[PATCH] amdgpu/gmc_v9: Warn if SDPIF_MMIO_CNTRL_0 is not set

[Alex Deucher]

On Mon, Sep 14, 2020 at 12:55 AM Shirish S <shirish.s at amd.com> wrote:
>
> With IOMMU enabled, if SDPIF_MMIO_CNTRL_0 is not set
> appropriately the system hangs without any trace
> during S3.
>
> To ease debug and to ensure that the failure, if any,
> was caused by a race conditions that disabled write access to
> SDPIF_MMIO_CNTRL_0 register, warn the user about it.
>
> Signed-off-by: Shirish S <shirish.s at amd.com>

Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> index d0645ad3446e..fc2d88dbe828 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> @@ -1546,8 +1546,11 @@ static void gmc_v9_0_init_golden_registers(struct amdgpu_device *adev)
>   */
>  void gmc_v9_0_restore_registers(struct amdgpu_device *adev)
>  {
> -       if (adev->asic_type == CHIP_RAVEN)
> +       if (adev->asic_type == CHIP_RAVEN) {
>                 WREG32_SOC15(DCE, 0, mmDCHUBBUB_SDPIF_MMIO_CNTRL_0, adev->gmc.sdpif_register);
> +               WARN_ON(adev->gmc.sdpif_register !=
> +                       RREG32_SOC15(DCE, 0, mmDCHUBBUB_SDPIF_MMIO_CNTRL_0);
> +       }
>  }
>
>  /**
> --
> 2.17.1
>
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