Using Debian with:
Linux mainLaptop 2.6.16-1-686 #1 Wed Mar 22 15:36:02 UTC 2006 i686 GNU/Linux

My laptop has 3 USB ports, 1 of which is attached to a cooler similar to what you might find here (url filtered cuz I'm a noob here). My particular fan isn't shown there, but that gives you the general idea.

lsusb:

... other stuff connected to the hub
Bus 001 Device 003: ID 046d:c506 Logitech, Inc. MX-700 Cordless Mouse Receiver
Bus 001 Device 002: ID 0451:2046 Texas Instruments, Inc. TUSB2046 Hub
Bus 001 Device 001: ID 0000:0000


The cooler is plugged into Bus 1 Dev 1. The cooler does nothing but draw power through the USB port to spin the fans. Now my question:

Is there any way to specifically shut off power to that particular USB port? Why: I'd like to run a script that polls the temperature of the

CPU and will only enable power for that port at or above a certain temperature. Since I'm not always physically present at this computer (it has become a desktop/server due to an old battery), just unplugging the cooler is not an option.


Can this be done programmaticly?

Doubt if that can be done unless hardware capiable. Best way is to find a device that control external devices. A type of Input/Output controller that can turn devices on and off from the PC either through the USB, Serial, or parallel port. Many of those devices contain examples of scripts to control the I/O ports. A simply script that keeps checking the cpu heat either from data from lm sensors or from a temperture probe attached to the I/O controller and then letting it turn the fan on when it is hot enough and off when it reaches the low temp setting you desire. I have devices like this but have never tried them or can remember where I have seen them. Others here when they read will know where to find what you are after. If I remeber I will post.

Edit:
It might be posiable for lm sensors to see the cpu temp and control the fan depending on the chipset. See what is under your /proc/acpi/fan. What is there if anything. From this depnding on the fan connector used for the cpu it might be able to control the remote fan as well. Some boards have more than one fan connector and can control all of them.
Edit:

Brian1