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Hallo,
i have an Asus UX32VD Laptop running ArchLinux.
Everything works fine after some tuning, but i have a high power usage of the Display backligt reported in powertop.
PowerTOP 2.1 Overview Idle stats Frequency stats Device stats Tunables
The battery reports a discharge rate of 14.4 W
System baseline power is estimated at 4.59 W
Power est. Usage Device name
3.08 W 100.0% Display backlight
1.57 W 0.0 pkts/s Network interface: wlan0 (iwlwifi)
1.57 W 60.0% Display backlight
1.57 W 41.9% Display backlight
658 mW 56.1 ops/s GPU
556 mW 100.0% Radio device: iwlwifi
307 mW 11.2% CPU use
0 mW 100.0% Radio device: asus-nb-wmi
0 mW 0.0% USB device: USB2.0 HD UVC WebCam (Chicony Electronics Co.,Ltd.)
0 mW 0.0% USB device: EHCI Host Controller
0 mW 0.0% USB device: xHCI Host Controller
0 mW 0.0% USB device: xHCI Host Controller
0 mW 0.0% USB device: USB2.0-CRW (Generic)
0 mW 0.0% Radio device: asus-nb-wmi
0 mW 0.0% USB device: usb-device-8087-0024
0 mW 0.0% USB device: usb-device-8087-0024
0 mW 0.0% USB device: EHCI Host Controller
0 mW 0.0% Audio codec hwC0D0: Realtek
0 mW 0.0% Audio codec hwC0D3: Intel
100.0% PCI Device: Intel Corporation 3rd Gen Core processor Graphics Controller
100.0% PCI Device: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1
100.0% PCI Device: NVIDIA Corporation Device 1140
100.0% PCI Device: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port
100.0% PCI Device: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode]
100.0% PCI Device: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 2
100.0% PCI Device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller
100.0% PCI Device: Intel Corporation HM76 Express Chipset LPC Controller
100.0% PCI Device: Intel Corporation Centrino Advanced-N 6235
0.0% PCI Device: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2
0.0% PCI Device: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1
0.0% PCI Device: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller
0.0% PCI Device: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1
0.0% PCI Device: Intel Corporation 3rd Gen Core Processor Thermal Subsystem
0.0% PCI Device: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller
If i change the brightness of the display the power usage stays the same.
Does anybody have an idea whats wrong with it?
Johannes
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Just to make sure, you are aware that powertop updates itself in intervals of maybe 10-15 seconds (not sure exactly), so after you change it, you should make sure that you refresh powertop.
Also I think that this could happen if you are using some kind of software brightness adjustment rather than something that actually changes the brightness through the /sys interface. How does your system handle brightness adjustment? Did you have to set it up? Hot keys? Muffins? Fairies?
In other words, is there. a module that handles the brightness keys, or are you changing the brightness through some application included with a DE?
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I use the Fn Keys to change the brightness and it seems that this changes the /sys/class/backlight/intel_backlight/actual_brightness file, so this should be ok.
I tested it again and with lowest brightness i get this result:
3.17 W 100.0% Display backlight
3.17 W 100.0% Display backlight
1.57 W 0.2% Display backlight
and with highest setting:
3.15 W 100.0% Display backlight
3.15 W 100.0% Display backlight
3.15 W 100.0% Display backlight
This seems quite high... And i don't understand why display backlight is listed three times..
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I've fixed this by adding some kernel parameters. It works perfectly under gnome (both gnome-control-center -> power and https://aur.archlinux.org/packages/gnom … -pulbs-git ) Fn keys (F5 & F6) are not working yet.
Bios :
$ sudo dmidecode -s bios-version
UX32VD.212
Kernel :
$ uname -a
Linux aega 3.9.4-1-ARCH #1 SMP PREEMPT Sat May 25 16:14:55 CEST 2013 x86_64 GNU/Linux
I am using grub-efi-x86_64 as UEFI bootloader. Unfortunately I don't know how to set kernel parameters for other bootloaders. You may find different bootloaders' settings in the wiki.
change line in /etc/defaults/grub :
GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_osi='!Windows 2012' acpi_osi=Linux add_efi_memmap i915.i915_enable_rc6=1 pcie_aspm=force drm.vblankoffdelay=1 i915.semaphores=1 nmi_watchdog=0 acpi_backlight=vendor"
acpi_osi='!Windows 2012' acpi_osi=Linux order is important!
Finally generate grub configuration file via grub-mkconfig.
sudo grub-mkconfig -o /boot/efi/EFI/grub/grub.cfg
And reboot.
Results :
$ cat /sys/class/backlight/intel_backlight/actual_brightness
421
PowerTOP 2.3 Overview Idle stats Frequency stats Device stats Tunables
The battery reports a discharge rate of 7.55 W
System baseline power is estimated at 4.00 W
Power est. Usage Device name
4.11 W 10.7% CPU use
988 mW 100.0% Radio device: iwlwifi
313 mW 9.8% Display backlight
162 mW 0.0% Display backlight
67.4 mW 22.5 ops/s GPU
58.3 mW 0.6 pkts/s Network interface: wlp3s0 (iwlwifi)
$ cat /sys/class/backlight/intel_backlight/actual_brightness
4302
PowerTOP 2.3 Overview Idle stats Frequency stats Device stats Tunables
The battery reports a discharge rate of 12.0 W
System baseline power is estimated at 4.00 W
Power est. Usage Device name
4.52 W 11.1% CPU use
2.31 W 100.0% Display backlight
2.31 W 100.0% Display backlight
1.06 W 100.0% Radio device: iwlwifi
322 mW 101.2 ops/s GPU
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