Re: [PATCH v4] PCI/PTM: Enable PTM only if it advertises a role

[Lukas Wunner <lukas@wunner.de>]

On Tue, Nov 11, 2025 at 07:10:48AM +0100, Mika Westerberg wrote:
> +++ b/drivers/pci/pcie/ptm.c
> @@ -144,6 +147,38 @@ static int __pci_enable_ptm(struct pci_dev *dev)
>  			return -EINVAL;
>  	}
>  
> +	switch (pci_pcie_type(dev)) {
> +	case PCI_EXP_TYPE_ROOT_PORT:
> +		/*
> +		 * Root Port must declare Root Capable if we want to enable
> +		 * PTM for it.
> +		 */
> +		if (!dev->ptm_root)
> +			return -EINVAL;
> +		break;
> +	case PCI_EXP_TYPE_UPSTREAM:
> +		/*
> +		 * Switch Upstream Ports must at least declare Responder
> +		 * Capable if we want to enable PTM for it.
> +		 */
> +		if (!dev->ptm_responder)
> +			return -EINVAL;
> +		break;
> +
> +	case PCI_EXP_TYPE_ENDPOINT:
> +	case PCI_EXP_TYPE_LEG_END:
> +		/*
> +		 * PCIe Endpoint must declare Requester Capable before we
> +		 * can enable PTM for it.
> +		 */
> +		if (!dev->ptm_requester)
> +			return -EINVAL;
> +		break;
> +
> +	default:
> +		return -EINVAL;
> +	}

Nit:  Inconsistent newline before and after the endpoint case,
the other cases don't have that.  (Can probably be fixed up by
Bjorn when applying.)

Thanks,

Lukas