[PATCH] drm/amdgpu: Improve RAS documentation

[Zhao, Yong]

See two wording comments inline. With that

Reviewed-by: Yong Zhao<yong.zhao at amd.com>

On 2019-10-30 2:41 p.m., Alex Deucher wrote:
> Clarify some areas, clean up formatting, add section for
> unrecoverable error handling.
>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>   Documentation/gpu/amdgpu.rst            | 35 ++++++++++++++++++++++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 40 ++++++++++++++++++++-----
>   2 files changed, 68 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/gpu/amdgpu.rst b/Documentation/gpu/amdgpu.rst
> index 5b9eaf23558e..1c08d64970ee 100644
> --- a/Documentation/gpu/amdgpu.rst
> +++ b/Documentation/gpu/amdgpu.rst
> @@ -82,12 +82,21 @@ AMDGPU XGMI Support
>   AMDGPU RAS Support
>   ==================
>   
> +The AMDGPU RAS interfaces are exposed via sysfs (for informational queries) and
> +debugfs (for error injection).
> +
>   RAS debugfs/sysfs Control and Error Injection Interfaces
>   --------------------------------------------------------
>   
>   .. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
>      :doc: AMDGPU RAS debugfs control interface
>   
> +RAS Reboot Behavior for Unrecoverable Errors
> +--------------------------------------------------------
> +
> +.. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> +   :doc: AMDGPU RAS Reboot Behavior for Unrecoverable Errors
> +
>   RAS Error Count sysfs Interface
>   -------------------------------
>   
> @@ -109,6 +118,32 @@ RAS VRAM Bad Pages sysfs Interface
>   .. kernel-doc:: drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
>      :internal:
>   
> +Sample Code
> +-----------
> +Sample code for testing error injection can be found here:
> +https://cgit.freedesktop.org/mesa/drm/tree/tests/amdgpu/ras_tests.c
> +
> +This is part of the libdrm amdgpu unit tests which cover several areas of the GPU.
> +There are four sets of tests:
> +
> +RAS Basic Test
> +
> +The test verifies the RAS feature enabled status and makes sure the necessary sysfs and debugfs files
> +are present.
> +
> +RAS Query Test
> +
> +This test will check the RAS availability and enablement status for each supported IP block as well as
> +the error counts.

This test checks

> +
> +RAS Inject Test
> +
> +This test injects errors for each IP.
> +
> +RAS Disable Test
> +
> +This tests disabling of RAS features for each IP block.

This tests tests disabling

> +
>   
>   GPU Power/Thermal Controls and Monitoring
>   =========================================
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> index dab90c280476..404483437bd3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> @@ -220,7 +220,7 @@ static struct ras_manager *amdgpu_ras_find_obj(struct amdgpu_device *adev,
>    * As their names indicate, inject operation will write the
>    * value to the address.
>    *
> - * Second member: struct ras_debug_if::op.
> + * The second member: struct ras_debug_if::op.
>    * It has three kinds of operations.
>    *
>    * - 0: disable RAS on the block. Take ::head as its data.
> @@ -228,14 +228,20 @@ static struct ras_manager *amdgpu_ras_find_obj(struct amdgpu_device *adev,
>    * - 2: inject errors on the block. Take ::inject as its data.
>    *
>    * How to use the interface?
> - * programs:
> - * copy the struct ras_debug_if in your codes and initialize it.
> - * write the struct to the control node.
> + *
> + * Programs
> + *
> + * Copy the struct ras_debug_if in your codes and initialize it.
> + * Write the struct to the control node.
> + *
> + * Shells
>    *
>    * .. code-block:: bash
>    *
>    *	echo op block [error [sub_block address value]] > .../ras/ras_ctrl
>    *
> + * Parameters:
> + *
>    * op: disable, enable, inject
>    *	disable: only block is needed
>    *	enable: block and error are needed
> @@ -265,8 +271,10 @@ static struct ras_manager *amdgpu_ras_find_obj(struct amdgpu_device *adev,
>    * /sys/class/drm/card[0/1/2...]/device/ras/[gfx/sdma/...]_err_count
>    *
>    * .. note::
> - *	Operation is only allowed on blocks which are supported.
> + *	Operations are only allowed on blocks which are supported.
>    *	Please check ras mask at /sys/module/amdgpu/parameters/ras_mask
> + *	to see which blocks support RAS on a particular asic.
> + *
>    */
>   static ssize_t amdgpu_ras_debugfs_ctrl_write(struct file *f, const char __user *buf,
>   		size_t size, loff_t *pos)
> @@ -322,7 +330,7 @@ static ssize_t amdgpu_ras_debugfs_ctrl_write(struct file *f, const char __user *
>    * DOC: AMDGPU RAS debugfs EEPROM table reset interface
>    *
>    * Some boards contain an EEPROM which is used to persistently store a list of
> - * bad pages containing ECC errors detected in vram.  This interface provides
> + * bad pages which experiences ECC errors in vram.  This interface provides
>    * a way to reset the EEPROM, e.g., after testing error injection.
>    *
>    * Usage:
> @@ -362,7 +370,7 @@ static const struct file_operations amdgpu_ras_debugfs_eeprom_ops = {
>   /**
>    * DOC: AMDGPU RAS sysfs Error Count Interface
>    *
> - * It allows user to read the error count for each IP block on the gpu through
> + * It allows the user to read the error count for each IP block on the gpu through
>    * /sys/class/drm/card[0/1/2...]/device/ras/[gfx/sdma/...]_err_count
>    *
>    * It outputs the multiple lines which report the uncorrected (ue) and corrected
> @@ -1027,6 +1035,24 @@ static int amdgpu_ras_sysfs_remove_all(struct amdgpu_device *adev)
>   }
>   /* sysfs end */
>   
> +/**
> + * DOC: AMDGPU RAS Reboot Behavior for Unrecoverable Errors
> + *
> + * Normally when there is an uncorrectable error, the driver will reset
> + * the GPU to recover.  However, in the event of an unrecoverable error,
> + * the driver provides an interface to reboot the system automatically
> + * in that event.
> + *
> + * The following file in debugfs provides that interface:
> + * /sys/kernel/debug/dri/[0/1/2...]/ras/auto_reboot
> + *
> + * Usage:
> + *
> + * .. code-block:: bash
> + *
> + *	echo true > .../ras/auto_reboot
> + *
> + */
>   /* debugfs begin */
>   static void amdgpu_ras_debugfs_create_ctrl_node(struct amdgpu_device *adev)
>   {