On Tue, 23 Jul 2013, Mathias Nyman wrote:
> Make the Linux xHCI driver automatically try to switchover the EHCI ports to
> xHCI when an Intel xHCI host is detected, and it also finds an Intel EHCI host.
>
> This means we will no longer have to add Intel xHCI hosts to a quirks list when
> the PCI device IDs change. Simply continuing to add new Intel xHCI PCI device
> IDs to the quirks list is not sustainable.
>
> During suspend ports may be swicthed back to EHCI by BIOS and not properly
> restored to xHCI at resume. Previously both EHCI and xHCI resume functions
> switched ports back to XHCI, but it's enough to do it in xHCI only
> because the hub driver doesn't start running again until after both hosts are resumed.
>
> Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
> -void usb_enable_xhci_ports(struct pci_dev *xhci_pdev)
> +void usb_enable_intel_xhci_ports(struct pci_dev *xhci_pdev)
> {
> u32 ports_available;
> + bool ehci_found = false;
> + struct pci_dev *companion = NULL;
> +
> + /* make sure an intel EHCI controller exists */
> + for_each_pci_dev(companion) {
> + if (companion->class == PCI_CLASS_SERIAL_USB_EHCI &&
> + companion->vendor == PCI_VENDOR_ID_INTEL) {
> + ehci_found = true;
> + break;
> + }
> + }
> +
> + if (!ehci_found)
> + return;
>
> /* Don't switchover the ports if the user hasn't compiled the xHCI
> * driver. Otherwise they will see "dead" USB ports that don't power
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -250,13 +250,15 @@ static int xhci_pci_resume(struct usb_hcd *hcd, bool hibernated)
> * writers.
> *
> * Unconditionally switch the ports back to xHCI after a system resume.
> - * We can't tell whether the EHCI or xHCI controller will be resumed
> - * first, so we have to do the port switchover in both drivers. Writing
> - * a '1' to the port switchover registers should have no effect if the
> - * port was already switched over.
> + * It should not matter whether the EHCI or xHCI controller is
> + * resumed first. It's enough to do the switchover in xHCI because
> + * USB core won't notice anything as the hub driver doesn't start
> + * running again until after all the devices (including both EHCI and
> + * xHCI host controllers) have been resumed.
> */
> - if (usb_is_intel_switchable_xhci(pdev))
> - usb_enable_xhci_ports(pdev);
> +
> + if (pdev->vendor == PCI_VENDOR_ID_INTEL)
> + usb_enable_intel_xhci_ports(pdev);
Short and sweet; I like it!
Alan Stern
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