usb keyboard attached to monitor usb out problem

[Davno]

Hi,
My usb keyboard was plugged at the back of my monitor on one of its usb port.
This set-up use to work nice for months, but now for no apparent reason it does not work anymore. The keyboard is recognise only when an OS start booting but not at the boot loader level anymore, so i can not choose the OS, its like it is not recognise fast enough. The strange thing is after the 10 seconds (default time for lilo) the OS boot and then the keyboard works.
As a temporary fix i connected the keyboard to another usb port on the back on my comp tower.
Any ideas why it does not work anymore. It is not bios related because it work when plugged in the back of the computer instead of the monitor.
P.S. No change where recently made on hardware or software side.

[Satanic Atheist]

Good question... no obvious reason why it should suddenly stop working which would therefore indicate hardware failing.

Is your BIOS set up to recognise a USB keyboard? I know you say it hasn't changed, but it might sort the problem. Strange that it'll work when it's directly attached but not through a hub...

Slightly off-topic, but still relevant - I've had trouble before with a PCMCIA USB 2.0 hub. Since USB runs at 5V but PCMCIA runs at 3.3V, unpowered devices (such as external 2.5" hard drives without a power adapter) cause the machine to lock up solid unless the extra power is supplied. This (on my card) is provided by a USB to power jack that plugs into the card and a native USB port on the computer. Powered devices (such as external hard drives with their own power supplies) do not seem to be affected.

James

[bwkaz]

Strange that it'll work when it's directly attached but not through a hub... Not necessarily completely strange: Your BIOS's boot-time USB "driver" may not have the smarts to handle hubs. Most of the BIOSes in use on machines at work don't.

If you plug the device directly into the computer, there's one hub between the USB host controller and the keyboard. If there's an extra monitor in there, then there's another hub in the way. (Of course, I assume the monitor is on, correct? Well, wait: it'd have to be, if you can see the bootloader. OK, never mind that then.) The BIOS may not have a full hub driver (actually it probably doesn't, since the BIOS needs to be fairly tiny), so it may only be able to handle the mini-hub on the motherboard itself.

I don't know why it suddenly changed, though. Unless there was a BIOS upgrade in there somewhere? Normally they wouldn't remove features, but maybe this is a bug or something.

[Davno]

Good question... no obvious reason why it should suddenly stop working which would therefore indicate hardware failing.
I just checked the bios and i see no change: USB devices enable: 1 keyboard, 1 mouse, 2 hubs.
But i recall that last week the power went off/on twice within a few second during a thunder storm before i could unplugged from the wall, may be there was some damage on the usb outlet of the monitor. I have a surge bar but its a cheap one.
Anyway i connect it to the back of the computer and it is working ok, its no big deal, it was just practical (no wire in the way) to have it connected on the back of the monitor.
Thanks guys.

[Satanic Atheist]

If you are using a surge protector then I'd be surprised if it allowed a high enough current through to physically damage something. And the USB hub in the monitor would be the last thing to go (it's largely isolated by the other circuitry) - you'd have other problems as well. Now, since the thing works once Linux has started up, it's even less likely that you've suffered damage somewhere.

It's still strange that it was working before and whilst bwkaz's idea is perfectly reasonable, it still doesn't explain why it worked before but not now.

Oh well, I'm out of ideas. All I can really think of is that there's something failing in there somewhere...

Sorry I can't help any more.

James