diff options
Diffstat (limited to 'drivers/usb/host/ohci-pci.c')
| -rw-r--r-- | drivers/usb/host/ohci-pci.c | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/drivers/usb/host/ohci-pci.c b/drivers/usb/host/ohci-pci.c index ca62cb583221..15013f4519ad 100644 --- a/drivers/usb/host/ohci-pci.c +++ b/drivers/usb/host/ohci-pci.c @@ -202,6 +202,42 @@ static int __devinit ohci_pci_start (struct usb_hcd *hcd) return ret; } +#if defined(CONFIG_USB_PERSIST) && (defined(CONFIG_USB_EHCI_HCD) || \ + defined(CONFIG_USB_EHCI_HCD_MODULE)) + +/* Following a power loss, we must prepare to regain control of the ports + * we used to own. This means turning on the port power before ehci-hcd + * tries to switch ownership. + * + * This isn't a 100% perfect solution. On most systems the OHCI controllers + * lie at lower PCI addresses than the EHCI controller, so they will be + * discovered (and hence resumed) first. But there is no guarantee things + * will always work this way. If the EHCI controller is resumed first and + * the OHCI ports are unpowered, then the handover will fail. + */ +static void prepare_for_handover(struct usb_hcd *hcd) +{ + struct ohci_hcd *ohci = hcd_to_ohci(hcd); + int port; + + /* Here we "know" root ports should always stay powered */ + ohci_dbg(ohci, "powerup ports\n"); + for (port = 0; port < ohci->num_ports; port++) + ohci_writel(ohci, RH_PS_PPS, + &ohci->regs->roothub.portstatus[port]); + + /* Flush those writes */ + ohci_readl(ohci, &ohci->regs->control); + msleep(20); +} + +#else + +static inline void prepare_for_handover(struct usb_hcd *hcd) +{ } + +#endif /* CONFIG_USB_PERSIST etc. */ + #ifdef CONFIG_PM static int ohci_pci_suspend (struct usb_hcd *hcd, pm_message_t message) @@ -241,7 +277,10 @@ static int ohci_pci_suspend (struct usb_hcd *hcd, pm_message_t message) static int ohci_pci_resume (struct usb_hcd *hcd) { set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags); - usb_hcd_resume_root_hub(hcd); + + /* FIXME: we should try to detect loss of VBUS power here */ + prepare_for_handover(hcd); + return 0; } |