![amd brightness control amd brightness control](https://y31uv4ra1.vo.llnwd.net/content/wp/tweaklibrary_com/uploads/2021/03/control-panel.png)
Once you have acpid running you can watch the events by running Next, make sure you have the acpid service installed/running: I was experimenting with removing this module, which causes the thinkpad_screen device to disappear, but in the end this module turned out to be necessary because the acpi events for the screen brightness buttons do not fire without it. First, ensure that you have the thinkpad_acpi module loaded. Well I accidentally fixed the problem while trying to debug it So it seems like the only issue here is that something (systemd? gnome?) is manipulating the wrong device in response to brightness inputs. If I echo values into /sys/class/backlight/amdgpu_bl0/brightness it does adjust the screen brightness correctly. It doesn't seem to support any other values. Also, when using the keyboard controls, I can only get the value of thinkpad_screen's brightness to toggle between 1 and 2. After some investigation I found that the brightness controls on the keyboard seem to be changing the brightness of the thinkpad_screen device rather than the amdgpu_bl0 device. I'm hitting a similar problem on my new P14s. No, I'm not going to do such hacks, it should be solvable without, I hope.
![amd brightness control amd brightness control](https://images.drivereasy.com/wp-content/uploads/2017/07/img_595b0a627401c-300x215.png)
thinkpad_screen is a virtual device and does not point to any real device. If the symlink solution works you may wish to make it permanent or just resign to echoing values to brightness to adjust it. Many failures when compiling,problems with polkit,problems with brightness etc etc etc. Normally you shoudnt be forced to do dirty tricks like that but from reading posts in this forum it appears plasma is a very glitchy product. If not maybe symlink amdgpu_bl0/brightness to thinkpad_screen/brightness (ln -sf)ĭo symlinks under /sys even work?Please experiment. They may be symlinks to a device.Is it the same?(ls -l) Last edited by equaeghe on Thu 8:12 am edited 1 time in totalĭoes thinkpad_screen/brightness and amdgpu_bl0/brightness point to the same device? Perhaps Plasma is writing to thinkpad_screen/brightness instead of amdgpu_bl0/brightness? How can I find out? Perhaps something else is wrong? I do not know what thinkpad_screen is its brightness is at 0 even though in reality this is not so. Putting a value in amdgpu_bl0/brightness changes the brightness. /devices/virtual/backlight/thinkpad_screen The kernel does support backlight changes: When increasing brightness, the levels shown are increasing in steps of about 6.5% (7-13-20-…), but the actual brighness does not change.When releasing the brightness control key for a moment, the brightness goes back to 0%. The brighness level shown is at 0% when reducing brightnes. When I use the brightness control keys, the brightness change overlay appears, but does nothing when changed. T14 AMD: brightness ctrl not effective under… Gentoo Forums Forum Index Kernel & Hardware
![amd brightness control amd brightness control](https://www.notebookcheck.net/fileadmin/Notebooks/Asus/C200MA-KX003/calman_colorchecker.jpg)