I was given a MacBook Pro 2009 laptop where the screen does not work anymore. I suspect it's not the screen itself but the connection to the motherboard which is broken, since it's the hinge which got the shock and has visible damage.
Anyway I am setting this up as a home server, currently running a VPN server and with more plans for future.
And I want to decrease as much as possible the idle consumption, since the machine is going to be up near 100% of the year, and also to reduce the noise it makes (it's located on the desk where I work).
I have tried tlp (works well) and I'm now going more manually by running commands in /etc/rc.local to enable power saving settings. In both case I hit a plateau where I cant reduce the consumption below 17-18W (which is a lot compared to nowadays machines), with this strange result : here are the first few lines of powertop
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The battery reports a discharge rate of 17.4 W The power consumed was 342 J The estimated remaining time is 2 hours, 17 minutes Summary: 283.7 wakeups/second, 0.0 GPU ops/seconds, 0.0 VFS ops/sec and 1.6% CPU use Power est. Usage Events/s Category Description 11.5 W 0.0% Device Display backlight 4.77 W 2.0 pkts/s Device Network interface: enp0s10 (forcedeth) 1.31 W 0.0 pkts/s Device Network interface: wlp4s0 (wl) 1.07 W 0.0 pkts/s Device nic:tun0
So the display backlight consumes a lot of power, even though the screen doesnt work, the lid is closed, and I have set the brightness to zero (with
echo 0 > /sys/class/backlight/gmux_backlight/brightness, and the brightness does appear with usage 0% in the "Device stats" tab of powertop). How can I cut this down ?
If I could cut down 10W of consumption, that would be fantastic.
More minor : the wireless wlp4s0 also consumes power, but I have no use to it since the laptop is connected by ethernet. I have set it's power management (in powertop the line "Runtime PM for PCI Device Broadcom Limited BCM4322 802.11a/b/g/n Wireless LAN Controller" is good), and shut it off with
sudo ifconfig wlp4s0 down, but the powertop line remains the same around 1W. If anybody knows how to cut this down, that would also be a significant saving.