3 files changed, 32 insertions, 3 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ef69c75780bf..25d298517104 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1714,6 +1714,14 @@ and is between 256 and 4096 characters. It is defined in the file
         uart6850=       [HW,OSS]
                         Format: <io>,<irq>
 
+        uhci-hcd.ignore_oc=
+                        [USB] Ignore overcurrent events (default N).
+                        Some badly-designed motherboards generate lots of
+                        bogus events, for ports that aren't wired to
+                        anything.  Set this parameter to avoid log spamming.
+                        Note that genuine overcurrent events won't be
+                        reported either.
+
         usbhid.mousepoll=
                         [USBHID] The interval which mice are to be polled at.
 
diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
index e87692c31be4..acd101caeeeb 100644
--- a/drivers/usb/host/uhci-hcd.c
+++ b/drivers/usb/host/uhci-hcd.c
@@ -60,6 +60,11 @@ Randy Dunlap, Georg Acher, Deti Fliegl, Thomas Sailer, Roman Weissgaerber, \
 Alan Stern"
 #define DRIVER_DESC "USB Universal Host Controller Interface driver"
 
+/* for flakey hardware, ignore overcurrent indicators */
+static int ignore_oc;
+module_param(ignore_oc, bool, S_IRUGO);
+MODULE_PARM_DESC(ignore_oc, "ignore hardware overcurrent indications");
+
 /*
  * debug = 0, no debugging messages
  * debug = 1, dump failed URBs except for stalls
@@ -169,6 +174,11 @@ static int resume_detect_interrupts_are_broken(struct uhci_hcd *uhci)
 {
         int port;
 
+        /* If we have to ignore overcurrent events then almost by definition
+         * we can't depend on resume-detect interrupts. */
+        if (ignore_oc)
+                return 1;
+
         switch (to_pci_dev(uhci_dev(uhci))->vendor) {
             default:
                 break;
@@ -921,7 +931,8 @@ static int __init uhci_hcd_init(void)
 {
         int retval = -ENOMEM;
 
-        printk(KERN_INFO DRIVER_DESC " " DRIVER_VERSION "\n");
+        printk(KERN_INFO DRIVER_DESC " " DRIVER_VERSION "%s\n",
+                        ignore_oc ? ", overcurrent ignored" : "");
 
         if (usb_disabled())
                 return -ENODEV;
diff --git a/drivers/usb/host/uhci-hub.c b/drivers/usb/host/uhci-hub.c
index f8347f1a10b6..bacc25c53ba3 100644
--- a/drivers/usb/host/uhci-hub.c
+++ b/drivers/usb/host/uhci-hub.c
@@ -52,10 +52,20 @@ static int any_ports_active(struct uhci_hcd *uhci)
 static inline int get_hub_status_data(struct uhci_hcd *uhci, char *buf)
 {
         int port;
+        int mask = RWC_BITS;
+
+        /* Some boards (both VIA and Intel apparently) report bogus
+         * overcurrent indications, causing massive log spam unless
+         * we completely ignore them.  This doesn't seem to be a problem
+         * with the chipset so much as with the way it is connected on
+         * the motherboard; if the overcurrent input is left to float
+         * then it may constantly register false positives. */
+        if (ignore_oc)
+                mask &= ~USBPORTSC_OCC;
 
         *buf = 0;
         for (port = 0; port < uhci->rh_numports; ++port) {
-                if ((inw(uhci->io_addr + USBPORTSC1 + port * 2) & RWC_BITS) ||
+                if ((inw(uhci->io_addr + USBPORTSC1 + port * 2) & mask) ||
                                 test_bit(port, &uhci->port_c_suspend))
                         *buf |= (1 << (port + 1));
         }
@@ -263,7 +273,7 @@ static int uhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
                         wPortChange |= USB_PORT_STAT_C_CONNECTION;
                 if (status & USBPORTSC_PEC)
                         wPortChange |= USB_PORT_STAT_C_ENABLE;
-                if (status & USBPORTSC_OCC)
+                if ((status & USBPORTSC_OCC) && !ignore_oc)
                         wPortChange |= USB_PORT_STAT_C_OVERCURRENT;
 
                 if (test_bit(port, &uhci->port_c_suspend)) {