diff options
Diffstat (limited to 'drivers/usb/host/ehci-pci.c')
| -rw-r--r-- | drivers/usb/host/ehci-pci.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c index 660b80a75ca..1102ce65a3a 100644 --- a/drivers/usb/host/ehci-pci.c +++ b/drivers/usb/host/ehci-pci.c @@ -348,11 +348,50 @@ static int ehci_pci_suspend(struct usb_hcd *hcd, bool do_wakeup) return rc; } +static bool usb_is_intel_switchable_ehci(struct pci_dev *pdev) +{ + return pdev->class == PCI_CLASS_SERIAL_USB_EHCI && + pdev->vendor == PCI_VENDOR_ID_INTEL && + pdev->device == 0x1E26; +} + +static void ehci_enable_xhci_companion(void) +{ + struct pci_dev *companion = NULL; + + /* The xHCI and EHCI controllers are not on the same PCI slot */ + for_each_pci_dev(companion) { + if (!usb_is_intel_switchable_xhci(companion)) + continue; + usb_enable_xhci_ports(companion); + return; + } +} + static int ehci_pci_resume(struct usb_hcd *hcd, bool hibernated) { struct ehci_hcd *ehci = hcd_to_ehci(hcd); struct pci_dev *pdev = to_pci_dev(hcd->self.controller); + /* The BIOS on systems with the Intel Panther Point chipset may or may + * not support xHCI natively. That means that during system resume, it + * may switch the ports back to EHCI so that users can use their + * keyboard to select a kernel from GRUB after resume from hibernate. + * + * The BIOS is supposed to remember whether the OS had xHCI ports + * enabled before resume, and switch the ports back to xHCI when the + * BIOS/OS semaphore is written, but we all know we can't trust BIOS + * 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. + */ + if (usb_is_intel_switchable_ehci(pdev)) + ehci_enable_xhci_companion(); + // maybe restore FLADJ if (time_before(jiffies, ehci->next_statechange)) |