Messages in this thread | | | Date | Fri, 3 Oct 2008 14:40:24 -0400 (EDT) | From | Alan Stern <> | Subject | Re: USB disconnects every 30 seconds (2.6.27-rc8) |
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On Fri, 3 Oct 2008, Dave Hansen wrote:
> I'm seeing some odd USB behavior with newer kernels > (2.6.27-rc8-00062-g330f647 to be exact). Almost exactly, every 30 > seconds, one of my USB hubs disconnects.
Actually two of the hubs disconnect: 3-4.1 and 3-4.4.4. Neither is beneath the other.
> At first, I thought it was a > hardware issue, and started swapping cables. Then, I realized that I'd > *just* rebooted into a new kernel. So, I booted back to the distro > kernel and these went away. > > Even though my mouse is hanging off that hub,
No it isn't. The mouse is 3-4.4.1, which is not below either 3-4.1 or 3-4.4.4.
> I don't seem to notice the > disconnects. > > $ dmesg | grep disconnect > [ 3599.496217] usb 3-4.4.4: USB disconnect, address 122 > [ 3599.677346] usb 3-4.1: USB disconnect, address 121 > [ 3627.804621] usb 3-4.1: USB disconnect, address 124 > [ 3628.004400] usb 3-4.4.4: USB disconnect, address 123 > [ 3659.496421] usb 3-4.4.4: USB disconnect, address 126 > [ 3659.676186] usb 3-4.1: USB disconnect, address 125 > [ 3689.493763] usb 3-4.1: USB disconnect, address 3 > [ 3689.708916] usb 3-4.4.4: USB disconnect, address 127 > [ 3719.497221] usb 3-4.4.4: USB disconnect, address 7 > [ 3719.684965] usb 3-4.1: USB disconnect, address 6 > [ 3749.496323] usb 3-4.1: USB disconnect, address 9 > [ 3749.691180] usb 3-4.4.4: USB disconnect, address 8 > > Full dmesg and .config: > > http://sr71.net/~dave/linux/config-10-03-2008.1.txt > http://sr71.net/~dave/linux/dmesg-10-03-2008.1.log > > The last one I tried before this was -rc3, and it appears to be OK. The > Ubuntu 2.6.24-19-generic kernel also appears not to have this issue. > > A quick scan of LKML and linux-usb didn't turn up anything similar. > > The machine is a Lenovo T61 plugged into the Lenovo dock. At this > point, the only thing plugged into the suspect hub is my mouse.
In fact, nothing is plugged into either of the hubs.
In theory this could be caused by a problem in the dock. But it would be better to get more information before trying to pin down the cause.
You should use usbmon (see Documentation/usb/usbmon.txt) to record a trace of everything happening on bus 3. And to keep things simple, you should unplug all the USB devices except for one of the magical disappearing hubs.
Alan Stern
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