Is it possible to power off a PCIe video card/slot? (eg. hot-plug)

I'm looking at building a system that supports VT-d so I can pass through a high powered loud video card to a Xen/KVM/whatever VM (host will be Linux based). However, when I'm not using the VM I want to turn the video card off so its fan does not run. The card will not be used when the VM isn't running.

Anyone know if this is possible? The PCI-Express hot-plug specification allows cutting power to specific slots but I have never heard of anyone doing it with a video card and my searches for information have turned up nothing.

CR.

Posted 2012-07-05T19:55:28.153

Reputation: 261

https://superuser.com/questions/914810 has a better answer than this question here. Still not quite it, though. – Nobody – 2016-11-01T11:09:46.653

Answers

In theory the specification allows it; in practice your motherboard would have to expose the functionality to something application that would let you adjust this, and I have never seen nor heard of either.

Shinrai

Posted 2012-07-05T19:55:28.153

Reputation: 18 051

This can't be the complete set of possibilities. Besides the mentioned hot-plug specifications which remains to be investigated (also for http://superuser.com/questions/914810/how-to-disable-a-plugged-in-pci-e-graphic-card-on-os-level) it'd be possible to write a PCIe driver that checks whether the card is plugged or not for every processing cycle. That'd be very inefficient, but possible.

– Karl Richter – 2015-06-14T09:31:23.063