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

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 16.05.24 um 17:05 schrieb Alex Deucher:
> 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@amd.com>

Acked-by: Christian König <christian.koenig@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);
>   	}
>   }
>