[PATCH v4] drm/xe: Enlarge the invalidation timeout from 150 to 500

[Shuicheng Lin]

There are error messages like below that are occurring during stress testing:
"[   31.004009] xe 0000:03:00.0: [drm] ERROR GT0: Global invalidation timeout"
Previously it was hitting this 3 with 1000 executions of warm reboot.
After raising it to 500, 1000 warm reboot executions passed and it didn't
fail.

Due to the way xe_mmio_wait32() is implemented, the timeout is able to expire
early when the register matches the expected value due to the wait increments
starting small. So, the larger timeout value should have no effect during
normal use cases.

v2 (Jonathan):
  - rework the commit message
v3 (Lucas):
  - add conclusive message for the fail rate and test case
v4:
  - add suggested-by

Suggested-by: Jia Yao <jia.yao at intel.com>
Signed-off-by: Shuicheng Lin <shuicheng.lin at intel.com>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Cc: Matthew Auld <matthew.auld at intel.com>
Cc: Nirmoy Das <nirmoy.das at intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
Tested-by: Zongyao Bai <zongyao.bai at intel.com>
---
 drivers/gpu/drm/xe/xe_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 962751c966d1..22b572f0612c 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -925,7 +925,7 @@ void xe_device_l2_flush(struct xe_device *xe)
 	spin_lock(&gt->global_invl_lock);
 	xe_mmio_write32(&gt->mmio, XE2_GLOBAL_INVAL, 0x1);
 
-	if (xe_mmio_wait32(&gt->mmio, XE2_GLOBAL_INVAL, 0x1, 0x0, 150, NULL, true))
+	if (xe_mmio_wait32(&gt->mmio, XE2_GLOBAL_INVAL, 0x1, 0x0, 500, NULL, true))
 		xe_gt_err_once(gt, "Global invalidation timeout\n");
 	spin_unlock(&gt->global_invl_lock);
 
-- 
2.25.1