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#1 2013-02-26 15:39:56

LinuxCoyote
Member
Registered: 2012-04-21
Posts: 5

[SOLVED] Brightness Key Levels T430

I recently updated to Gnome 3.6.3.1, and my brightness key levels are limited.  I'm on a Thinkpad T430.  Using the FN keys, I used to be able to bring brightness to 100, as the max_brightness file describes.

 # cat /sys/class/backlight/acpi_video0/max_brightness  
100

when I bring my screen to full brightness with the FN keys now though:

# cat /sys/class/backlight/acpi_video0/brightness 
75

and when I bring it to minimum brightness:

# cat /sys/class/backlight/acpi_video0/brightness 
15

I can echo values into the brightness file in increments of 10, and change brightness that way, but I would like the function keys to work properly, as they did in previous versions of Gnome. What is causing this?

Last edited by LinuxCoyote (2013-03-22 04:56:13)


Thinkpad T430 Core i5 3320M IntelHD 4000
Samsung Q430-11 Core i5 450M Nvidia 310M
Raspberry Pi Model B (256M)

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#2 2013-03-10 19:26:35

mamuf
Member
From: CZ
Registered: 2013-03-10
Posts: 2

Re: [SOLVED] Brightness Key Levels T430

I have the exact same issue on my Thinkpad T530.


Dell Latitude E6400
Lenovo Thinkpad T530

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#3 2013-03-10 19:55:55

elkoraco
Member
Registered: 2013-02-18
Posts: 122

Re: [SOLVED] Brightness Key Levels T430

Try to boot with the acpi_backlight=vendor parameter.

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#4 2013-03-19 15:35:17

LinuxCoyote
Member
Registered: 2012-04-21
Posts: 5

Re: [SOLVED] Brightness Key Levels T430

Using the acpi_backlight=vendor parameter, I am able to use the keys to fully change brightness with the keys, however gnome OSD reports wrong levels, and I can't control brightness through gnome.  Minor annoyances.  I'll try rolling back to an earlier kernel later to see if the original problem lies with that.


Thinkpad T430 Core i5 3320M IntelHD 4000
Samsung Q430-11 Core i5 450M Nvidia 310M
Raspberry Pi Model B (256M)

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#5 2013-03-19 16:34:37

WonderWoofy
Member
From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

Re: [SOLVED] Brightness Key Levels T430

+1

I too noticed that lately my backlight keys have stopped working with the latest kernels (namely the 3.8.* ones).  I too have a ThinkPad, though mine is an E430.  At first I thought it might be because I had to have a new motherboard installed which came with a new bios version, but realized the the lts 3.4 kernel provided that functionality for me again.

I too was able to have this fixed by telling the system to prefer thinkpad_acpi for this control (using the acpi_backlight=vendor kernel command line parameter).


Edit: BTW, with this parameter, I now no longer have acpi0_backlight, but rather intel_backlight and thinkpad_screen.  Thinkpad_screen was set to 0, so when I echoed the highest value (seven) into the brightness file it went up, but I couldn't get it to go back down via writing to the file.  I haven't tried using intel_backlight, but would like to note that changing the brightness with the now functional hot keys produces no change in the /sys directories.  This might not be the best solution for anyone looking to script this functionality, or who wants to set a certain brightness on boot (using a tmpfiles.d conf file or a udev rule).

Last edited by WonderWoofy (2013-03-19 16:43:56)

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#6 2013-03-21 23:33:31

julian24
Member
From: Germany
Registered: 2011-08-05
Posts: 17

Re: [SOLVED] Brightness Key Levels T430

I pretty much had the same problem. Even though acpi_backlight=vendor somehow fixes this, using acpi_osi="!Windows 2012" instead seems to be a better idea.

For an explanaiton, see https://bbs.archlinux.org/viewtopic.php … 7#p1247507. There's also a post on the thinkpad_acpi mailing list that sounds like acpi_backlight=vendor really isn't a good solution: http://sourceforge.net/mailarchive/mess … d=30569078.

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#7 2013-03-22 04:05:36

WonderWoofy
Member
From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

Re: [SOLVED] Brightness Key Levels T430

julian24 wrote:

I pretty much had the same problem. Even though acpi_backlight=vendor somehow fixes this, using acpi_osi="!Windows 2012" instead seems to be a better idea.

For an explanaiton, see https://bbs.archlinux.org/viewtopic.php … 7#p1247507. There's also a post on the thinkpad_acpi mailing list that sounds like acpi_backlight=vendor really isn't a good solution: http://sourceforge.net/mailarchive/mess … d=30569078.

I noticed those thermal warnings as well, and can confirm that on my machine switching to acpi_osi="!Windows 2012" does indeed stop them from coming up.  Also it seems that with 3.8.4 this also makes the /sys/class/backlight/acpi_video0/brightness actually respond to and change the system brightness!  Horray!!

