[PATCH v3] drm/xe/ufence: Flush xe ordered_wq in case of ufence timeout

[Nirmoy Das <nirmoy.das@intel.com>]

Flush xe ordered_wq in case of ufence timeout which is observed
on LNL and that points to recent scheduling issue with E-cores.

This is similar to the recent fix:
commit e51527233804 ("drm/xe/guc/ct: Flush g2h worker in case of g2h
response timeout") and should be removed once there is a E-core
scheduling fix for LNL.

v2: Add platform check(Himal)
    s/__flush_workqueue/flush_workqueue(Jani)
v3: Remove gfx platform check as the issue related to cpu
    platform(John)

Cc: Badal Nilawar <badal.nilawar@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: <stable@vger.kernel.org> # v6.11+
Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2754
Suggested-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_wait_user_fence.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_wait_user_fence.c b/drivers/gpu/drm/xe/xe_wait_user_fence.c
index f5deb81eba01..886c9862d89c 100644
--- a/drivers/gpu/drm/xe/xe_wait_user_fence.c
+++ b/drivers/gpu/drm/xe/xe_wait_user_fence.c
@@ -155,6 +155,17 @@ int xe_wait_user_fence_ioctl(struct drm_device *dev, void *data,
 		}
 
 		if (!timeout) {
+			/*
+			 * This is analogous to e51527233804 ("drm/xe/guc/ct: Flush g2h worker
+			 * in case of g2h response timeout")
+			 *
+			 * TODO: Drop this change once workqueue scheduling delay issue is
+			 * fixed on LNL Hybrid CPU.
+			 */
+			flush_workqueue(xe->ordered_wq);
+			err = do_compare(addr, args->value, args->mask, args->op);
+			if (err <= 0)
+				break;
 			err = -ETIME;
 			break;
 		}
-- 
2.46.0