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authorAlan Stern <stern@rowland.harvard.edu>2006-12-05 16:29:55 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2006-12-20 10:14:26 -0800
commit5f8364b7d63acdc2216ca0f7d0a8557c318479ea (patch)
tree01f4c0bf84d46659772a623dd591bba7e1f2b635 /drivers/usb/host/uhci-hub.c
parentfe1ec341df1b510e5e614ccdad4a89273d6f6fe8 (diff)
UHCI: module parameter to ignore overcurrent changes
Certain boards seem to like to issue false overcurrent notifications, for example on ports that don't have anything connected to them. This looks like a hardware error, at the level of noise to those ports' overcurrent input signals (or non-debounced VBUS comparators). This surfaces to users as truly massive amounts of syslog spam from khubd (which is appropriate for real hardware problems, except for the volume from multiple ports). Using this new "ignore_oc" flag helps such systems work more sanely, by preventing such indications from getting to khubd (and spamming syslog). The downside is of course that true overcurrent errors will be masked; they'll appear as spontaneous disconnects, without the diagnostics that will let users troubleshoot issues like short-circuited cables. In addition, controllers with no devices attached will be forced to poll for new devices rather than relying on interrupts, since each overcurrent event would generate a new interrupt. This patch (as826) is essentially a copy of David Brownell's ignore_oc patch for ehci-hcd, ported to uhci-hcd. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host/uhci-hub.c')
-rw-r--r--drivers/usb/host/uhci-hub.c14
1 files changed, 12 insertions, 2 deletions
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)) {