Re: [PATCH 02/33] drm/xe/eustall: Store forcewake reference in stream structure

[Harish Chegondi <harish.chegondi@intel.com>]

On Fri, Nov 07, 2025 at 10:13:18AM -0800, Matt Roper wrote:
> Calls to xe_force_wake_put() should generally pass the exact reference
> returned by xe_force_wake_get().  Since EU stall grabs and releases
> forcewake in different functions, xe_eu_stall_disable_locked() is
> currently calling put with a hardcoded RENDER domain.  Although this
> works for now, it's somewhat fragile in case the power domain(s)
> required by stall sampling change in the future, or if workarounds show
> up that require us to obtain additional domains.
> 
> Stash the original reference obtained during stream enable inside the
> stream structure so that we can use it directly when the stream is
> disabled.
> 
> Cc: Harish Chegondi <harish.chegondi@intel.com>
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Harish Chegondi <harish.chegondi@intel.com>

Thanks for the patch
Harish.

> ---
>  drivers/gpu/drm/xe/xe_eu_stall.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_eu_stall.c b/drivers/gpu/drm/xe/xe_eu_stall.c
> index 650e45f6a7c7..97dfb7945b7a 100644
> --- a/drivers/gpu/drm/xe/xe_eu_stall.c
> +++ b/drivers/gpu/drm/xe/xe_eu_stall.c
> @@ -49,6 +49,7 @@ struct xe_eu_stall_data_stream {
>  	wait_queue_head_t poll_wq;
>  	size_t data_record_size;
>  	size_t per_xecore_buf_size;
> +	unsigned int fw_ref;
>  
>  	struct xe_gt *gt;
>  	struct xe_bo *bo;
> @@ -660,13 +661,12 @@ static int xe_eu_stall_stream_enable(struct xe_eu_stall_data_stream *stream)
>  	struct per_xecore_buf *xecore_buf;
>  	struct xe_gt *gt = stream->gt;
>  	u16 group, instance;
> -	unsigned int fw_ref;
>  	int xecore;
>  
>  	/* Take runtime pm ref and forcewake to disable RC6 */
>  	xe_pm_runtime_get(gt_to_xe(gt));
> -	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_RENDER);
> -	if (!xe_force_wake_ref_has_domain(fw_ref, XE_FW_RENDER)) {
> +	stream->fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_RENDER);
> +	if (!xe_force_wake_ref_has_domain(stream->fw_ref, XE_FW_RENDER)) {
>  		xe_gt_err(gt, "Failed to get RENDER forcewake\n");
>  		xe_pm_runtime_put(gt_to_xe(gt));
>  		return -ETIMEDOUT;
> @@ -832,7 +832,7 @@ static int xe_eu_stall_disable_locked(struct xe_eu_stall_data_stream *stream)
>  		xe_gt_mcr_multicast_write(gt, ROW_CHICKEN2,
>  					  _MASKED_BIT_DISABLE(DISABLE_DOP_GATING));
>  
> -	xe_force_wake_put(gt_to_fw(gt), XE_FW_RENDER);
> +	xe_force_wake_put(gt_to_fw(gt), stream->fw_ref);
>  	xe_pm_runtime_put(gt_to_xe(gt));
>  
>  	return 0;
> -- 
> 2.51.1
>