Subject: Re: USB mouse dies
To: Harry Waddell <waddell@caravan.com>
From: Steven M. Bellovin <smb@cs.columbia.edu>
List: current-users
Date: 03/04/2005 14:18:57
In message <20050304111354.7e261336.waddell@caravan.com>, Harry Waddell writes:
>On Fri, 4 Mar 2005 11:50:35 -0500 (EST)
>Brad Spencer <brad@anduin.eldar.org> wrote:
>
>> 
>>    Two of my machines have USB mice.  On occasion, and without apparent 
>>    cause, the system will stop seeing any mouse events.  Usually, 
>>    unplugging the mouse and reconnecting it will solve the problem; 
>>    sometimes, though, I have to reboot.  Any suggestions on the cause (or 
>>    a fix)?  
>> 
>>    I'm running -current with xorg on new Dell Dimension 8400s, with ITAC 
>>    Systems Mouse-Traks.
>> 
>> 		   --Prof. Steven M. Bellovin, http://www.cs.columbia.edu/~smb
>> 
>> 
>> 
>> 
>> 
>> 
>> I see this all the time on my Toshiba notebook when there is large amounts
>> of LAN activity on the wi device.  Other ethernet devices do not seem to
>> trigger the problem as often, or at all.
>> 
>> 
>
>I've noticed that placing a mini-fridge on the same power strip as my notebook
>ac adapter causes the same thing to happen sometimes at exactly the moment 
>when the compressor cycles on. I think this has happened under windows a few
>times too, so perhaps it's really a hardware problem. I use optical mice, 
>which I believe use about 100mA of current from the bus, so combinations 
>of hardware and usb peripherals which use modest amounts of juice have similar
>problems. 
>
>This is just a hypothesis. I can't back it up, nor have I tested it. I can
>think of a few reasons why it shouldn't be true. I do know that since
>I've rearranged my power cables it happens much less freqeuntly than it used
>to.

Interesting.  I'm about to move one of the affected machines to a UPS; 
I'll see what happens.

		--Prof. Steven M. Bellovin, http://www.cs.columbia.edu/~smb