Re: [PATCH] drm/xe: Move debugfs GT attributes under tile directory

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

On Mon, Jul 14, 2025 at 09:36:45PM +0200, Michal Wajdeczko wrote:
> While in sysfs we are correctly trying to reflect the hardware
> architecture and we expose GT attributes in per tile hierarchy,
> in debugfs we expose GT attributes at flat level, without tiles.
> 
> Create debugfs directories to represent each tile and move GT
> attributes under matching parent tile directory. To not break
> existing debugfs tools, create symlink under old location:
> 
>  /sys/kernel/debug/dri/0000:00:02.0/
>  ├── ...
>  ├── gt0 -> tile0/gt0
>  ├── gt1 -> tile0/gt1
>  ├── tile0
>  │   ├── gt0
>  │   │   ├── ...
>  │   ├── gt1
>  │   │   ├── ...
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_debugfs.c      | 22 ++++++++++++++++++++++
>  drivers/gpu/drm/xe/xe_device_types.h |  3 +++
>  drivers/gpu/drm/xe/xe_gt_debugfs.c   | 14 +++++++++++++-
>  3 files changed, 38 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
> index 26e9d146ccbf..129186f4193b 100644
> --- a/drivers/gpu/drm/xe/xe_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_debugfs.c
> @@ -247,14 +247,33 @@ static const struct file_operations atomic_svm_timeslice_ms_fops = {
>  	.write = atomic_svm_timeslice_ms_set,
>  };
>  
> +static void create_tile_debugfs(struct xe_tile *tile, struct dentry *root)
> +{
> +	char name[8];
> +
> +	snprintf(name, sizeof(name), "tile%u", tile->id);
> +	tile->debugfs = debugfs_create_dir(name, root);
> +	if (IS_ERR(tile->debugfs))
> +		return;
> +
> +	/*
> +	 * Store the xe_tile pointer as private data of the tile/ directory
> +	 * node so other tile specific attributes under that directory may
> +	 * refer to it by looking at its parent node private data.
> +	 */
> +	tile->debugfs->d_inode->i_private = tile;
> +}
> +
>  void xe_debugfs_register(struct xe_device *xe)
>  {
>  	struct ttm_device *bdev = &xe->ttm;
>  	struct drm_minor *minor = xe->drm.primary;
>  	struct dentry *root = minor->debugfs_root;
>  	struct ttm_resource_manager *man;
> +	struct xe_tile *tile;
>  	struct xe_gt *gt;
>  	u32 mem_type;
> +	u8 tile_id;
>  	u8 id;
>  
>  	drm_debugfs_create_files(debugfs_list,
> @@ -288,6 +307,9 @@ void xe_debugfs_register(struct xe_device *xe)
>  	if (man)
>  		ttm_resource_manager_create_debugfs(man, root, "stolen_mm");
>  
> +	for_each_tile(tile, xe, tile_id)
> +		create_tile_debugfs(tile, root);
> +
>  	for_each_gt(gt, xe, id)
>  		xe_gt_debugfs_register(gt);
>  
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index d4d2c6854790..98ce1255f1d0 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -255,6 +255,9 @@ struct xe_tile {
>  
>  	/** @sysfs: sysfs' kobj used by xe_tile_sysfs */
>  	struct kobject *sysfs;
> +
> +	/** @debugfs: debugfs directory associated with this tile */
> +	struct dentry *debugfs;
>  };
>  
>  /**
> diff --git a/drivers/gpu/drm/xe/xe_gt_debugfs.c b/drivers/gpu/drm/xe/xe_gt_debugfs.c
> index 848618acdca8..061a81f82e76 100644
> --- a/drivers/gpu/drm/xe/xe_gt_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_gt_debugfs.c
> @@ -388,13 +388,18 @@ void xe_gt_debugfs_register(struct xe_gt *gt)
>  {
>  	struct xe_device *xe = gt_to_xe(gt);
>  	struct drm_minor *minor = gt_to_xe(gt)->drm.primary;
> +	struct dentry *parent = gt->tile->debugfs;
>  	struct dentry *root;
> +	char symlink[16];
>  	char name[8];
>  
>  	xe_gt_assert(gt, minor->debugfs_root);
>  
> +	if (IS_ERR(parent))
> +		return;
> +
>  	snprintf(name, sizeof(name), "gt%d", gt->info.id);
> -	root = debugfs_create_dir(name, minor->debugfs_root);
> +	root = debugfs_create_dir(name, parent);
>  	if (IS_ERR(root)) {
>  		drm_warn(&xe->drm, "Create GT directory failed");
>  		return;
> @@ -426,4 +431,11 @@ void xe_gt_debugfs_register(struct xe_gt *gt)
>  		xe_gt_sriov_pf_debugfs_register(gt, root);
>  	else if (IS_SRIOV_VF(xe))
>  		xe_gt_sriov_vf_debugfs_register(gt, root);
> +
> +	/*
> +	 * Backwards compatibility only: create a link for the legacy clients
> +	 * who may expect gt/ directory at the root level, not the tile level.
> +	 */
> +	snprintf(symlink, sizeof(symlink), "tile%u/%s", gt->tile->id, name);
> +	debugfs_create_symlink(name, minor->debugfs_root, symlink);

oh, this is why IGT is happy :)

later we can change IGT and then remove this entirely...

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

>  }
> -- 
> 2.47.1
>