drm/i915: Protect active fences on i915

The i915 also uses the fence registers for GPU access to tiled buffers so
we cannot reallocate one whilst it is on the active list. By performing a
LRU scan of the fenced buffers we also avoid waiting the possibility of
waiting on a pinned, or otherwise unusable, buffer.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
This commit is contained in:
Chris Wilson 2009-02-11 14:26:47 +00:00 committed by Eric Anholt
parent fc7170ba28
commit d7619c4b9c

View file

@ -1595,18 +1595,32 @@ try_again:
/* None available, try to steal one or wait for a user to finish */
if (i == dev_priv->num_fence_regs) {
uint32_t seqno = dev_priv->mm.next_gem_seqno;
loff_t offset;
if (avail == 0)
return -ENOMEM;
/* Could try to use LRU here instead... */
for (i = dev_priv->fence_reg_start;
i < dev_priv->num_fence_regs; i++) {
uint32_t this_seqno;
reg = &dev_priv->fence_regs[i];
old_obj_priv = reg->obj->driver_private;
if (!old_obj_priv->pin_count)
if (old_obj_priv->pin_count)
continue;
/* i915 uses fences for GPU access to tiled buffers */
if (IS_I965G(dev) || !old_obj_priv->active)
break;
/* find the seqno of the first available fence */
this_seqno = old_obj_priv->last_rendering_seqno;
if (this_seqno != 0 &&
reg->obj->write_domain == 0 &&
i915_seqno_passed(seqno, this_seqno))
seqno = this_seqno;
}
/*
@ -1614,15 +1628,25 @@ try_again:
* objects to finish before trying again.
*/
if (i == dev_priv->num_fence_regs) {
ret = i915_gem_object_set_to_gtt_domain(reg->obj, 0);
if (ret) {
WARN(ret != -ERESTARTSYS,
"switch to GTT domain failed: %d\n", ret);
return ret;
if (seqno == dev_priv->mm.next_gem_seqno) {
i915_gem_flush(dev,
I915_GEM_GPU_DOMAINS,
I915_GEM_GPU_DOMAINS);
seqno = i915_add_request(dev,
I915_GEM_GPU_DOMAINS);
if (seqno == 0)
return -ENOMEM;
}
ret = i915_wait_request(dev, seqno);
if (ret)
return ret;
goto try_again;
}
BUG_ON(old_obj_priv->active ||
(reg->obj->write_domain & I915_GEM_GPU_DOMAINS));
/*
* Zap this virtual mapping so we can set up a fence again
* for this object next time we need it.