Re: [PATCH] drm/xe/debugfs: Expose per-engine idle status

["Purkait, Soham" <soham.purkait@intel.com>]

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Hi Airban,

On 10-06-2026 01:21, Sk Anirban wrote:
> Add a GT debugfs entry that iterates over engines and reports
> whether each engine is active or idle. This can help debug C6
> issues by identifying engines that may be preventing the GT
> from going idle.
>
> Signed-off-by: Sk Anirban<sk.anirban@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_gt_debugfs.c | 31 +++++++++++++++++++++++++++++-
>   1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_gt_debugfs.c b/drivers/gpu/drm/xe/xe_gt_debugfs.c
> index f45306308cd6..d404467146d1 100644
> --- a/drivers/gpu/drm/xe/xe_gt_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_gt_debugfs.c
> @@ -10,6 +10,8 @@
>   #include <drm/drm_debugfs.h>
>   #include <drm/drm_managed.h>
>   
> +#include "regs/xe_engine_regs.h"
> +
>   #include "xe_device.h"
>   #include "xe_force_wake.h"
>   #include "xe_gt.h" @@ -115,8 +117,10 @@ static int hw_engines(struct xe_gt *gt, struct 
> drm_printer *p) enum xe_hw_engine_id id; CLASS(xe_force_wake, 
> fw_ref)(gt_to_fw(gt), XE_FORCEWAKE_ALL); - if 
> (!xe_force_wake_ref_has_domain(fw_ref.domains, XE_FORCEWAKE_ALL)) + if 
> (!xe_force_wake_ref_has_domain(fw_ref.domains, XE_FORCEWAKE_ALL)) { + 
> drm_printf(p, "ERROR: Could not acquire forcewake\n");
>   		return -ETIMEDOUT;
> +	}
>   
>   	for_each_hw_engine(hwe, gt, id)
>   		xe_hw_engine_print(hwe, p);
> @@ -124,6 +128,30 @@ static int hw_engines(struct xe_gt *gt, struct drm_printer *p)
>   	return 0;
>   }
>   
> +static bool hw_engine_is_active(struct xe_hw_engine *hwe)
Should it be renamed as is_ring_empty or something similar ? Why the 
active ticks are nor being checked to evaluate the busyness ?
> +{
> +	u32 head = xe_hw_engine_mmio_read32(hwe, RING_HEAD(0));
> +	u32 tail = xe_hw_engine_mmio_read32(hwe, RING_TAIL(0));
> +
> +	return (head & HEAD_ADDR) != (tail & TAIL_ADDR);
> +}
> +
> +static int hw_engine_status(struct xe_gt *gt, struct drm_printer *p)
> +{
> +	struct xe_hw_engine *hwe;
> +	enum xe_hw_engine_id id;
> +
> +	CLASS(xe_force_wake, fw_ref)(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> +	if (!xe_force_wake_ref_has_domain(fw_ref.domains, XE_FORCEWAKE_ALL))

It silently returns -ETIMEDOUT on  failure. Better, a reason could be 
emitted as done for hw_engine().

Thanks, Soham

> +		return -ETIMEDOUT;
> +
> +	for_each_hw_engine(hwe, gt, id)
> +		drm_printf(p, "%s: %s\n", hwe->name,
> +			   hw_engine_is_active(hwe) ? "active" : "idle");
> +
> +	return 0;
> +}
> +
>   static int steering(struct xe_gt *gt, struct drm_printer *p)
>   {
>   	xe_gt_mcr_steering_dump(gt, p);
> @@ -240,6 +268,7 @@ static const struct drm_info_list vf_safe_debugfs_list[] = {
>   /* everything else should be added here */
>   static const struct drm_info_list pf_only_debugfs_list[] = {
>   	{ "hw_engines", .show = xe_gt_debugfs_show_with_rpm, .data = hw_engines },
> +	{ "hw_engine_status", .show = xe_gt_debugfs_show_with_rpm, .data = hw_engine_status },
>   	{ "mocs", .show = xe_gt_debugfs_show_with_rpm, .data = xe_mocs_dump },
>   	{ "pat", .show = xe_gt_debugfs_show_with_rpm, .data = xe_pat_dump },
>   	{ "powergate_info", .show = xe_gt_debugfs_show_with_rpm, .data = xe_gt_idle_pg_print },

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