Re: [PATCH v8 10/26] drm/xe/xe_gt_idle: Update handling of xe_force_wake_get return

["Nilawar, Badal" <badal.nilawar@intel.com>]

On 08-10-2024 12:40, Himal Prasad Ghimiray wrote:
> xe_force_wake_get() now returns the reference count-incremented domain
> mask. If it fails for individual domains, the return value will always
> be 0. However, for XE_FORCEWAKE_ALL, it may return a non-zero value even
> in the event of failure. Update the return handling of xe_force_wake_get()
> to reflect this behavior, and ensure that the return value is passed as
> input to xe_force_wake_put().
> 
> v3
> - return xe_wakeref_t instead of int in xe_force_wake_get()
> - xe_force_wake_put() error doesn't need to be checked. It internally
> WARNS on domain ack failure.
> 
> v4
> - Rebase fix
> 
> v5
> - return unsigned int for xe_force_wake_get()
> - Remove reudandant WARN calls.
> 
> v7
> - Fix commit message
> 
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_gt_idle.c | 26 +++++++++++++++-----------
>   1 file changed, 15 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_idle.c b/drivers/gpu/drm/xe/xe_gt_idle.c
> index 746812aee8ff..fd80afeef56a 100644
> --- a/drivers/gpu/drm/xe/xe_gt_idle.c
> +++ b/drivers/gpu/drm/xe/xe_gt_idle.c
> @@ -101,6 +101,7 @@ void xe_gt_idle_enable_pg(struct xe_gt *gt)
>   	struct xe_gt_idle *gtidle = &gt->gtidle;
>   	struct xe_mmio *mmio = &gt->mmio;
>   	u32 vcs_mask, vecs_mask;
> +	unsigned int fw_ref;
>   	int i, j;
>   
>   	if (IS_SRIOV_VF(xe))
> @@ -127,7 +128,7 @@ void xe_gt_idle_enable_pg(struct xe_gt *gt)
>   						     VDN_MFXVDENC_POWERGATE_ENABLE(j));
>   	}
>   
> -	XE_WARN_ON(xe_force_wake_get(gt_to_fw(gt), XE_FW_GT));
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
>   	if (xe->info.skip_guc_pc) {
>   		/*
>   		 * GuC sets the hysteresis value when GuC PC is enabled
> @@ -138,12 +139,13 @@ void xe_gt_idle_enable_pg(struct xe_gt *gt)
>   	}
>   
>   	xe_mmio_write32(mmio, POWERGATE_ENABLE, gtidle->powergate_enable);
> -	XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FW_GT));
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   }
>   
>   void xe_gt_idle_disable_pg(struct xe_gt *gt)
>   {
>   	struct xe_gt_idle *gtidle = &gt->gtidle;
> +	unsigned int fw_ref;
>   
>   	if (IS_SRIOV_VF(gt_to_xe(gt)))
>   		return;
> @@ -151,9 +153,9 @@ void xe_gt_idle_disable_pg(struct xe_gt *gt)
>   	xe_device_assert_mem_access(gt_to_xe(gt));
>   	gtidle->powergate_enable = 0;
>   
> -	XE_WARN_ON(xe_force_wake_get(gt_to_fw(gt), XE_FW_GT));
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
>   	xe_mmio_write32(&gt->mmio, POWERGATE_ENABLE, gtidle->powergate_enable);
> -	XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FW_GT));
> +	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   }
>   
>   /**
> @@ -172,7 +174,8 @@ int xe_gt_idle_pg_print(struct xe_gt *gt, struct drm_printer *p)
>   	enum xe_gt_idle_state state;
>   	u32 pg_enabled, pg_status = 0;
>   	u32 vcs_mask, vecs_mask;
> -	int err, n;
> +	unsigned int fw_ref;
> +	int n;
>   	/*
>   	 * Media Slices
>   	 *
> @@ -208,14 +211,14 @@ int xe_gt_idle_pg_print(struct xe_gt *gt, struct drm_printer *p)
>   
>   	/* Do not wake the GT to read powergating status */
>   	if (state != GT_IDLE_C6) {
> -		err = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
> -		if (err)
> -			return err;
> +		fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
> +		if (!fw_ref)
> +			return -ETIMEDOUT;
>   
>   		pg_enabled = xe_mmio_read32(&gt->mmio, POWERGATE_ENABLE);
>   		pg_status = xe_mmio_read32(&gt->mmio, POWERGATE_DOMAIN_STATUS);
>   
> -		XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FW_GT));
> +		xe_force_wake_put(gt_to_fw(gt), fw_ref);
>   	}
>   
>   	if (gt->info.engine_mask & XE_HW_ENGINE_RCS_MASK) {
> @@ -298,13 +301,14 @@ static void gt_idle_fini(void *arg)
>   {
>   	struct kobject *kobj = arg;
>   	struct xe_gt *gt = kobj_to_gt(kobj->parent);
> +	unsigned int fw_ref;
>   
>   	xe_gt_idle_disable_pg(gt);
>   
>   	if (gt_to_xe(gt)->info.skip_guc_pc) {
> -		XE_WARN_ON(xe_force_wake_get(gt_to_fw(gt), XE_FW_GT));
> +		fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
>   		xe_gt_idle_disable_c6(gt);
> -		xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
> +		xe_force_wake_put(gt_to_fw(gt), fw_ref);

LGTM
Reviewed-by: Badal Nilawar <badal.nilawar@intel.com>

Regards,
Badal

>   	}
>   
>   	sysfs_remove_files(kobj, gt_idle_attrs);