On Tue, 29 Apr 2008 11:16:24 -0700, martin.hofherr wrote:

> On Apr 29, 7:21Â*pm, "John F. Morse" <xanadu....@example.invalid> wrote:
>> martin.hofh...@googlemail.com wrote:
>> > There is another change in the mouse and keyboard story.... The
>> > biosupdate didn't help much, the mouse an keyboard froze again. But
>> > then I stumbeled
>> > eventually over this:
>> >https://bugs.launchpad.net/ubuntu/+bug/196902
>>
>> > And until now it worked fine. Since I plugged an usb-hub at the rear
>> > usb-slots an connected
>> > the mouse to the hub it didn' t freeze anymore. Let's see how long it
>> > lasts...
>>
>> Maybe I missed it, but I didn't see where they found any solution.
>>
>> USB is funny -- I have a PC with two ports in the rear, and two in the
>> front. The front ones work fine for a digital camera, but they won't
>> work for a thumb drive. It needs to be plugged into a rear port to
>> work.
>>
>> I'm curious if it might me some problem (or omission) with USB supplied
>> power, maybe not getting through, or provided by, an internal USB "hub"
>> that feeds the front connectors.
>>
>> I've always just worked around it, but may investigate it further some
>> day.
>>
>> That is something you might consider too: move your USB keyboard and
>> mouse to a USB port on the other end of the PC.
>>
>> Of course using a PS/2 or serial mouse for a test would determine if it
>> is the USB port(s) or something else.
>>
>> --
>> John
>>
>> No Microsoft, Apple, Intel, Trend Micro, nor Ford products were used in
>> the preparation or transmission of this message.
>>
>> The EULA sounds like it was written by a team of lawyers who want to
>> tell me what I can't do. The GPL sounds like it was written by a human
>> being, who wants me to know what I can do.
>
>> Maybe I missed it, but I didn't see where they found any solution.
> Sorry, I posted the wrong link. This is the right one:
> http://www.nvnews.net/vbulletin/showthread.php?t=82640 Sorry.
> Until now it works, but you never know.. I've had the same problems with
> digtial cameras too, only vice versa: Thumb drives
> where detected but the flash-card reader wasn't. I haven't tried yet, if
> it works now,
> after I installed Debian (before it was gentoo...) Maybe some module was
> missing in the
> kernel.
> Unfortunately I can't try a PS/2 or serial mouse, because the dimension
> c521 doesn't
> have neither a serial nor a PS/2 port. But I guess that it has something
> to do with the
> usb ports or the nvidia chipset.

There is a fundamental difference between front and rear usb2 ports on
most machines, if not all. The front ports often split the power
available, and they are often on an internal hub. The result is that many
devices that require high throughput will not run properly on front
ports. This often includes external hard drives and scanners and
sometimes printers.