On 3/25/2022 11:37 AM, Das, Nirmoy wrote:
On 3/25/2022 6:58 PM, Daniele Ceraolo Spurio wrote:
In intel_gt_wait_for_idle, we use the remaining timeout returned from
intel_gt_retire_requests_timeout to wait on the GuC being idle. However,
the returned variable can have a negative value if something goes wrong
during the wait, leading to us hitting a GEM_BUG_ON in the GuC wait
function.
To fix this, make sure to only return the timeout if it is positive.
Fixes: b97060a99b01b ("drm/i915/guc: Update intel_gt_wait_for_idle to
work with GuC")
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
Cc: John Harrison <john.c.harrison@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_gt_requests.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
index edb881d756309..ef70c209976d8 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
@@ -197,7 +197,7 @@ out_active: spin_lock(&timelines->lock);
active_count++;
if (remaining_timeout)
- *remaining_timeout = timeout;
+ *remaining_timeout = timeout > 0 ? timeout : 0;
Should the last flush_submission() be "if ( timeout > 0
&&flush_submission(gt, timeout))" ?
I considered it, but flush_submission only checks for timeout != 0 so it
won't accidentally make use of a negative value thinking it's positive.
I don't know if the flush is purposely done even if timeout is negative
or if that's a mistake, but that code has been there long before we
modified the function to return the remaining timeout and never seems to
have caused issues, so I decided not to change it.
Daniele
Nirmoy
return active_count ? timeout : 0;
}
