Re: [PATCH v6 6/9] drm/xe/doc: Document device wedged and runtime survivability

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

On Thu, Jul 24, 2025 at 08:04:35PM +0530, Riana Tauro wrote:
> Add documentation for vendor specific device wedged recovery method
> and runtime survivability.
> 
> v2: fix documentation (Raag)
> v3: add userspace tool for firmware update (Raag)
> v4: use consistent documentation (Raag)
> 
> Signed-off-by: Riana Tauro <riana.tauro@intel.com>

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

> ---
>  Documentation/gpu/xe/index.rst             |  1 +
>  Documentation/gpu/xe/xe_device.rst         | 10 +++++++
>  Documentation/gpu/xe/xe_pcode.rst          |  6 ++--
>  drivers/gpu/drm/xe/xe_device.c             | 22 ++++++++++++++
>  drivers/gpu/drm/xe/xe_survivability_mode.c | 35 +++++++++++++++++-----
>  5 files changed, 64 insertions(+), 10 deletions(-)
>  create mode 100644 Documentation/gpu/xe/xe_device.rst
> 
> diff --git a/Documentation/gpu/xe/index.rst b/Documentation/gpu/xe/index.rst
> index 42ba6c263cd0..88b22fad880e 100644
> --- a/Documentation/gpu/xe/index.rst
> +++ b/Documentation/gpu/xe/index.rst
> @@ -25,5 +25,6 @@ DG2, etc is provided to prototype the driver.
>     xe_tile
>     xe_debugging
>     xe_devcoredump
> +   xe_device
>     xe-drm-usage-stats.rst
>     xe_configfs
> diff --git a/Documentation/gpu/xe/xe_device.rst b/Documentation/gpu/xe/xe_device.rst
> new file mode 100644
> index 000000000000..39a937b97cd3
> --- /dev/null
> +++ b/Documentation/gpu/xe/xe_device.rst
> @@ -0,0 +1,10 @@
> +.. SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +
> +.. _xe-device-wedging:
> +
> +==================
> +Xe Device Wedging
> +==================
> +
> +.. kernel-doc:: drivers/gpu/drm/xe/xe_device.c
> +   :doc: Xe Device Wedging
> diff --git a/Documentation/gpu/xe/xe_pcode.rst b/Documentation/gpu/xe/xe_pcode.rst
> index 5937ef3599b0..2a43601123cb 100644
> --- a/Documentation/gpu/xe/xe_pcode.rst
> +++ b/Documentation/gpu/xe/xe_pcode.rst
> @@ -13,9 +13,11 @@ Internal API
>  .. kernel-doc:: drivers/gpu/drm/xe/xe_pcode.c
>     :internal:
>  
> +.. _xe-survivability-mode:
> +
>  ==================
> -Boot Survivability
> +Survivability Mode
>  ==================
>  
>  .. kernel-doc:: drivers/gpu/drm/xe/xe_survivability_mode.c
> -   :doc: Xe Boot Survivability
> +   :doc: Survivability Mode
> diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
> index df29b87ffc5f..4a34b15f9527 100644
> --- a/drivers/gpu/drm/xe/xe_device.c
> +++ b/drivers/gpu/drm/xe/xe_device.c
> @@ -1157,6 +1157,28 @@ static void xe_device_wedged_fini(struct drm_device *drm, void *arg)
>  }
>  
>  /**
> + * DOC: Xe Device Wedging
> + *
> + * Xe driver uses drm device wedged uevent as documented in Documentation/gpu/drm-uapi.rst.
> + *
> + * When device is in wedged state, every IOCTL will be blocked and GT cannot be
> + * used. Certain critical errors like gt reset failure, firmware failures can cause
> + * the device to be wedged. The default recovery method for a wedged state
> + * is rebind/bus-reset.
> + *
> + * Another recovery method is vendor-specific. Below are the usecases that trigger
> + * vendor-specific drm device wedged uevent and the procedure to be performed
> + * to recover the device.
> + *
> + * Case 1: CSC firmware errors require a firmware flash to restore normal device
> + *         operation. Since firmware flash is a vendor-specific action
> + *         ``WEDGED=vendor-specific`` recovery method along with
> + *         :ref:`runtime survivability mode <xe-survivability-mode>` is used to
> + *         notify userspace. User can then initiate a firmware flash using userspace tools
