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

[Cavitt, Jonathan]

-----Original Message-----
From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of Shuicheng Lin
Sent: Wednesday, October 9, 2024 10:22 AM
To: intel-xe at lists.freedesktop.org; Auld, Matthew <matthew.auld at intel.com>; Das, Nirmoy <nirmoy.das at intel.com>
Cc: Lin, Shuicheng <shuicheng.lin at intel.com>
Subject: [PATCH] drm/xe: Enlarge the invalidation timeout from 150 to 500
> 
> There is error message like below during stress test.
> "[   31.004009] xe 0000:03:00.0: [drm] ERROR GT0: Global invalidation timeout"
> And change the timeout value from 150 to 500, could help avoid
> this error message in the stress test.
> xe_mmio_wait32() is implemented as wait 10us at beginning, then
> double the wait value as next wait until the timeout value is
> reached. So for the normal case, the real wait time is not changed.
> The larger timeout value should take effect for the bad case only.
> 
> Signed-off-by: Shuicheng Lin <shuicheng.lin at intel.com>

This looks good, though maybe the commit message could use some work.
Something like:

"""
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"
Changing the timeout value from 150 to 500 could help avoid these error
messages in the stress tests.

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.
"""

Reviewed-by: Jonathan Cavitt <jonathan.cavitt at intel.com>
-Jonathan Cavitt

> ---
>  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 cd241a8e1838..60aebf7561ec 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
> 
>