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authorAlan Stern <stern@rowland.harvard.edu>2006-12-05 22:29:55 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2006-12-20 19:14:26 +0100
commit5f8364b7d63acdc2216ca0f7d0a8557c318479ea (patch)
tree01f4c0bf84d46659772a623dd591bba7e1f2b635 /drivers/usb/host/uhci-hcd.c
parentUSB: Nokia E70 is an unusual device (diff)
downloadlinux-5f8364b7d63acdc2216ca0f7d0a8557c318479ea.tar.xz
linux-5f8364b7d63acdc2216ca0f7d0a8557c318479ea.zip
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-hcd.c')
-rw-r--r--drivers/usb/host/uhci-hcd.c13
1 files changed, 12 insertions, 1 deletions
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;