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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 13:14:26 -0500
commit5f8364b7d63acdc2216ca0f7d0a8557c318479ea (patch)
tree01f4c0bf84d46659772a623dd591bba7e1f2b635 /Documentation
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 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt8
1 files changed, 8 insertions, 0 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
1714 uart6850= [HW,OSS] 1714 uart6850= [HW,OSS]
1715 Format: <io>,<irq> 1715 Format: <io>,<irq>
1716 1716
1717 uhci-hcd.ignore_oc=
1718 [USB] Ignore overcurrent events (default N).
1719 Some badly-designed motherboards generate lots of
1720 bogus events, for ports that aren't wired to
1721 anything. Set this parameter to avoid log spamming.
1722 Note that genuine overcurrent events won't be
1723 reported either.
1724
1717 usbhid.mousepoll= 1725 usbhid.mousepoll=
1718 [USBHID] The interval which mice are to be polled at. 1726 [USBHID] The interval which mice are to be polled at.
1719 1727