usb keyboard aargh!
Mikkel L. Ellertson
mikkel at infinity-ltd.com
Sun Aug 20 15:02:33 UTC 2006
Claude Jones wrote:
> On Sunday August 20 2006 8:33 am, Tom Horsley wrote:
>> The motherboard BIOS never seems to have a problem seeing the
>> keyboard via the hub so something about the linux usb
>> bootstrapping must have some kind of timing problem.
>> Grrr....
>
> My day job is to manage about 50 Windows machines in a software company. Don't
> think that it's a Linux-only problem. I've wasted a lot of time on this
> particular problem. There's not much rhyme or reason to it - sometimes USB
> works, and sometimes it doesn't, in many different scenarios, not just the
> one you're describing. I've gone through many different theories, but I don't
> have a definitive answer - the protocol is imperfect, the manufacturers have
> imperfectly implemented it - those are the two I tend to suspect now. If the
> powered hub didn't fix it, I'd say you're going to have to live with it, or
> go with a PS2 solution. I keep several PS2 keyboards around our facility for
> this very reason. Things are improving, and USB has gotten a lot better, but
> I still encounter the occasional problem on new equipment.
>
> That's been my experience - I hope someone comes up with a definitive solution
> and proves me wrong.
To make things more interesting, sometimes the problem is a USB 1.1
device on a USB 2.0 controller. I can't remember the devices off
hand, but I have run into a couple of USB devices that said they
would work at 2.0 speeds when they really couldn't. They would work
fine when hooked to a USB 1.1 controller or hub, but not when hooked
to a 2.0 controller or hub. There are also some devices that will
not work correctly with some hubs. But using a different hub solves
the problem. It all depends on how well the specs are follower, I
guess. At times, I think it is just how the different manufacturers
shortcuts work together.
Mikkel
--
Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!
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