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Splooshie123 n00b
Joined: 16 Apr 2012 Posts: 27
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Posted: Fri Apr 20, 2012 10:43 am Post subject: Can't control brightness of MacBook Pro 6,2 LCD screen |
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Hi.
When I was using Ubuntu, I installed pommed to control the LCD brightness and keyboard backlight and eject key, etc.
In Gentoo, I discovered the ebuild for pommed is horribly outdated so I built pommed from source.
Pommed can successfully change my keyboard backlight and I was able to reverse the function key with it also.
However, I am still unable to change the brightness of the screen.
This is not a problem with pommed. I emerged nvclock and it is also unable to change the brightness.
After that, I emerged macbook-backlight and it is also useless: Code: | macbook-backlight -s 100
error, cannot find video card |
I know that all three programs access some files in /sys (or was it proc?) to change the brightness but the files don't exist. There is nothing related to the lcd backlight in /sys. The only thing I could find was "kbd_backlight" which is for the keyboard backlight. Any ideas why the relevant files are missing?
According to lspci, I have 2 GPUs: intel HD and NVIDIA GeForce GT 330M.
I am using the nouveau driver. |
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avx Advocate
Joined: 21 Jun 2004 Posts: 2152
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Posted: Fri Apr 20, 2012 12:12 pm Post subject: |
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Do you have FB_NVIDIA_BACKLIGHT set in your kernel? _________________ ++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>. |
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Splooshie123 n00b
Joined: 16 Apr 2012 Posts: 27
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Posted: Fri Apr 20, 2012 3:49 pm Post subject: |
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FB_NVIDIA_BACKLIGHT is not listed in my .config at all.
grep BACKLIGHT /usr/src/linux/.config
Code: | CONFIG_FB_BACKLIGHT=y
CONFIG_BACKLIGHT_LCD_SUPPORT=y
CONFIG_BACKLIGHT_CLASS_DEVICE=y
CONFIG_BACKLIGHT_GENERIC=y
# CONFIG_BACKLIGHT_PROGEAR is not set
CONFIG_BACKLIGHT_APPLE=y
# CONFIG_BACKLIGHT_SAHARA is not set
# CONFIG_BACKLIGHT_ADP8860 is not set
# CONFIG_BACKLIGHT_ADP8870 is not set
# CONFIG_LEDS_TRIGGER_BACKLIGHT is not set
CONFIG_DRM_NOUVEAU_BACKLIGHT=y |
EDIT: I just took a look at the config for Ubuntu (pommed worked there before) and discovered it had several more BACKLIGHT options, including CONFIG_FB_NVIDIA_BACKLIGHT.
Additionally, I discovered that CONFIG_FB_NVIDIA_BACKLIGHT is hidden in "make menuconfig" unless nvidia framebuffer support is activated.
I'm recompiling the kernel as I speak..........type, I'm recompiling the kernel as I type. |
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Splooshie123 n00b
Joined: 16 Apr 2012 Posts: 27
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Posted: Fri Apr 20, 2012 4:07 pm Post subject: |
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Setting CONFIG_FB_NVIDIA_BACKLIGHT didn't help. Or is there something else I need to do? |
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Splooshie123 n00b
Joined: 16 Apr 2012 Posts: 27
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Posted: Tue Nov 06, 2012 11:09 am Post subject: |
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Sorry to necro my own thread, but I finally found a solution 7 months later.
The backlight can be changed by echoing a brightness value to the Apple GMUX backlight driver.
Code: | echo 10000 > /sys/class/backlight/gmux_backlight/brightness |
Pommed doesn't support this particular driver, but it was trivial to add that support.
I will post the modification later since I'm not on my gentoo box right now. |
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Splooshie123 n00b
Joined: 16 Apr 2012 Posts: 27
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Posted: Wed Nov 07, 2012 9:57 am Post subject: |
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Here it is.
Put this file in /path/to/pommed-1.39-source-code/pommed, name it sysfs_backlight.c (replace the original), and compile:
http://pastebin.com/q7pL7xQh |
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