Re: [PATCH v3] drm/xe: improve readability of debugfs info engine output

[Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>]

On Mon, Mar 30, 2026 at 05:29:44PM -0700, Xin Wang wrote:
>Improve the readability of the info debugfs output by replacing
>raw numeric engine masks with human-readable engine and class
>names.
>
>Also expose multi_lrc_engine_classes in the info output and print
>per-GT engine capability data in a form that is easier to inspect
>manually and simpler for userspace tests to consume.
>
>This avoids requiring userspace to duplicate kernel mask decoding
>logic when validating engine capabilities.
>
>Signed-off-by: Xin Wang <x.wang@intel.com>
>---
> drivers/gpu/drm/xe/xe_debugfs.c | 44 ++++++++++++++++++++++++++++++---
> 1 file changed, 40 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
>index 844cfafe1ec7..9d1c388054e4 100644
>--- a/drivers/gpu/drm/xe/xe_debugfs.c
>+++ b/drivers/gpu/drm/xe/xe_debugfs.c
>@@ -15,9 +15,11 @@
> #include "xe_bo.h"
> #include "xe_device.h"
> #include "xe_force_wake.h"
>+#include "xe_gt.h"
> #include "xe_gt_debugfs.h"
> #include "xe_gt_printk.h"
> #include "xe_guc_ads.h"
>+#include "xe_hw_engine.h"
> #include "xe_mmio.h"
> #include "xe_pm.h"
> #include "xe_psmi.h"
>@@ -61,6 +63,37 @@ static struct xe_device *node_to_xe(struct drm_info_node *node)
> 	return to_xe_device(node->minor->dev);
> }
>
>+static void print_engine_class_mask(struct drm_printer *p, const char *label, u8 mask)
>+{
>+	drm_printf(p, "%s", label);
>+	if (mask) {
>+		for (enum xe_engine_class ec = 0; ec < XE_ENGINE_CLASS_MAX; ec++) {

If there is one usecase, there will probably many that follow :)
Can make make this a macro 'for_each_hw_engine_class()'?

>+			if (mask & BIT(ec))
>+				drm_printf(p, " %s", xe_hw_engine_class_to_str(ec));
>+		}
>+	} else {
>+		drm_printf(p, " none");
>+	}
>+	drm_printf(p, "\n");
>+}
>+
>+static void print_engine_mask(struct drm_printer *p, const char *label,
>+			      struct xe_gt *gt, u64 mask)
>+{
>+	struct xe_hw_engine *hwe;
>+	enum xe_hw_engine_id id;
>+
>+	drm_printf(p, "%s", label);
>+	if (mask) {
>+		for_each_hw_engine(hwe, gt, id)
>+			if (mask & BIT_ULL(id))
>+				drm_printf(p, " %s", hwe->name);
>+	} else {
>+		drm_printf(p, " none");
>+	}
>+	drm_printf(p, "\n");
>+}
>+
> static int info(struct seq_file *m, void *data)
> {
> 	struct xe_device *xe = node_to_xe(m->private);
>@@ -88,13 +121,16 @@ static int info(struct seq_file *m, void *data)
> 	drm_printf(&p, "has_flat_ccs %s\n", str_yes_no(xe->info.has_flat_ccs));
> 	drm_printf(&p, "has_usm %s\n", str_yes_no(xe->info.has_usm));
> 	drm_printf(&p, "skip_guc_pc %s\n", str_yes_no(xe->info.skip_guc_pc));
>+	print_engine_class_mask(&p, "multi_lrc_engine_classes", xe->info.multi_lrc_mask);

May be add this as a separate patch.

> 	for_each_gt(gt, xe, id) {
>+		char label[40];
>+
> 		drm_printf(&p, "gt%d force wake %d\n", id,
> 			   xe_force_wake_ref(gt_to_fw(gt), XE_FW_GT));
>-		drm_printf(&p, "gt%d engine_mask 0x%llx\n", id,
>-			   gt->info.engine_mask);
>-		drm_printf(&p, "gt%d multi_queue_engine_class_mask 0x%x\n", id,
>-			   gt->info.multi_queue_engine_class_mask);
>+		snprintf(label, sizeof(label), "gt%d engines", id);
>+		print_engine_mask(&p, label, gt, gt->info.engine_mask);
>+		snprintf(label, sizeof(label), "gt%d multi_queue_engine_classes", id);
>+		print_engine_class_mask(&p, label, gt->info.multi_queue_engine_class_mask);

Do we need to pass the label? We can probably just print that here? I am fine with passing also.

I am bit concerned about it breaking the ABI. I did not see IGT code relying on these masks,
but it is better to check with maintainers also.

Other than these, patch looks good to me.
Reviewed-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>

Niranjana

> 	}
>
> 	return 0;
>-- 
>2.43.0
>