From: Chris Wilson <chris@chris-wilson.co.uk>
To: intel-gfx@lists.freedesktop.org
Subject: [Intel-gfx] [CI 1/3] drm/i915: Remove livelock from "do_idle_maps" vtd w/a
Date: Wed, 9 Dec 2020 16:40:06 +0000 [thread overview]
Message-ID: <20201209164008.5487-1-chris@chris-wilson.co.uk> (raw)
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>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 25 ++++++++++---------------
1 file 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);
}
/**
--
2.20.1
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next reply other threads:[~2020-12-09 16:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 16:40 Chris Wilson [this message]
2020-12-09 16:40 ` [Intel-gfx] [CI 2/3] drm/i915: Sleep around performing iommu unmaps on Tigerlake Chris Wilson
2020-12-09 16:40 ` [Intel-gfx] [CI 3/3] drm/i915/gt: Remove uninterruptible parameter from intel_gt_wait_for_idle Chris Wilson
2020-12-09 17:49 ` [Intel-gfx] ✓ Fi.CI.BAT: success for series starting with [CI,1/3] drm/i915: Remove livelock from "do_idle_maps" vtd w/a Patchwork
2020-12-09 19:30 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201209164008.5487-1-chris@chris-wilson.co.uk \
--to=chris@chris-wilson.co.uk \
--cc=intel-gfx@lists.freedesktop.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.