diff options
Diffstat (limited to 'drivers/usb/host/ehci-hub.c')
| -rw-r--r-- | drivers/usb/host/ehci-hub.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c index c4f6a2559a98..efe30e3be22f 100644 --- a/drivers/usb/host/ehci-hub.c +++ b/drivers/usb/host/ehci-hub.c @@ -745,12 +745,13 @@ int ehci_hub_control( unsigned selector; /* - * Avoid underflow while calculating (wIndex & 0xff) - 1. - * The compiler might deduce that wIndex can never be 0 and then - * optimize away the tests for !wIndex below. + * Avoid out-of-bounds values while calculating the port index + * from wIndex. The compiler doesn't like pointers to invalid + * addresses, even if they are never used. */ - temp = wIndex & 0xff; - temp -= (temp > 0); + temp = (wIndex - 1) & 0xff; + if (temp >= HCS_N_PORTS_MAX) + temp = 0; status_reg = &ehci->regs->port_status[temp]; hostpc_reg = &ehci->regs->hostpc[temp]; |