如何在‘/sys/class/backlight`’中的选项之间切换以解决亮度问题？

Question

操作系统: Ubuntu - 18.04 LTS

我在/sys/class/backlight/目录中有两个符号链接。

acpi_video0 -> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/backlight/acpi_video0/
nv_backlight -> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0/card0-LVDS-1/nv_backlight/

亮度热键会改变acpi_video0/brightness的值。但这并没有改变显示器的亮度。

但是，手动更改nv_backlight/brightness的值实际上会改变显示器的亮度。

因此，将热键链接到nv_backlight而不是acpi_video0将解决我的问题，但我不知道如何做。

编辑:弹出滑块进度条出现在屏幕上的Fn键的操作亮度(热键)。

编辑：

1. 输入: cat /sys/class/backlight/nv_backlight/max_brightness输出: 100
2. 输入: cat /sys/class/backlight/nv_backlight/actual_brightness输出(此值自动更改为相同的值，手动输入到/sys/class/backlight/nv_backlight/brightness)：10
3. 输入: cat /sys/class/backlight/acpi_video0/max_brightness输出: 15

Answer 1

Bash脚本redirect-brightness

您的问题是要增加/降低亮度的函数键正在更新/sys/class/backlight/acpi_video0/brightness而不是/sys/class/backlight/nv_backlight/brightness。

最初的请求是拦截函数键并使用它们来控制nv_backlight驱动程序。这方面的问题是：

• 棘手的udev脚本
• 没有弹出通知滑块显示亮度，没有复杂的Python脚本。

解决方案是使用inotify来监视对acpi_video0的更改。然后计算亮度百分比并将该百分比应用于nv_backlight。

在下面的bash脚本中，您需要设置：

WatchDriver="/sys/class/backlight/acpi_video0/brightness"
PatchDriver="/sys/class/backlight/nv_backlight/brightness"

将脚本放置在/usr/local/bin中，并使用以下方法使其可执行：

chmod a+x /usr/local/bin/redirect-brightness

首先从命令行运行脚本，使用

redirect-brightness -l

如果出现问题，请使用以下方法检查日志文件：

cat /tmp/redirect-brightness.log

如果一切正常，那么将redirect-brightness添加到启动应用程序中。

redirect-brightness bash脚本

#!/bin/bash

# NAME: redirect-brightness
# PATH: /usr/local/bin
# DESC: Redirect to correct driver when Ubuntu is adjusting the wrong
#       /sys/class/DRIVER_NAME/brightness

# DATE: June 13, 2018. Modified June 14, 2018.

# NOTE: Written for Ubuntu question:
#       https://askubuntu.com/q/1045624/307523

WatchDriver="/sys/class/backlight/intel_backlight"
PatchDriver="/sys/class/backlight/intel_backlight"

# Must be running as sudo
if [[ $(id -u) != 0 ]]; then
    echo >&2 "Root access required. Use: 'sudo redirect-brightness'"
    exit 1
fi

# inotifywait required
type inotifywait >/dev/null 2>&1 || \
    { echo >&2 "'inotifywait' required but it's not installed.  Aborting."; \
      echo >&2 "Use 'sudo apt install inotify-tools' to install it.'"; \
      exit 1; }

# Was right watch driver directory name setup correctly?
if [[ ! -d $WatchDriver ]]; then
    echo >&2 "Watch directory: '$WatchDriver'"; \
    echo >&2 "does not exist. Did you spell it correctly? Aborting.'"; \
    exit 1;
fi

# Was right patch driver directory name setup correctly?
if [[ ! -d $PatchDriver ]]; then
    echo >&2 "Redirect to directory: '$PatchDriver'"; \
    echo >&2 "does not exist. Did you spell it correctly? Aborting.'"; \
    exit 1;
fi

# Get maximum brightness values
WatchMax=$(cat $WatchDriver/max_brightness)
PatchMax=$(cat $PatchDriver/max_brightness)

# PARM: 1="-l" or "--log-file" then write each step to log file.
fLogFile=false
if [[ $1 == "-l" ]] || [[ $1 == "--log-file" ]]; then
    fLogFile=true
    LogFile=/tmp/redirect-brightness.log
    echo redirect-brightness LOG FILE > $LogFile
    echo WatchMax: $WatchMax PatchMax: $PatchMax >> $LogFile
fi

SetBrightness () {
    # Calculate watch current percentage
    WatchAct=$(cat $WatchDriver/actual_brightness)
    WatchPer=$(( WatchAct * 100 / WatchMax ))
    [[ $fLogFile == true ]] && echo WatchAct: $WatchAct WatchPer: $WatchPer >> $LogFile
    # Reverse engineer patch brightness to set
    PatchAct=$(( PatchMax * WatchPer / 100 ))
    echo $PatchAct | sudo tee $PatchDriver/brightness
    [[ $fLogFile == true ]] && echo PatchAct: $PatchAct >> $LogFile
}

# When machine boots, set brightness to last saved value
SetBrightness

# Wait forever for user to press Fn keys adjusting brightness up/down.
while (true); do
    inotifywait --event modify $WatchDriver/actual_brightness
    [[ $fLogFile == true ]] && \
        echo "Processing modify event in $WatchDriver/actual_brightness" >> $LogFile
    SetBrightness
done

原始答案2018年6月11日.

工作正在进行中回答

在Ubuntu18.04中有许多类似问题的nVidia用户：

• Ubuntu18.04笔记本电脑MSI GT72VR上的亮度与NVIDIA 1060手机不工作
• 计算机不会从悬挂中醒来，也不会改变亮度
• 使用Nvidia驱动程序时亮度控制丢失，但与X.Org一起重新出现。
• Xubuntu18.04:使Fn亮度键与/sys/class/backlight/nv一起工作_背光/
• 如何在lubuntu中改变背光驱动程序
• Ubuntu18.04笔记本电脑MSI GT72VR上的亮度与NVIDIA 1060手机不工作
• NVIDIA显示问题与亮度控制和视频播放
• 无法更改屏幕亮度
• 笔记本电脑屏幕的亮度不能用按钮或滑块来调整。编辑

编写脚本之前的

(

)

我可以编写一个脚本来模拟对/acpi_video的更改并填充/nv_backlight，但在尝试之前：

• 编辑/etc/default/grub。
• 寻找quiet splash
• 添加背后的飞溅：acpi_backlight=vendor
• 保存文件
• 运行sudo update-grub

根据这个答案，它应该适用于您：Xubuntu18.04:使Fn亮度键与/sys/class/backlight/nv一起工作_背光/

Wayland

亮度在Wayland下是不起作用的。确保你没有使用它。请参阅：笔记本电脑屏幕的亮度不能用按钮或滑块来调整。编辑