diff options
Diffstat (limited to 'drivers/usb/host')
| -rw-r--r-- | drivers/usb/host/ehci-pci.c | 28 |
1 files changed, 25 insertions, 3 deletions
diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c index 7a1ffe5e28..991b19998b 100644 --- a/drivers/usb/host/ehci-pci.c +++ b/drivers/usb/host/ehci-pci.c @@ -54,9 +54,31 @@ static pci_dev_t ehci_find_class(int index) bdf += PCI_BDF(0, 0, 1)) { pci_read_config_dword(bdf, PCI_CLASS_REVISION, &class); - if ((class >> 8 == PCI_CLASS_SERIAL_USB_EHCI) - && !index--) - return bdf; + class >>= 8; + /* + * Here be dragons! In case we have multiple + * PCI EHCI controllers, this function will + * be called multiple times as well. This + * function will scan the PCI busses, always + * starting from bus 0, device 0, function 0, + * until it finds an USB controller. The USB + * stack gives us an 'index' of a controller + * that is currently being registered, which + * is a number, starting from 0 and growing + * in ascending order as controllers are added. + * To avoid probing the same controller in tne + * subsequent runs of this function, we will + * skip 'index - 1' detected controllers and + * report the index'th controller. + */ + if (class != PCI_CLASS_SERIAL_USB_EHCI) + continue; + if (index) { + index--; + continue; + } + /* Return index'th controller. */ + return bdf; } } } |