Re: [PATCH 2/2] drm/xe: Ensure GT is in C0 during resumes

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Aug 22, 2025 at 12:53:40PM -0700, Xin Wang wrote:
> This patch ensures the gt will be awake for the entire duration
> of the resume sequences until GuCRC takes over and GT-C6 gets
> re-enabled.

Differently of the previous patch this tells what, but doesn't tell why.
Perhaps we should add:

Before suspending GT-C6 is kept enabled, but upon resume, GuCRC
is not yet alive to properly control the exits and some cases of
instability and corruption related to GT-C6 can be observed.

Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4037

> Suggested-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: Xin Wang <x.wang@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_pm.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
> index 51934d5dc44f..a2e85030b7f4 100644
> --- a/drivers/gpu/drm/xe/xe_pm.c
> +++ b/drivers/gpu/drm/xe/xe_pm.c
> @@ -18,7 +18,7 @@
>  #include "xe_device.h"
>  #include "xe_ggtt.h"
>  #include "xe_gt.h"
> -#include "xe_guc.h"
> +#include "xe_gt_idle.h"
>  #include "xe_i2c.h"
>  #include "xe_irq.h"
>  #include "xe_pcode.h"
> @@ -177,6 +177,9 @@ int xe_pm_resume(struct xe_device *xe)
>  	drm_dbg(&xe->drm, "Resuming device\n");
>  	trace_xe_pm_resume(xe, __builtin_return_address(0));
>  
> +	for_each_gt(gt, xe, id)
> +		xe_gt_idle_disable_c6(gt);
> +
>  	for_each_tile(tile, xe, id)
>  		xe_wa_apply_tile_workarounds(tile);
>  
> @@ -533,6 +536,9 @@ int xe_pm_runtime_resume(struct xe_device *xe)
>  
>  	xe_rpm_lockmap_acquire(xe);
>  
> +	for_each_gt(gt, xe, id)
> +		xe_gt_idle_disable_c6(gt);
> +
>  	if (xe->d3cold.allowed) {
>  		err = xe_pcode_ready(xe, true);
>  		if (err)
> -- 
> 2.43.0
>