# Extreme power savings.  How do I power down PCI devices?

## DingbatCA

Building up a simple NAS and going for maximum power savings.  I have done the basics, like disk spin down and CPU governor. 

Running an Intel(R) Core(TM) i5-2510E with 4GB of DDR3L. 4.9 LTS kernel. New CPU is in the mail, Intel Celeron Dual Core Processor 1005M, which will also help.

Turns out the BIOS supports console redirect, so I am now running all console over a serial cable.  Any clues on how to power off/suspend PCI devices that I dont want running.  Currently looking to shutdown the Intel HD 3000 graphics.  Or at least put it into a suspended, our low power state.  I have a few other devices to go after like USB and audio, but I doubt they draw any where near as much power as the GPU.

lspci

```
00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)

00:01.0 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09)

00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)

00:06.0 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09)

00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)

00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (rev 05)

00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 05)

00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05)

00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5)

00:1c.6 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 7 (rev b5)

00:1c.7 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 8 (rev b5)

00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 05)

00:1f.0 ISA bridge: Intel Corporation QM67 Express Chipset Family LPC Controller (rev 05)

00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller (rev 05)

00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 05)

01:00.0 SATA controller: Marvell Technology Group Ltd. Device 9215 (rev 11)

04:00.0 Ethernet controller: Intel Corporation 82583V Gigabit Network Connection

05:00.0 USB controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 03)
```

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## josephg

modinfo the device and check various options. i have turned on all power saving options, even those tainting kernel. so far so good.

also try powertop.

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## DingbatCA

Can you post the tweaks you are using?

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## Ant P.

The kernel has a config option (under Bus Options) to default to powersaving mode, 4.11 added a second option to enable even more, you should have one of those turned on here.

Usually if a device has no driver loaded Linux will try to power it off automatically.

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