[PATCH v4 09/11] drm/xe/configfs: Check if device was preconfigured

[John Harrison]

On 7/27/2025 10:20 AM, Michal Wajdeczko wrote:
> Since device configuration using configfs could be prepared long
> time prior the driver load, add a debug log whether the current
> device driver probe is using custom or default settings.
>
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Reviewed-by: John Harrison <John.C.Harrison at Intel.com>

> ---
> v2: make function void, rename helpers (Lucas) and rebased
> ---
>   drivers/gpu/drm/xe/xe_configfs.c | 25 +++++++++++++++++++++++++
>   drivers/gpu/drm/xe/xe_configfs.h |  2 ++
>   drivers/gpu/drm/xe/xe_pci.c      |  3 +++
>   3 files changed, 30 insertions(+)
>
> diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
> index 60d89d3ef656..73fb6812efe0 100644
> --- a/drivers/gpu/drm/xe/xe_configfs.c
> +++ b/drivers/gpu/drm/xe/xe_configfs.c
> @@ -108,6 +108,11 @@ static void set_device_defaults(struct xe_config_device *config)
>   	*config = device_defaults;
>   }
>   
> +static bool config_device_is_default(const struct xe_config_device *config)
> +{
> +	return !memcmp(config, &device_defaults, sizeof(*config));
> +}
> +
>   struct engine_info {
>   	const char *cls;
>   	u64 mask;
> @@ -333,6 +338,26 @@ static struct xe_config_group_device *find_xe_config_group_device(struct pci_dev
>   	return to_xe_config_group_device(item);
>   }
>   
> +/**
> + * xe_configfs_check_device() - Test if device was configured by configfs
> + * @pdev: the &pci_dev device to test
> + *
> + * Try to find the configfs group that belongs to the specified pci device
> + * and print a diagnostic message if found.
> + */
> +void xe_configfs_check_device(struct pci_dev *pdev)
> +{
> +	struct xe_config_group_device *dev = find_xe_config_group_device(pdev);
> +
> +	if (!dev)
> +		return;
> +
> +	pci_dbg(pdev, "found %s settings in configfs\n",
> +		config_device_is_default(&dev->config) ? "default" : "custom");
> +
> +	config_group_put(&dev->group);
> +}
> +
>   /**
>    * xe_configfs_get_survivability_mode - get configfs survivability mode attribute
>    * @pdev: pci device
> diff --git a/drivers/gpu/drm/xe/xe_configfs.h b/drivers/gpu/drm/xe/xe_configfs.h
> index fb8764008089..fa4ea7f0c375 100644
> --- a/drivers/gpu/drm/xe/xe_configfs.h
> +++ b/drivers/gpu/drm/xe/xe_configfs.h
> @@ -13,12 +13,14 @@ struct pci_dev;
>   #if IS_ENABLED(CONFIG_CONFIGFS_FS)
>   int xe_configfs_init(void);
>   void xe_configfs_exit(void);
> +void xe_configfs_check_device(struct pci_dev *pdev);
>   bool xe_configfs_get_survivability_mode(struct pci_dev *pdev);
>   void xe_configfs_clear_survivability_mode(struct pci_dev *pdev);
>   u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev);
>   #else
>   static inline int xe_configfs_init(void) { return 0; }
>   static inline void xe_configfs_exit(void) { }
> +static inline void xe_configfs_check_device(struct pci_dev *pdev) { }
>   static inline bool xe_configfs_get_survivability_mode(struct pci_dev *pdev) { return false; }
>   static inline void xe_configfs_clear_survivability_mode(struct pci_dev *pdev) { }
>   static inline u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev) { return U64_MAX; }
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index 52d46c66ae1e..9ce6e6dca5bc 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -17,6 +17,7 @@
>   
>   #include "display/xe_display.h"
>   #include "regs/xe_gt_regs.h"
> +#include "xe_configfs.h"
>   #include "xe_device.h"
>   #include "xe_drv.h"
>   #include "xe_gt.h"
> @@ -771,6 +772,8 @@ static int xe_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>   	struct xe_device *xe;
>   	int err;
>   
> +	xe_configfs_check_device(pdev);
> +
>   	if (desc->require_force_probe && !id_forced(pdev->device)) {
>   		dev_info(&pdev->dev,
>   			 "Your graphics device %04x is not officially supported\n"