Skip to content

Commit

Permalink
drm/i915: Squelch any ktime/jiffie rounding errors for wait-ioctl
Browse files Browse the repository at this point in the history
We wait upon jiffies, but report the time elapsed using a
high-resolution timer. This discrepancy can lead to us timing out the
wait prior to us reporting the elapsed time as complete.

This restores the squelching lost in commit e95433c ("drm/i915:
Rearrange i915_wait_request() accounting with callers").

Fixes: e95433c ("drm/i915: Rearrange i915_wait_request() accounting with callers")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.10-rc1+
Cc: stable@vger.kernel.org
Link: http://patchwork.freedesktop.org/patch/msgid/20170216125441.30923-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
(cherry picked from commit c1d2061)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
  • Loading branch information
Chris Wilson authored and Jani Nikula committed Mar 9, 2017
1 parent 70647f9 commit 89cf83d
Showing 1 changed file with 10 additions and 0 deletions.
10 changes: 10 additions & 0 deletions drivers/gpu/drm/i915/i915_gem.c
Original file line number Diff line number Diff line change
Expand Up @@ -3029,6 +3029,16 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
args->timeout_ns -= ktime_to_ns(ktime_sub(ktime_get(), start));
if (args->timeout_ns < 0)
args->timeout_ns = 0;

/*
* Apparently ktime isn't accurate enough and occasionally has a
* bit of mismatch in the jiffies<->nsecs<->ktime loop. So patch
* things up to make the test happy. We allow up to 1 jiffy.
*
* This is a regression from the timespec->ktime conversion.
*/
if (ret == -ETIME && !nsecs_to_jiffies(args->timeout_ns))
args->timeout_ns = 0;
}

i915_gem_object_put(obj);
Expand Down

0 comments on commit 89cf83d

Please sign in to comment.