[PATCH] drm/amdgpu: disable cstate properly for driver reloading scenario

[Lazar, Lijo]

On 3/2/2023 12:28 PM, Evan Quan wrote:
> Gpu reset might be needed during driver reloading. To guard that(gpu
> reset) work, df cstate needs to be disabled properly.
> 
> Signed-off-by: Evan Quan <evan.quan at amd.com>
> Change-Id: I5c074c265c0b08a67b6934ae1ad9aa3fed245461
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 51bbeaa1f311..3c854461ef32 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -2816,6 +2816,15 @@ static int amdgpu_device_ip_fini_early(struct amdgpu_device *adev)
>   	amdgpu_device_set_pg_state(adev, AMD_PG_STATE_UNGATE);
>   	amdgpu_device_set_cg_state(adev, AMD_CG_STATE_UNGATE);
>   
> +	/*
> +	 * Get df cstate disabled properly on driver unloading.
> +	 * Since on the succeeding driver reloading, gpu reset might
> +	 * be required. And cstate disabled is a prerequisite for
> +	 * that(gpu reset).
> +	 */
> +	if (amdgpu_dpm_set_df_cstate(adev, DF_CSTATE_DISALLOW))
> +		dev_warn(adev->dev, "Failed to disallow df cstate");
> +

This looks more like a firmware bug. Driver sends the Unload message to 
FW. In that case FW should disable all features including C-state.

Thanks,
Lijo

>   	amdgpu_amdkfd_suspend(adev, false);
>   
>   	/* Workaroud for ASICs need to disable SMC first */