Arch Linux

imrehg

Member

From: London, UK

Registered: 2008-04-10

Posts: 108

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how to power-down and power-up USB devices in software? Asus ACPI hint

Hi!

I'm using Arch on Asus EeePC, and it works like a charm so far. I'd like to extend it with some hardware, like bluetooth and gps - hopefully built in (as others have done before).

Before building any USB modules inside, out of reach, I'd like to be able turn on/off the devices.

  I was wondering, what is the method to power on/off USB thingies in software? I know it can be done, because the Asus ACPI module for the EeePC does just that for the built in webcam and SD card reader.
The kernel module source can be downloaded from here: ftp://ftp.asus.com/pub/ASUS/EeePC/701/A … 071126.rar

   When I use this module, it has an entries  /proc/acpi/asus/camera and /proc/acpi/asus/cardr in which if i write 0, it removes the device (no longer listed in lsusb, and dmesg shows it has been disconnected) while writing 1 turns the device back on, as if I just plugged it in.

   The problem is, I don't know enough about the methods used in this module's source, to be able to figure out, how was this power-down and power-up been done... 
   
   If anyone is knowledgeable enough, could check the source and give me a hint? Or if there's any other way, that could be helpful too...

    Cheers,
            Greg