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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2020-12-09 16:40:06 +0000 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2020-12-09 19:32:51 +0000 |
| commit | 63de1da1479968e256123097fe9d153183e5fe6c (patch) | |
| tree | 5efeff5706bbdfdf2f4b245f0a48475ce16dba31 | |
| parent | 338d58cf47a8820a8f0cd3b3b85e2dc304120f5b (diff) | |
| download | lwn-63de1da1479968e256123097fe9d153183e5fe6c.tar.gz lwn-63de1da1479968e256123097fe9d153183e5fe6c.zip | |
drm/i915: Remove livelock from "do_idle_maps" vtd w/a
A call to wait for the GT to idle from inside the put_pages fallback is
prone to cause an uninterruptible livelock. As it does not provide
adequate serialisation with new requests, simply fallback to a trivial
sleep.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201209164008.5487-1-chris@chris-wilson.co.uk
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_gtt.c | 25 |
1 files changed, 10 insertions, 15 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index c5ee1567f3d1..3ee2f682eff6 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -55,22 +55,17 @@ int i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj, void i915_gem_gtt_finish_pages(struct drm_i915_gem_object *obj, struct sg_table *pages) { - struct drm_i915_private *dev_priv = to_i915(obj->base.dev); - struct device *kdev = &dev_priv->drm.pdev->dev; - struct i915_ggtt *ggtt = &dev_priv->ggtt; - - if (unlikely(ggtt->do_idle_maps)) { - /* XXX This does not prevent more requests being submitted! */ - if (intel_gt_retire_requests_timeout(ggtt->vm.gt, - -MAX_SCHEDULE_TIMEOUT)) { - drm_err(&dev_priv->drm, - "Failed to wait for idle; VT'd may hang.\n"); - /* Wait a bit, in hopes it avoids the hang */ - udelay(10); - } - } + struct drm_i915_private *i915 = to_i915(obj->base.dev); + struct i915_ggtt *ggtt = &i915->ggtt; + + /* XXX This does not prevent more requests being submitted! */ + if (unlikely(ggtt->do_idle_maps)) + /* Wait a bit, in the hope it avoids the hang */ + usleep_range(100, 250); - dma_unmap_sg(kdev, pages->sgl, pages->nents, PCI_DMA_BIDIRECTIONAL); + dma_unmap_sg(&i915->drm.pdev->dev, + pages->sgl, pages->nents, + PCI_DMA_BIDIRECTIONAL); } /** |