[PATCH] drm/amdgpu: limit VCN instance number to 1 for NAVY_FLOUNDER

[Chen, Guchun]

Hi Lijo,

Alex has a following fix "85db7fcb2e53 drm/amdgpu: get VCN harvest information from IP discovery table" to fix that logic.

For other ASCIs like DIMGREY_CAVEFISH and BEIGE_GOBY, its instance num is 1, match with VBIOS discovery table. So there is no need to handle it.

Regards,
Guchun

-----Original Message-----
From: Lazar, Lijo <Lijo.Lazar at amd.com> 
Sent: Thursday, October 21, 2021 5:45 PM
To: Chen, Guchun <Guchun.Chen at amd.com>; amd-gfx at lists.freedesktop.org; Koenig, Christian <Christian.Koenig at amd.com>; Pan, Xinhui <Xinhui.Pan at amd.com>; Deucher, Alexander <Alexander.Deucher at amd.com>; Liu, Leo <Leo.Liu at amd.com>
Subject: Re: [PATCH] drm/amdgpu: limit VCN instance number to 1 for NAVY_FLOUNDER



On 10/21/2021 12:45 PM, Guchun Chen wrote:
> VCN instance 1 is power gated permanently by SMU.
> 
> Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1743
> 
> Fixes: f6b6d7d6bc2d("drm/amdgpu/vcn: remove manual instance setting")

Nice find. Looking at the fix, the logic is already broken by
5e26e52adb46("drm/amdgpu/vcn3.0: convert to IP version checking")

Any ASIC other than Sienna which has same VCN IP version (3.0.0) may be broken. Any more extra checks?

Thanks,
Lijo

> Signed-off-by: Guchun Chen <guchun.chen at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/vcn_v3_0.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/vcn_v3_0.c 
> b/drivers/gpu/drm/amd/amdgpu/vcn_v3_0.c
> index dbfd92984655..4848922667f2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/vcn_v3_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/vcn_v3_0.c
> @@ -103,6 +103,15 @@ static int vcn_v3_0_early_init(void *handle)
>   			adev->vcn.num_enc_rings = 0;
>   		else
>   			adev->vcn.num_enc_rings = 2;
> +
> +		/*
> +		 * Fix ME.
> +		 * VCN instance number is limited to 1 for below ASIC due to
> +		 * VCN instnace 1 is permanently power gated.
> +		 */
> +		if ((adev->ip_versions[UVD_HWIP][0] == IP_VERSION(3, 0, 0)) &&
> +			(adev->ip_versions[GC_HWIP][0] == IP_VERSION(10, 3, 2)))
> +			adev->vcn.num_vcn_inst = 1;
>   	}
>   
>   	vcn_v3_0_set_dec_ring_funcs(adev);
>