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

[Nirmoy Das]

On 10/15/2024 6:12 PM, Shuicheng Lin wrote:
> 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>
Reviewed-by: Nirmoy Das <nirmoy.das 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);
>