8f28325bc5ef..1e3bdcee863c 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -333,15 +333,13 @@ static int i915_ringbuffer_info(struct seq_file *m, void *data) struct drm_info_node *node = (struct drm_info_node *) m->private; struct drm_device *dev = node->minor->dev; drm_i915_private_t *dev_priv = dev->dev_private; - unsigned int head, tail, mask; + unsigned int head, tail; head = I915_READ(PRB0_HEAD) & HEAD_ADDR; tail = I915_READ(PRB0_TAIL) & TAIL_ADDR; - mask = dev_priv->ring.tail_mask; seq_printf(m, "RingHead : %08x\n", head); seq_printf(m, "RingTail : %08x\n", tail); - seq_printf(m, "RingMask : %08x\n", mask); seq_printf(m, "RingSize : %08lx\n", dev_priv->ring.Size); seq_printf(m, "Acthd : %08x\n", I915_READ(IS_I965G(dev) ? ACTHD_I965 : ACTHD)); -- cgit v1.2.3