DDCI

[SL-RU]

Hello!

There are plans to add direct DDCI support? There are ideas how to implement it?

[Hummer12007]

Use the kernel module (see #76)
Though I didn't manage to get it working on my desktop with nvidia tbh :)

[sofiedotcafe]

Use the kernel module (see #76) Though I didn't manage to get it working on my desktop with nvidia tbh :)

Same, even on NixOS AMD (though, probably an different issue; see https://bbs.archlinux.org/viewtopic.php?id=282805).

For the time being, I just use ddcutil, i2c and some udev rules for it.

https://blog.tcharles.fr/ddc-ci-screen-control-on-linux/
https://def.lakaban.net/2021-06-25-ddcutil-controlling-the-brightness-of-an-external-monitor/

[Hummer12007]

If someone wants to add a backend that shells out to ddcutil to fix this while there is no viable way to do things using sysfs (and it doesn't seem like anyone upstream is interested to merge the driver or work on promised alternative stuff for years), I would not be against merging the PR.

[Hummer12007]

@SL-RU @sofiedotcafe please try this random piece of code i got by reducing the libddciutil examples (link it agains -lddcutil, depends on ddcutil, and your distro packaging the shared library): https://paste.sr.ht/~hummer12007/5fd8573abcdb8671aa9fa45aff7b50c73a99abe9

Does it do what's expected? (I won't get access to any monitor for the next 2 months)

[rcorre]

@Hummer12007 I gave it a try, it worked for me!
Gigabyte M28U monitor, Nvidia 3080 GPU.

/tmp via  v14.2.1-gcc 
✦ ❯ ./example 
1 displays found
Max Brightness: 100
Current Brightness: 60
Setting brightness to 50
New Current Brightness: 50
Setting brightness to 0

[djsigmann]

Any chance this issue could see some movement? DDCI support would be great.