Re: [PATCH v3 4/7] drm/xe/doc: Document device wedged and runtime survivability

[Riana Tauro <riana.tauro@intel.com>]

On 7/2/2025 7:41 PM, Riana Tauro wrote:
> Add documentation for vendor specific device wedged recovery method
> and runtime survivability.
> 
> Signed-off-by: Riana Tauro <riana.tauro@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             | 16 +++++++++++
>   drivers/gpu/drm/xe/xe_survivability_mode.c | 31 +++++++++++++++++-----
>   5 files changed, 56 insertions(+), 8 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..f9b962169919
> --- /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: 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 5defa54ccd26..d6b680abc3ae 100644
> --- a/drivers/gpu/drm/xe/xe_device.c
> +++ b/drivers/gpu/drm/xe/xe_device.c
> @@ -1119,6 +1119,22 @@ static void xe_device_wedged_fini(struct drm_device *drm, void *arg)
>   	xe_pm_runtime_put(xe);
>   }
>   
> +/**
> + * DOC: Device Wedging
> + *
> + * Xe driver uses 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 mechanism for a wedged state
> + * is re-probe (unbind + bind)
> + *
> + * However, 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.
> + */
> +
>   /**
>    * xe_device_declare_wedged - Declare device wedged
>    * @xe: xe device instance
> diff --git a/drivers/gpu/drm/xe/xe_survivability_mode.c b/drivers/gpu/drm/xe/xe_survivability_mode.c
> index e1adcb33c9b0..0dc8fd77a9f4 100644
> --- a/drivers/gpu/drm/xe/xe_survivability_mode.c
> +++ b/drivers/gpu/drm/xe/xe_survivability_mode.c
> @@ -21,15 +21,18 @@
>   #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 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
> @@ -55,6 +58,22 @@
>    *	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 non-recoverable 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>/surivability_mode

typo. Will fix in next rev

> + *
> + * 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 to restore device to normal
> + * operation.
>    */
>   
>   static u32 aux_history_offset(u32 reg_value)