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#8 2013-03-22 04:52:43

LinuxCoyote
Member
Registered: 2012-04-21
Posts: 5

Re: [SOLVED] Brightness Key Levels T430

I changed by boot parameters to acpi_osi="!Windows 2012" and my thinkpad is now back to normal, yay!  Thanks, julian24 

acpi_backlight=vendor was not an ideal solution.  I had problems with the default brightness being really low coming back from sleep, along with the previous mention of the gnome OSD, and gnome control problems.  With the acp_osi parameter, everything is back to normal (OSD reports correct levels, gnome can control the backlight, and no problems with the keys).  I should also note though that I have not updated my firmware since I first got it (mid-summer 2012), and I am running the 3.8.3 kernel.


Thinkpad T430 Core i5 3320M IntelHD 4000
Samsung Q430-11 Core i5 450M Nvidia 310M
Raspberry Pi Model B (256M)

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#9 2013-03-22 11:38:00

julian24
Member
From: Germany
Registered: 2011-08-05
Posts: 17

Re: [SOLVED] Brightness Key Levels T430

LinuxCoyote wrote:

I should also note though that I have not updated my firmware since I first got it (mid-summer 2012), and I am running the 3.8.3 kernel.

Just out of curiosity: Which BIOS version do you have? Either

dmesg | grep DMI

or

dmidecode | grep "BIOS Rev"

should tell you.

To me it looks like there were changes in both the kernel and the firmware/BIOS. So for example if I boot linux-lts it works without that command line parameter but I'm relatively sure that I didn't upgrade firmware and kernel at the same time. But I'm too lazy to git-bisect the kernel.

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#10 2013-03-22 12:53:13

LinuxCoyote
Member
Registered: 2012-04-21
Posts: 5

Re: [SOLVED] Brightness Key Levels T430

$ dmesg | grep DMI
[    0.000000] DMI: LENOVO 2347UN9/2347UN9, BIOS G1ET90WW (2.50 ) 12/18/2012
[   10.939239] input: HDA Intel PCH HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:1b.0/sound/card0/input8
[   10.940241] input: HDA Intel PCH HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:1b.0/sound/card0/input9
[   10.940357] input: HDA Intel PCH HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:1b.0/sound/card0/input10

Thinkpad T430 Core i5 3320M IntelHD 4000
Samsung Q430-11 Core i5 450M Nvidia 310M
Raspberry Pi Model B (256M)

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#11 2013-03-23 01:33:26

tuxero
Member
Registered: 2013-03-14
Posts: 13

Re: [SOLVED] Brightness Key Levels T430

thanks, this solved my issue, too:
https://bbs.archlinux.org/viewtopic.php?id=159925

however, the " does not work in grub. acpi_osi='!Windows 2012' works

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#12 2013-03-25 09:53:37

mamuf
Member
From: CZ
Registered: 2013-03-10
Posts: 2

Re: [SOLVED] Brightness Key Levels T430

tuxero wrote:

however, the " does not work in grub. acpi_osi='!Windows 2012' works

You have to backslash the double quote in /etc/default/grub, then it works:

GRUB_CMDLINE_LINUX="acpi_osi=\"!Windows 2012\""

And thanks to all of you, this fixed this issue for me as well.


Dell Latitude E6400
Lenovo Thinkpad T530

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#13 2013-03-26 00:20:00

Fryguy
Member
Registered: 2008-04-15
Posts: 8

Re: [SOLVED] Brightness Key Levels T430

I tried doing acpi_osi="!Windows 2012" and this doesn't seem to work for me.  /sys/class/backlight/acpi_video0 exists, and brightness ranges from 0-15, but changing /sys/class/backlight/acpi_video0/brightness doesn't cause any change to the screen.

Adding acpi_backlight=vendor causes it to change to thinkpad_screen from acpi_video0, but changing the brightness here doesn't affect anything either.

Here's some relevant messages from my dmesg (this was captured with acpi_osi set and acpi_backlight not set):

[    1.949590] thinkpad_acpi: detected a 8-level brightness capable ThinkPad
[    1.950370] thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver
[    1.950371] thinkpad_acpi: Disabling thinkpad-acpi brightness events by default...
[    1.981253] thinkpad_acpi: Standard ACPI backlight interface available, not loading native one
[    2.247077] nouveau  [     DRM] ACPI backlight interface available, not registering our own


My laptop is a T530 with optimus graphics, and discrete graphics enabled (I frequently use a second monitor).

Any other ideas?

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#14 2013-06-30 17:20:45

acefruchtsaft
Member
Registered: 2012-03-02
Posts: 2

Re: [SOLVED] Brightness Key Levels T430

Alternatively, you could try acpi_osi="Windows 2009" (which corresponds to Windows 7) or even acpi_osi=linux.

On my T430, acpi_osi="!Windows 2012" does nothing (using kernel 3.9.8-1-ARCH), while the brightness control keys work somewhat with the former settings (changing brightness is not entirely smooth and the actual level does not always correspond to the one shown by KDE, but at least it works somewhat, while with acpi_osi="!Windows 2012" it does not work at all).

Maybe this depends on whether the discrete Nvidia GPU or Intel HD is used, I am currently using the former with proprietary Nvidia drivers.

Last edited by acefruchtsaft (2013-06-30 17:22:43)

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