[PATCH v2] drm/amd: Document device reset methods

[Alex Deucher]

On Fri, Nov 10, 2023 at 12:23 PM André Almeida <andrealmeid at igalia.com> wrote:
>
> Document what each amdgpu driver reset method does.
>
> Signed-off-by: André Almeida <andrealmeid at igalia.com>

Applied with Randy's suggestion.  Thanks!

Alex

> ---
> v2: Add more details and small correction (Alex)
>
>  drivers/gpu/drm/amd/amdgpu/amdgpu.h | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index a79d53bdbe13..c4675572f907 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -504,6 +504,31 @@ struct amdgpu_allowed_register_entry {
>         bool grbm_indexed;
>  };
>
> +/**
> + * enum amd_reset_method - Methods for resetting AMD GPU devices
> + *
> + * @AMD_RESET_METHOD_NONE: The device will not be reset.
> + * @AMD_RESET_LEGACY: Method reserved for SI, CIK and VI ASICs.
> + * @AMD_RESET_MODE0: Reset the entire ASIC. Not currently available for the
> + *                   any device.
> + * @AMD_RESET_MODE1: Resets all IP blocks on the ASIC (SDMA, GFX, VCN, etc.)
> + *                   individually. Suitable only for some discrete GPU, not
> + *                   available for all ASICs.
> + * @AMD_RESET_MODE2: Resets a lesser level of IPs compared to MODE1. Which IPs
> + *                   are reset depends on the ASIC. Notably doesn't reset IPs
> + *                   shared with the CPU on APUs or the memory controllers (so
> + *                   VRAM is not lost). Not available on all ASICs.
> + * @AMD_RESET_BACO: BACO (Bus Alive, Chip Off) method powers off and on the card
> + *                  but without powering off the PCI bus. Suitable only for
> + *                  discrete GPUs.
> + * @AMD_RESET_PCI: Does a full bus reset using core Linux subsystem PCI reset
> + *                 and does a secondary bus reset or FLR, depending on what the
> + *                 underlying hardware supports.
> + *
> + * Methods available for AMD GPU driver for resetting the device. Not all
> + * methods are suitable for every device. User can overwrite the method using
> + * module parameter `reset_method`.
> + */
>  enum amd_reset_method {
>         AMD_RESET_METHOD_NONE = -1,
>         AMD_RESET_METHOD_LEGACY = 0,
> --
> 2.42.1
>