[PATCH] drm/amdgpu: fix a potential GPU hang on cyan skillfish

[Lazar, Lijo]

On 1/28/2022 4:13 PM, Lang Yu wrote:
> We observed a GPU hang when querying GMC CG state(i.e.,
> cat amdgpu_pm_info) on cyan skillfish. Acctually, cyan
> skillfish doesn't support any CG features.
> 
> Just prevent cyan skillfish from accessing GMC CG registers.
> 
> Signed-off-by: Lang Yu <Lang.Yu at amd.com>

Reviewed-by: Lijo Lazar <lijo.lazar at amd.com>

Thanks,
Lijo

> ---
>   drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> index 73ab0eebe4e2..bddaf2417344 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> @@ -1156,6 +1156,9 @@ static void gmc_v10_0_get_clockgating_state(void *handle, u32 *flags)
>   {
>   	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
>   
> +	if (adev->ip_versions[GC_HWIP][0] == IP_VERSION(10, 1, 3))
> +		return;
> +
>   	adev->mmhub.funcs->get_clockgating(adev, flags);
>   
>   	if (adev->ip_versions[ATHUB_HWIP][0] >= IP_VERSION(2, 1, 0))
>