# sporadic usb-disconnects

## dermund

Hi,

On my Via Epia Mainboard I have sporadic USB-Disconnects showing up in /var/log/messages. These aren't following specific patterns. I just have tried one USB-Device so far: A huawei e220 umts usb modem.

After the device have disconnected - lsusb calls and calls to /proc/bus/usb are hanging and cannot be terminated. The huawei-modem should be ok - on a xubuntu box it runs flawless.

I would be interesting for me to know, how to kill processes with a "D" or "D+" flag in "ps aux".

The wvdial-call has got this flag and I cannot terminate it with "killall -9 wvdial".

I cannot post logs - sorry - I am not on this computer at the mo.

Did anyone have a similar behaviour. Please help - evertime this happens I have to restart the computer. argh.

Greetings

dermundLast edited by dermund on Sun Sep 02, 2007 12:32 pm; edited 2 times in total

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## JeliJami

see Killing processes in Linux

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## dermund

okay - so "D" means device wait - and thus such processes cannot be killed.

Leaves me back with the problem that I don't know how to avoid these "USB Disconnects" hmm. This situation suits a router-box like shit  :Wink: 

Thank you anyway for your hint.

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## dermund

Update:

After I tried with Kernels 2.6.22.? and 2.6.19.? I have now tried a 2.6.17.3 and it now seems to work. No more disconnects so far.

In the process table - on the two newer kernels - there was a "ksuspend" process although I haven't compiled it in the kernel or as a module. I have red about a similar problem with usb suspend on a different thread - only conerning storage devices. But maybe this is the point.

I don't know why there is such a deamon (ksuspend), I really haven't compiled it in. Altough the modem is no storage device - it registers as such - a udev rule manages to ignore the storage part though.

So I add "solved" to the title until anything bad happens.

If anyone has got a link to this problem please post it - relating to ksuspend and blocking/freezing/"device wait"/-states.

Thank you

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## dermund

Well all of a sudden the problem went back... I changed nothing big... I think...

Oh maan. Maybe my active usb-cable is the source of these errors.

Furthermore I am now having an error with let the machine stuck on boot, before he wants to check the ram. If I plug the external harddisk out of the usb-interface then the boot continues: Isn't it funny   :Mad: 

Help!

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## dermund

I've bought a pci-usb-controller card for 8 with a nec-chipset. Now things are working and settled. No more discons.

So I guess this might be a kernel driver bug concerning the via-chipset vt82xxxxx family. I've come to this through an other thread in an other forum relating to problems with this chipset. Here is the link:

http://www.linuxforums.org/forum/ubuntu-help/73617-usb-2-drive-freezes.html

cheers

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## tekknokrat

does this new usb chipset, you just use, has resume support?

dmesg tells me ( via vt82... on msi k8t opteron board ) that driver lacks resume.

kernelconfig:

CONFIG_PM=y

CONFIG_ACPI=y

 *Quote:*   

> 
> 
> usb 1-5.1: GSM modem (1-port) converter now attached to ttyUSB0
> 
> Device driver ttyUSB0 lacks bus and class support for being resumed.
> ...

 

Imo, suspend / resume is automaticly compiled in for other modules if you use powermanagement acpi features in kernel, please correct if I am wrong.

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