[PATCH v2] drm/xe/ufence: Flush xe ordered_wq in case of ufence timeout

[Nirmoy Das]

Flush xe ordered_wq in case of ufence timeout which is observed
on LNL and that points to the 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 E core
scheduling fix.

v2: Add platform check(Himal)
    s/__flush_workqueue/flush_workqueue(Jani)

Cc: Badal Nilawar <badal.nilawar at intel.com>
Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Matthew Auld <matthew.auld at intel.com>
Cc: John Harrison <John.C.Harrison at Intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Cc: <stable at vger.kernel.org> # v6.11+
Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2754
Suggested-by: Matthew Brost <matthew.brost at intel.com>
Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
Reviewed-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/xe_wait_user_fence.c | 14 ++++++++++++++
 1 file changed, 14 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..78a0ad3c78fe 100644
--- a/drivers/gpu/drm/xe/xe_wait_user_fence.c
+++ b/drivers/gpu/drm/xe/xe_wait_user_fence.c
@@ -13,6 +13,7 @@
 #include "xe_device.h"
 #include "xe_gt.h"
 #include "xe_macros.h"
+#include "compat-i915-headers/i915_drv.h"
 #include "xe_exec_queue.h"
 
 static int do_compare(u64 addr, u64 value, u64 mask, u16 op)
@@ -155,6 +156,19 @@ int xe_wait_user_fence_ioctl(struct drm_device *dev, void *data,
 		}
 
 		if (!timeout) {
+			if (IS_LUNARLAKE(xe)) {
+				/*
+				 * 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