[PATCH] drm/amdgpu: Adjust logic in amdgpu_device_partner_bandwidth()

[Alex Deucher]

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On Thu, May 16, 2024 at 11:42 AM Alex Deucher <alexander.deucher at amd.com> wrote:
>
> Use current speed/width on devices which don't support
> dynamic PCIe switching.
>
> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3289
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index e72e774d17e6a..f0011dac589d2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -5946,13 +5946,18 @@ static void amdgpu_device_partner_bandwidth(struct amdgpu_device *adev,
>         *speed = PCI_SPEED_UNKNOWN;
>         *width = PCIE_LNK_WIDTH_UNKNOWN;
>
> -       while ((parent = pci_upstream_bridge(parent))) {
> -               /* skip upstream/downstream switches internal to dGPU*/
> -               if (parent->vendor == PCI_VENDOR_ID_ATI)
> -                       continue;
> -               *speed = pcie_get_speed_cap(parent);
> -               *width = pcie_get_width_cap(parent);
> -               break;
> +       if (amdgpu_device_pcie_dynamic_switching_supported(adev)) {
> +               while ((parent = pci_upstream_bridge(parent))) {
> +                       /* skip upstream/downstream switches internal to dGPU*/
> +                       if (parent->vendor == PCI_VENDOR_ID_ATI)
> +                               continue;
> +                       *speed = pcie_get_speed_cap(parent);
> +                       *width = pcie_get_width_cap(parent);
> +                       break;
> +               }
> +       } else {
> +               /* use the current speeds rather than max if switching is not supported */
> +               pcie_bandwidth_available(adev->pdev, NULL, speed, width);
>         }
>  }
>
> --
> 2.45.0
>