# Lenovo Y570 Brightness



## BeautifulFish (Jul 5, 2012)

Hi,

I am using HEAD and I have a problem with the screen brightness, it is always at maximum. I am using the Intel driver in x11-drivers/xf86-video-intel.

/etc/make.conf

```
WITH_NEW_XORG
WITH_KMS
```

I tried the following with no result:

x11/xbrightness and x11/xcalib, they increase the black color, the screen maximum brightness is still on. Software illusion, not hardware.


```
#kldload acpi_ibm
#kldload acpi_video
```


```
#sysctl hw.acpi.video.lcd0.active=1
hw.acpi.video.lcd0.active: 0 -> 0
#sysctl hw.acpi.video.lcd0.brightness=30
hw.acpi.video.lcd0.brightness: 70 -> 30
```


```
#xbacklight -set 50
No outputs have backlight property
```

xorg.conf

```
Option "RegistryDwords" "EnableBrightnessControl=1"
```

Xorg.0.log

```
(WW) intel(0): Option "RegistryDwords" is not used"
```

Also xev doesn't detect Fn+Up/Down which should change the LCD brightness.


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## sim (Jul 6, 2012)

If I recall correctly I only needed to add 
	
	



```
Option "RegistryDwords" "EnableBrightnessControl=1"
```
 to xorg.conf. However my T510 is running on its nVidia adapter and the proprietary nvidia driver, so maybe that's the difference.

That's probably not very helpful, sorry!

sim


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## BeautifulFish (Jul 6, 2012)

Thanks Sim, unfortunately it doesn't work.. I wish I could use the nvidia driver but this laptop uses Optimus Technology "2 graphics cards". nvidia driver causes it to restart. And I can't disable the intel graphics card from the BIOS.


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## sim (Jul 6, 2012)

Interesting, mine also has the Optimus, but in my case it is possible to disable it in the BIOS.  Mine has two BIOS options - one appears to control whether the choice of device is delegated to the OS (fails), the other forces either the Intel or the nVidia option. If I don't force nVidia with the second option, I get the same symptoms you report.

sim


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## BeautifulFish (Jul 11, 2012)

mmm waiting for a bios update can take a while. 
Can this be helpful in any way? Maybe there is a way to control the level of the backlight brightness instead of just switching it on or off?


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## sim (Jan 20, 2013)

Gah! Just reinstalled on a replacement HD and now I can't get LCD brightness working again, despite checking the usual things (acpi_video, acpi_ibm, xorg.conf).

Ugly workaround - switch to the text console (Ctrl+Alt + F1) and you can use the brightness controls as normal, then switch back to the X console.  (Something to do when your Mac friends aren't looking...)

sim


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## BeautifulFish (Dec 7, 2013)

I am using 10.0-ALPHA5 now, and the LCD brightness is still hurting my eyes. Switching to the text console doesn't work for me with KMS.


```
# kldstat
 6    1 0xffffffff812fa000 7480     acpi_video.ko
 7    1 0xffffffff81302000 6be8     acpi_ibm.ko
 8    1 0xffffffff81309000 d28      acpi_call.ko

# sysctl -a | grep video
hw.acpi.reset_video: 1
hw.acpi.video.crt0.active: 0
hw.acpi.video.lcd0.active: 0
hw.acpi.video.lcd0.brightness: 17
hw.acpi.video.lcd0.fullpower: 17
hw.acpi.video.lcd0.economy: 10
hw.acpi.video.lcd0.levels: 70 30 10 17 23 30 40 50 60 70 80 90 100
hw.acpi.video.ext0.active: 0
dev.acpi_video.0.%desc: ACPI video extension
dev.acpi_video.0.%driver: acpi_video
dev.acpi_video.0.%parent: vgapci0
dev.acpi_video.1.%desc: ACPI video extension
dev.acpi_video.1.%driver: acpi_video
dev.acpi_video.1.%parent: vgapci1

# sysctl -a | grep ibm
#
```

I can't convert DSL to AML:

```
# iasl -tc 1.dsl

Intel ACPI Component Architecture
ASL Optimizing Compiler version 20130823-64
Copyright (c) 2000 - 2013 Intel Corporation

Compiler aborting due to parser-detected syntax error(s)
1.dsl     13353:         Package (0x06)
Error    6126 -             ^ syntax error

ASL Input:     1.dsl - 13373 lines, 423692 bytes, 5268 keywords
Hex Dump:      1.hex - 199 bytes

Compilation complete. 1 Errors, 0 Warnings, 0 Remarks, 0 Optimizations
```

1.dsl uploaded to ZeroBin. http://sebsauvage.net/paste/?d2df3b8bcd86e41f#7Jq9VWOe82Jp1KpdMxK9tJDTXavFzEU1YV2KGpqakg8=


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## CanOfBees (Dec 29, 2013)

Hi @BeautifulFish, 

I found sysutils/acpi_call helpful with screen brightness settings on a ThinkPad T430s. After loading the kernel module, I run the following e.g. `acpi_call -p '\VBRC' -i [i]N[/i]`, where _N_ is between 0-16.

I couldn't get `acpi_video` or `acpi_ibm` to work with this hardware. 

I hope this is helpful.

Cheers,
CoB


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## BeautifulFish (Jan 6, 2014)

Hi @CanOfBees,

Thanks for your reply.

Unfortunately it doesn't work:

```
#kldload acpi_call
#acpi_call -p '\VBRC' -i 5
Unknown object type '0'
```
Here is an old discussion about it: http://freebsd.1045724.n5.nabble.com/Lenovo-Y570-backlight-td5726207.html


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