Re: [PATCH 1/1] PCI/ASPM: Add a fix for an erratum of the PI7C9X111SLB PCI-to-PCIe bridge

[Sinan Kaya <okaya@xxxxxxxxxx>]

On 11/1/2018 3:22 PM, Stefan Mätje wrote:
> + b/drivers/pci/pcie/aspm.c
> @@ -268,6 +268,15 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
>   	/* Retrain link */
>   	reg16 |= PCI_EXP_LNKCTL_RL;
>   	pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
> +	if (0x12d8 == parent->vendor && 0xe111 == parent->device) {
> +		/*
> +		 * Due to an erratum in the Pericom PI7C9X111SLB bridge in
> +		 * reverse mode the retrain link bit needs to be cleared
> +		 * again manually to allow the link training to succeed.
> +		 */
> +		reg16 &= ~PCI_EXP_LNKCTL_RL;
> +		pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
> +	}

The typical model is to abstract quirk work into quirks.c and add some
callbacks from the actual code.