Re: Weird USB over-current messages in recent kernels...

From: Sergei Shtylyov
Date: Wed Jul 06 2011 - 11:40:17 EST


Hello.

Alan Stern wrote:

Seen during boot the last few days on my laptop:

running 3.0.0-rc4-mmotm0622:
Jul 2 13:08:37 turing-police kernel: [ 2.788108] hub 2-0:1.0: over-current condition on port 1
Jul 2 13:08:37 turing-police kernel: [ 2.990088] hub 2-0:1.0: over-current condition on port 2
Jul 2 13:08:37 turing-police kernel: [ 3.193073] hub 6-0:1.0: over-current condition on port 1
Jul 2 13:08:37 turing-police kernel: [ 3.395088] hub 6-0:1.0: over-current condition on port 2

running 3.0.0-rc5-mmotm0630:
Jul 5 09:43:36 turing-police kernel: [ 203.686082] hub 6-0:1.0: over-current condition on port 1
Jul 5 09:43:36 turing-police kernel: [ 203.969179] hub 6-0:1.0: over-current condition on port 2
Jul 5 09:43:36 turing-police kernel: [ 204.217077] hub 6-0:1.0: over-current condition on port 1

The problem? I don't see any devices that would *cause* the condition:

The device 5 and 6 on bus 1 are attached to the docking station, the Jul 2 boot
was undocked and those two devices weren't present. Nobody home on bus 2 or 6
at any time, as far as I can tell.

Any ideas?

That message was added recently, which may explain why you haven't seen it before.

Wasn't there a similar dev_err() message before that patch that added this message (the previous message was printed on any over-current signal change)?

For more debugging, please collect a usbmon log for bus 2 or bus 6 (see Documentation/usb/usbmon.txt). In fact, you might try doing this for an earlier kernel as well.

It may be that your host controllers claim that an over-current
condition exists when it really doesn't, or it may be that those ports
are wired incorrectly and really do have an over-current condition.

If it's EHCI driver, there's module option to suppress over-current checking, called 'ignore_oc'. It should help with bogus over-current signalling...

Alan Stern

WBR, Sergei
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