亮度控制在戴尔 Inspiron N4010 笔记本电脑上不起作用

Question

我有一台戴尔 Inspiron N4010 笔记本电脑。我的亮度热键无法增加或减少屏幕亮度。事实上，我也无法从 下的Brightness & Lock菜单中降低亮度System Settings。任何解决方案？

编辑：我想我可能已经找到了问题背后的原因。在Ubuntu的先前版本有acpi_video0和intel_backlight里面/sys/class/backlight的文件夹。现在在 13.04 中有dell_backlight和intel_backlight在该文件夹中。最有趣的部分是，我的朋友在他的 Dell Vostro 上安装了 13.04，并且在他的系统/sys/class/backlight文件夹中有acpi_video0和intel_backlight。所以亮度热键对他有用。

Answer 1

我有相同的模型，并且在 13.04 开发过程中一直遇到相同的问题，直到发布前一天，然后它开始工作。我在这里提交了错误：错误#1105604：亮度控制停止工作

您可以做的是使用我在整个开发过程中使用的手动覆盖，修改/etc/rc.local如下：

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.
echo 978 > /sys/class/backlight/intel_backlight/brightness
chmod 777 /sys/class/backlight/intel_backlight/brightness
exit 0

缺点是除非手动修改文件，否则无法轻松更改亮度/sys/class/backlight/intel_backlight/brightness

当我确实让它工作时，我使用Fn+ 亮度键来检查设置：最低设置为490，之后它以488. 所以这些是默认设置/sys/class/backlight/intel_backlight/brightness：

490 Lowest with backlight on
978
1466
1954
2442
2930
3418
3906
4394
4882 Brightest

我的亮度控制以前可以工作，但又坏了，所以我决定创建一个脚本来管理它：

#!/bin/bash
# Dell N4010 brightness control workaround
# Note: add the following to /etc/rc.local
#       chmod 777 /sys/class/backlight/intel_backlight/brightness
# For convenience I've assigned the keys Alt-Up and Alt-Down to run this script
# Fine tune the bump parameter as required
#
# Usage:
#    ./brightchg.sh up   # bump up brightness
#    ./brightchg.sh down # bump down brightness
#
curr=`cat /sys/class/backlight/intel_backlight/brightness`
bump=244
if [ "$1" == "up" ]; then
  curr=`echo "$curr + $bump" | bc`
else
  curr=`echo "$curr - $bump" | bc`
fi
# Set the brightness to the new level making sure it's always above 30 (minimum usable)
if [ $curr -gt 30 ]; then
    echo $curr | tee /sys/class/backlight/intel_backlight/brightness
fi

注意：我添加了一行/etc/rc/local以授予我对亮度文件的权限：

chmod 777 /sys/class/backlight/intel_backlight/brightness

然后我将其分配给键Alt+Up和Alt+ Down，如下所示：