USB Ports - Power Available? Switching? (Odd question)

[lrmulli]

Odd question and even odder place to ask it!

Does anybody know what power the usb plugs on the PRO are capable of outputting?

I'm aware standard usb is 500ma but I was wondering whether it had been beefed up to support usb hard disks.

My second question - Is it possible to control the power to a usb port over say ssh?

The reason I ask these questions is I am currently powering my Raspberry Pi over the USB port of the PRO and it appears to be working fine but I wanted to know if it was only 500ma so if I run into further problems later down the line I know that power could be the cause. I also want to remote power on & off the Pi.


Many Thanks

Louis

[icewewe]

Louis,

The USB spec calls for 500mA/port maximum, although most vendors have been exceeding this for USB hard drives since forever.

I myself have a USB hard drive plugged in through one USB cable, so the port is definitely capable of handling more than 500mA for spin up, but I can't vouch for that being sustained as the hard drive I have is rated for 500mA draw.

As for shutting off the USB ports, I know it is possible (Windows will do it if there's a "Malfunctioning USB device" on the port) however I'm not aware of any facilities in linux, or specifically within the PLX kernel we're using that allows for that functionality.

Best of luck with your Pi! I'm jealous.

[WarheadsSE]

Windows doesn't always have the ability to power off the port, and simply ignores the port. I have no known methodology other than turning all USB on or off.

[lrmulli]

Thanks for the responses - I just went ahead and tried it.

It seemed to be running away fine with 1 usb hdd & my raspberry pi.

As soon as I added a 2nd drive I had random problems - random reboots on the Pi and general instability. So for now I have gone for a seperate power supply for the PI.

Thanks

Louis