fedora 7 - legacy USB?

[Mikkel L. Ellertson]

Claude Jones wrote:
> On Tuesday August 14 2007 4:03:31 pm Mikkel L. Ellertson wrote:
>> The keyboard controller is a chip on your motherboard that
>> handles communication between the computer and the keyboard.
>> It used to be a discrete chip, and would sometimes be included
>> in a BIOS update chip set. I would suspect that is is part of
>> a multi-function chip on most new motherboards.
> 
> I learned this the hard way, by hot-plugging an old atx keyboard 
> (is that what they called them? the ones with the big fat 
> cylindrical plug)

I believe they were called AT keyboard connectors, although the same
connector was used on the PC, XT, AT, 386, 486, and Pentium
machines. (At the same time, the PS/2 connector could be found on
some XT class and later machines...) Note that the PC and XP had a
different keyboard layout then the later machines.

> into the computer. After hours of 
> troubleshooting we figured out the keyboard IC was hosed - that 
> was 20 years ago, when we really had to try to fix things 
> because it was real expensive to replace them. I think you're 
> right, the keyboard is now controlled by a mutlifunction chip. 
> I'm suspecting that chip to be his problem - he says he's sure 
> he's plugged into the right PS/2 connector. That's a pretty dire 
> diagnosis, which is why I keep trying to think of things he 
> should try. 
> 
Well, with the keyboard failing in multiple OS's when used in other
then the default mode, I suspect that there is a hardware or
firmware problem that shown up when you try to change setting on the
keyboard controller. A software problem would not show up in both
Windows and Linux. A hardware or firmware problem would. Because the
problem stays with the computer, and not the keyboard, it points to
a motherboard problem.

There is a slim chance that it may be a power problem. Depending on
the motherboard, there may be a jumper to select where the keyboard
gets it power. There is an option to have the keyboard powered even
when the computer is suspended. You can use the keyboard to wake up
the system. On at least one of my systems it is called +5VSB and
requires that the power supply supply at least 1A on the +5VSB lead.
Now, if his keyboard is jumpered that way, and some of his USB
sockets are also jumpered that way, then there may not be enough
power then the USB devices are turned on. (My USB sockets also have
the option to be powered from this source, to let USB devices wake
up the system.) It is a long shot, but it is worth looking into. If
this is the case, then changing to a USB keyboard may not help if it
gets powered off the same supply.

Mikkel
-- 

  Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!

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