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BBswitch is apparently dead with the last commit being 5 years ago and it no longer works with more modern kernels. During shutdown, it just hangs the system. Nouveau doesn't support power management on my GPU either.

I'd like to know what others are using who are in my situation as I don't need the nVidia GPU just running for no reason and would rather power it off when I'm on battery.

Jeff Schaller
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133794m3r
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  • https://www.youtube.com/watch?v=lKasS7DWn0s – ron Jun 19 '19 at 17:55
  • that youtube video suggests modifying grub with GRUB_CMDLINE_LINUX=" acpi_osi=! acpi_osi=\\\"Windows 2009\\\"" however I believe the best way to fully power down a GPU on pcie is to use **acpi_call**. I am interested in this as well, but this is as far as i've gotten on the matter. – ron Jun 19 '19 at 18:04

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With the nouveau driver, "power management" can mean several things.

On modern kernels, the nouveau driver knows how to access the same ACPI interface as bbswitch does, and will present it using the vgaswitcheroo mechanism, as /sys/kernel/debug/vgaswitcheroo/switch if you have the debugfs virtual filesystem mounted. This is essentially a solved problem: if you use the nouveau driver, you should no longer need bbswitch, period.

What the nouveau project usually means when talking about power management these days is monitoring the temperature of the GPU and adjusting its performance levels (clock speeds) dynamically. This is entirely separate from the power-off mechanism provided with vgaswitcheroo.

telcoM
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  • Here's a link to the page https://nouveau.freedesktop.org/wiki/PowerManagement/ and I have the NV160 it says "TODO" for everything under it. And vgaswitcharoo is apparently mainly made for hardware muxed devices. If it works with modern systems I'll try to use it. – 133794m3r Jun 19 '19 at 18:21