<p dir="ltr">Well keep us updated.</p>
<div class="gmail_quote">On May 10, 2016 4:29 PM, "Todor Fassl" <<a href="mailto:fassl.tod@gmail.com">fassl.tod@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">[Sorry to top post but I am blind and it is very difficult for me to post in-line.]<br>
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These workstations are in a lab and students are plugging usb devices into them all the time. I was checking the logs on one machine last week and I saw that somebody had plugged a web cam in. I am guessing it was for skype and/or linphone. I will never be able to pin it down to a specific usb device.<br>
<br>
But every time a machine is hung, it is always that same file, /sys/bus/usb/devices/usb1/descriptors, that causes it to go into an uninterruptable sleep. So I think the defective usb device is the usb controller itself.<br>
<br>
Well, I set the kernel parameter to disable usb autosuspend. I'll post back if it works. I did manage to write a script to notifiy me when the problem occurs so if the script doesn't trigger in a couple of days, I'm going to say it's fixed.<br>
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On 05/10/2016 10:16 AM, Phil Turmel wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On 05/10/2016 10:39 AM, Todor Fassl wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Details: I have 15 Dell workstations running ubuntu 15.10 (2 are running<br>
16.04 -- that did not help). Occasionally, the keyboard and mouse<br>
freeze. Logging in remotely and running lsusb hangs such that you can't<br>
even control-c outand it cannot be killed even with a -9. The process<br>
goes into an uninterruptable sleep during a system call to open the file<br>
/sys/bus/usb/devices/usb1/descriptors. That file is part of the kernel's<br>
control files for the usb controller itself. So you can see why the<br>
keyboard and mouse are dead, the driver for the usb controller itself is<br>
hung.<br>
</blockquote>
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<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
PS: I wouldn't mind ideas wrt the original problem either. Not that I<br>
hold out any hope for that.<br>
</blockquote>
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Ah, you have buggy USB devices. I've run into this. I used the kernel<br>
boot parameter usbcore.autosuspend=-1 to globally disable USB per-device<br>
power saving on my mythtv server. If you can narrow it down to a<br>
specific set of devices, you could create udev rules to prevent just<br>
those from sleeping.<br>
<br>
Some links:<br>
<br>
<a href="http://unix.stackexchange.com/questions/91027/how-to-disable-usb-autosuspend-on-kernel-3-7-10-or-above" rel="noreferrer" target="_blank">http://unix.stackexchange.com/questions/91027/how-to-disable-usb-autosuspend-on-kernel-3-7-10-or-above</a><br>
<br>
<a href="http://askubuntu.com/questions/80638/how-to-disable-auto-power-off-of-usb-devices-like-usb-mouse" rel="noreferrer" target="_blank">http://askubuntu.com/questions/80638/how-to-disable-auto-power-off-of-usb-devices-like-usb-mouse</a><br>
<br>
Phil<br>
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</blockquote>
<br>
-- <br>
Todd<br>
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</blockquote></div>