diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_dma.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_dma.c | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index c628c3671394..91ef4c150193 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -79,6 +79,34 @@ int i915_wait_ring(struct drm_device * dev, int n, const char *caller) return -EBUSY; } +/* As a ringbuffer is only allowed to wrap between instructions, fill + * the tail with NOOPs. + */ +int i915_wrap_ring(struct drm_device *dev) +{ + drm_i915_private_t *dev_priv = dev->dev_private; + volatile unsigned int *virt; + int rem; + + rem = dev_priv->ring.Size - dev_priv->ring.tail; + if (dev_priv->ring.space < rem) { + int ret = i915_wait_ring(dev, rem, __func__); + if (ret) + return ret; + } + dev_priv->ring.space -= rem; + + virt = (unsigned int *) + (dev_priv->ring.virtual_start + dev_priv->ring.tail); + rem /= 4; + while (rem--) + *virt++ = MI_NOOP; + + dev_priv->ring.tail = 0; + + return 0; +} + /** * Sets up the hardware status page for devices that need a physical address * in the register. @@ -198,7 +226,6 @@ static int i915_initialize(struct drm_device * dev, drm_i915_init_t * init) } dev_priv->ring.Size = init->ring_size; - dev_priv->ring.tail_mask = dev_priv->ring.Size - 1; dev_priv->ring.map.offset = init->ring_start; dev_priv->ring.map.size = init->ring_size; |