My workstation has multiple video cards. One is a loud high power unit that I use for scientific visualization, CAD, gaming, etc and the other is a silent low power card. I'm looking for a way to power off the loud card when I'm not using it (which is 99% of the time because I'm mostly just writing software). Anyone know if this is possible and how to go about it?
I know there is a bunch of control stuff in /sys/devices/pciXXXX/. I tried "removing" the card from that interface and it worked (device became unavailable) but the card did not power off. I'm thinking I need to use one of the sleep states or something. From my reading I get hints that it's possible to cut power to specific PCI slots but I can't figure out exactly how. Any ideas?
Yeah but that wouldn't power down the card either. I want to turn it off so the fan doesn't run.
I played with some ACPI utilities and tried to put it in D3 sleep mode but it didn't do anything. I think there is some other interface specific to PCI (ie. not ACPI) that allows directly cutting power to specific PCI slots. I can't find much information on how to use it though.
According to the kernel documentation:
What: /sys/bus/pci/devices/.../remove Date: January 2009 Contact: Linux PCI developers <email@example.com> Description: Writing a non-zero value to this attribute will hot-remove the PCI device and any of its children. Depends on CONFIG_HOTPLUG.
Only thing is, I can't find any "remove" files at all under /sys/bus/pci/devices/. I don't know if I need another module loaded or what. I currently have pci_hotplug and pciehp loaded and CONFIG_HOTPLUG=y
Argh, I hate how there is practically no information on how to use this. I found some mention of not being able to hotplug video devices based on a misunderstanding of the PCI spec or something and they were suppose to enable it but then there were no more posts, no information, no nothing... That was 2 years ago... !!!
Last edited by oz (2012-06-09 13:00:41)
Finally, I found the "remove" files. They aren't under /sys/bus/devices/ but in a different path under each device.
Unfortunately removing it doesn't power off the card. Could be because my console is on that card but I can't figure out how to switch the console to another card. I give up.