Apple Cinema Display Brightness Control
Clone this repository:
git clone https://github.com/warvariuc/acdcontrol.git
Change to program directory and compile it:
cd acdcontrol make
A new file
acdcontrol should appear in the same directory. If compiling failed, check if you
have installed packages necessary for compiling (e.g.
./acdcontrol [--silent|-s] [--brief|-b] [--help|-h] [--about|-a] [--detect|-d] [--list-all|-l] <hid device(s)> [<brightness>]
NOTE: You must have write permissions to this device in order to control the display being a user, not root. If you have no such permissions, you can either grant read/write permission to the world:
sudo chmod a+rw /dev/usb/hiddevX
or change the ownership:
sudo chown <your user name>:users /dev/usb/hiddevX
NOTE: It should be safe to run the program on other device than Apple Cinema/Studio display as the program checks whether the device is Apple display and warns about it.
- -s, --silent
- Suppress non-functional program output
- -b, --brief
- Print brightness value only when in query mode, otherwise ignored.
- -h, --help
- Show short help message and quit.
- -a, --about
- Show information about the program, some credits and thanks.
- -d, --detect
- Run program in the detection mode. In this mode no writes are performed to device so you can use any number of files if you are not sure that your monitor(s) are supported.
- -l, --list-all
- Lists all "officially" supported monitors and quits. If you do not see the device, this does
not mean that it won't work it simply means that I did not tested it on such a device. I'll
appreciate if you submit your information in the forum for any display that works hid device
device that represents your Apple Cinema display. It should be one of
When this option is specified, the operation is to set brightness, otherwise, the current brightness is retrieved. If brightness starts with
-, the current brightness is increased or decreased by that value. (Note: You have to place -- before the negative value!)
Brightness is a parameter ranged
[0-255]. Note, that not every value toggles the backlight power; different Apple Display models have different granularity. I use Apple Cinema 20" (clear plastic) and I'm feeling comfortable with the value of 160. I set 0, however, to see films in the darkness.
--briefoption and "Known Limitations" section.
In the following examples I assume that your HID device is
/dev/hiddev0. You may have it as
- acdcontrol --help
- Show long help message.
- acdcontrol --detect /dev/hiddev*
- Perform detection, which HID device is actually your display to be controlled.
- acdcontrol /dev/hiddev0
- Read current brightness parameter
- acdcontrol /dev/hiddev0 160
- Set brightness to 160. Note, that brightness setting depends on your model. Generally, this
parameter may get values in the range
- acdcontrol /dev/hiddev0 +10
- Increment current brightness by 10.
- acdcontrol /dev/hiddev0 -- -10
- Decrement current brightness by 10. Please,note
Currently, the display detection process is not fully automated as you need to specify a HID device path.
First time (after boot up) brightness is retrieved incorrectly (zero value), however, after it is set, the return value is correct. It shouldn't concern you much as Cinema/Studio Display stores actual brightness settings between the sessions.