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On Wed, Jan 7, 2009 at 9:47 PM, Paul Hartman |
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<paul.hartman+gentoo@×××××.com> wrote: |
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> On Wed, Jan 7, 2009 at 8:29 AM, Momesso Andrea <momesso.andrea@×××××.com> wrote: |
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>> I'd like to make the file /sys/class/backlight/asus-laptop/brightness |
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>> writeable for users, so that I don't need to be root anymore to change |
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>> the brightness. |
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>> |
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>> Of course I can chown or chmod ot in local.start but I'm asking if there |
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>> is a cleaner way. |
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> |
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> I guess you need to use udevinfo to get the important information |
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> about /sys/class/backlight/asus-laptop/brightness and then write up a |
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> rule, slap it into a file in /etc/udev/rules.d/ and enjoy your new |
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> permissions. :) I don't have that device on my system so I can't |
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> really suggest anything more specific. |
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> |
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> Here's a udev rules HOWTO that might help: |
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> |
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> http://www.reactivated.net/writing_udev_rules.html |
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> |
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> (specifically "Controlling permissions and ownership") |
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> |
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> Good luck :) |
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> Paul |
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> |
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> |
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|
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It looks like I cannot simply write a rule to change that permission... |
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After experiencing some failures I guess that udev rules can change |
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permissions on /dev/ files, but not on /sys/ files... |
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|
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This is my case: |
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|
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# udevadm info -a -p /sys/class/backlight/asus-laptop/ |
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|
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looking at device '/class/backlight/asus-laptop': |
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KERNEL=="asus-laptop" |
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SUBSYSTEM=="backlight" |
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DRIVER=="" |
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ATTR{bl_power}=="0" |
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ATTR{brightness}=="5" |
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ATTR{actual_brightness}=="5" |
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ATTR{max_brightness}=="15" |
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|
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And this is the rule I added in /etc/udev/rules.d/10-local.rules |
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|
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KERNEL=="asus-laptop", SUBSYSTEM=="backlight", GROUP="video", MODE="0660" |
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|
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After a reboot I still get this: |
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|
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# ls -la /sys/class/backlight/asus-laptop |
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total 0 |
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drwxr-xr-x 3 root root 0 2009-01-09 15:18 . |
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drwxr-xr-x 3 root root 0 2009-01-09 15:18 .. |
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-r--r--r-- 1 root root 4096 2009-01-09 15:18 actual_brightness |
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-rw-r--r-- 1 root root 4096 2009-01-09 15:19 bl_power |
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-rw-r--r-- 1 root root 4096 2009-01-09 17:02 brightness |
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-r--r--r-- 1 root root 4096 2009-01-09 15:18 max_brightness |
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drwxr-xr-x 2 root root 0 2009-01-09 15:19 power |
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lrwxrwxrwx 1 root root 0 2009-01-09 15:18 subsystem -> ../../backlight |
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-rw-r--r-- 1 root root 4096 2009-01-09 15:18 uevent |
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|
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Googling a bit I found some solutions [1] [2], but all of them are |
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changing the permissions at every |
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boot. It works, but it looks to me a bit unclean... |
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[1] http://wiki.laptop.org/go/Xfce_keybindings#Adjust_screen_brightness_buttons |
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[2] http://www.thinkwiki.org/wiki/Automatically_reduce_brightness |
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|
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-- |
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Momesso (TopperH) Andrea |
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http://topperh.blogspot.com |
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Jabber: topper_harley@××××××.org |
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ICQ: 224179391 |