[PATCH] drm/amdgpu: Workaround RCC_DEV0_EPF0_STRAP0 access issue for SRIOV

[Alex Deucher]

On Fri, Sep 11, 2020 at 6:03 PM Rohit Khaire <rohit.khaire at amd.com> wrote:
>
> Signed-off-by: Rohit Khaire <rohit.khaire at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c b/drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c
> index 7429f30398b9..fdfa075e6d5a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c
> +++ b/drivers/gpu/drm/amd/amdgpu/nbio_v2_3.c
> @@ -51,8 +51,20 @@ static void nbio_v2_3_remap_hdp_registers(struct amdgpu_device *adev)
>
>  static u32 nbio_v2_3_get_rev_id(struct amdgpu_device *adev)
>  {
> -       u32 tmp = RREG32_SOC15(NBIO, 0, mmRCC_DEV0_EPF0_STRAP0);
> +       u32 tmp;
>
> +       /*
> +        * On SRIOV VF RCC_DEV0_EPF0_STRAP is blocked.
> +        * So we read rev_id from PCI config space.
> +        */
> +       if (amdgpu_sriov_vf(adev)) {
> +               pci_read_config_dword(adev->pdev, PCI_REVISION_ID, &tmp);

This is not going to do what you want.  The pci revision id is not the
same as the ati rev id.  If you actually want the pci revision id, we
already have it in adev->pdev->revision, no need to fetch it directly.

Alex


> +               /* Revision ID is the least significant 8 bits */
> +               tmp &= 0xFF;
> +               return tmp;
> +       }
> +
> +       tmp = RREG32_SOC15(NBIO, 0, mmRCC_DEV0_EPF0_STRAP0);
>         tmp &= RCC_DEV0_EPF0_STRAP0__STRAP_ATI_REV_ID_DEV0_F0_MASK;
>         tmp >>= RCC_DEV0_EPF0_STRAP0__STRAP_ATI_REV_ID_DEV0_F0__SHIFT;
>
> --
> 2.17.1
>
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