[PATCH] drm/amdgpu: disable mcbp if parameter zero is set

[Alex Deucher]

On Mon, Aug 7, 2023 at 11:18 PM <jiadong.zhu at amd.com> wrote:
>
> From: Jiadong Zhu <Jiadong.Zhu at amd.com>
>
> The parameter amdgpu_mcbp shall have priority against the default value
> calculated from the chip version.
> User could disable mcbp by setting the parameter mcbp as zero.
>
> Signed-off-by: Jiadong Zhu <Jiadong.Zhu at amd.com>

I think this should be expanded to disable the sw rings as well since
they presumably won't work correctly without MCBP.

Alex

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 7314529553f6..615669dcabc2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -3699,10 +3699,11 @@ static void amdgpu_device_set_mcbp(struct amdgpu_device *adev)
>  {
>         if (amdgpu_mcbp == 1)
>                 adev->gfx.mcbp = true;
> -
> -       if ((adev->ip_versions[GC_HWIP][0] >= IP_VERSION(9, 0, 0)) &&
> -           (adev->ip_versions[GC_HWIP][0] < IP_VERSION(10, 0, 0)) &&
> -           adev->gfx.num_gfx_rings)
> +       else if (amdgpu_mcbp == 0)
> +               adev->gfx.mcbp = false;
> +       else if ((adev->ip_versions[GC_HWIP][0] >= IP_VERSION(9, 0, 0)) &&
> +                (adev->ip_versions[GC_HWIP][0] < IP_VERSION(10, 0, 0)) &&
> +                adev->gfx.num_gfx_rings)
>                 adev->gfx.mcbp = true;
>
>         if (amdgpu_sriov_vf(adev))
> --
> 2.25.1
>