[LAU] usb midi keyboard not working when laptop on battery

[Jeremy Jongepier]

On 10/23/2012 08:29 PM, Atte André Jensen wrote:
> Hi
>
> I recently reverted from arch to ubuntu, and somewhere in that process
> my laptop stopped working with my usb keyboards (I have four, I didn't
> try all combinations, though) when my laptop is on battery.
>
> I never experienced this before, seems very strange to me. I might have
> been tinkering with some settings in the BIOS, not sure if they could
> have an impact on this.
>
> I don't have much info, heres what I have:
>
> 1) Keyboards work just fine on AC power
>
> 2) When laptop is running on battery, the keyboards show up in qjackctl
> just fine. I can connect to gmidimonitor, and I get "connected" in the
> gmidimonitor window. However no notes are shown in the gmidimonitor
> window. Sometimes playing notes on the midikeyboard will crash qjackctl.
>
> So I'm basically posting this here, hoping someone recognizes this
> behaviour or has an idea how to get closer to a solution.
>
> Thanks in advance for any input!
>

Hello Atte,

How old is your laptop? Maybe you're battery does not provide enough 
power anymore to power 4 USB keyboards. Batteries loose power throughout 
the years. So it could be that it has nothing to do with Ubuntu.
Just a wild guess though.

Best,

Jeremy