> + *         like fwupd to restore device to normal situation.
> + */
> +
> +/*
>   * xe_device_set_wedged_method - Set wedged recovery method
>   * @xe: xe device instance
>   * @method: recovery method to set
> diff --git a/drivers/gpu/drm/xe/xe_survivability_mode.c b/drivers/gpu/drm/xe/xe_survivability_mode.c
> index 267d0e3fd85a..86ba767c4e44 100644
> --- a/drivers/gpu/drm/xe/xe_survivability_mode.c
> +++ b/drivers/gpu/drm/xe/xe_survivability_mode.c
> @@ -22,15 +22,18 @@
>  #define MAX_SCRATCH_MMIO 8
>  
>  /**
> - * DOC: Xe Boot Survivability
> + * DOC: Survivability Mode
>   *
> - * Boot Survivability is a software based workflow for recovering a system in a failed boot state
> + * Survivability Mode is a software based workflow for recovering a system in a failed boot state
>   * Here system recoverability is concerned with recovering the firmware responsible for boot.
>   *
> - * This is implemented by loading the driver with bare minimum (no drm card) to allow the firmware
> - * to be flashed through mei and collect telemetry. The driver's probe flow is modified
> - * such that it enters survivability mode when pcode initialization is incomplete and boot status
> - * denotes a failure.
> + * Boot Survivability
> + * ===================
> + *
> + * Boot Survivability is implemented by loading the driver with bare minimum (no drm card) to allow
> + * the firmware to be flashed through mei driver and collect telemetry. The driver's probe flow is
> + * modified such that it enters survivability mode when pcode initialization is incomplete and boot
> + * status denotes a failure.
>   *
>   * Survivability mode can also be entered manually using the survivability mode attribute available
>   * through configfs which is beneficial in several usecases. It can be used to address scenarios
> @@ -46,7 +49,7 @@
>   * Survivability mode is indicated by the below admin-only readable sysfs which provides additional
>   * debug information::
>   *
> - *	/sys/bus/pci/devices/<device>/surivability_mode
> + *	/sys/bus/pci/devices/<device>/survivability_mode
>   *
>   * Capability Information:
>   *	Provides boot status
> @@ -56,6 +59,22 @@
>   *	Provides history of previous failures
>   * Auxiliary Information
>   *	Certain failures may have information in addition to postcode information
> + *
> + * Runtime Survivability
> + * =====================
> + *
> + * Certain runtime firmware errors can cause the device to enter a wedged state
> + * (:ref:`xe-device-wedging`) requiring a firmware flash to restore normal operation.
> + * Runtime Survivability Mode indicates that a firmware flash is necessary to recover the device and
> + * is indicated by the presence of survivability mode sysfs::
> + *
> + *	/sys/bus/pci/devices/<device>/survivability_mode
> + *
> + * Survivability mode sysfs provides information about the type of survivability mode.
> + *
> + * When such errors occur, userspace is notified with the drm device wedged uevent and runtime
> + * survivability mode. User can then initiate a firmware flash using userspace tools like fwupd
> + * to restore device to normal operation.
>   */
>  
>  static u32 aux_history_offset(u32 reg_value)
> @@ -327,7 +346,7 @@ int xe_survivability_mode_runtime_enable(struct xe_device *xe)
>  
>  	xe_device_set_wedged_method(xe, DRM_WEDGE_RECOVERY_VENDOR);
>  	xe_device_declare_wedged(xe);
> -	dev_err(&pdev->dev, "Firmware update required, Refer the userspace documentation for more details!\n");
> +	dev_err(&pdev->dev, "Firmware flash required, Refer the userspace documentation for more details!\n");
>  
>  	return 0;
>  }
> -- 
> 2.47.1
>