From 5f8364b7d63acdc2216ca0f7d0a8557c318479ea Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 5 Dec 2006 16:29:55 -0500 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- Documentation/kernel-parameters.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index ef69c75780b..25d29851710 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: , + 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. -- cgit v1.2.3-18-g5258