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Anyone find a work around for the brightness issues from kernels 5.13/14? - Printable Version

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Anyone find a work around for the brightness issues from kernels 5.13/14? - ragreenburg - 08-31-2021

I have the UBports version on the pinephone and with bother kernels 5.13 and 5.14 I get an issue where if I turn the brightness down all the way the screen goes black. I noticed a few threads on here from a while ago talking about it but was wondering if anyone found a solution?


RE: Anyone find a work around for the brightness issues from kernels 5.13/14? - Zebulon Walton - 08-31-2021

I set up /etc/rc.local to set brightness at boot time before upgrading to the 5.13 kernel. If you do this and accidentally turn the screen off, rebooting the phone will bring the screen back. If you have ssh access you can do it from the command line.

On Mobian, rc.local is not enabled by default, you have to set up a systemd unit file for it. This is the command to run at boot or from ssh as root:

echo 400 > /sys/class/backlight/backlight/brightness

(The number "400" is an example, higher number is brighter screen. I'm actually using 600 - not sure what the max is.)


RE: Anyone find a work around for the brightness issues from kernels 5.13/14? - ragreenburg - 09-01-2021

(08-31-2021, 05:41 PM)Zebulon Walton Wrote: I set up /etc/rc.local to set brightness at boot time before upgrading to the 5.13 kernel.  If you do this and accidentally turn the screen off, rebooting the phone will bring the screen back. If you have ssh access you can do it from the command line.

On Mobian, rc.local is not enabled by default, you have to set up a systemd unit file for it.  This is the command to run at boot or from ssh as root:

echo 400 > /sys/class/backlight/backlight/brightness

(The number "400" is an example, higher number is brighter screen. I'm actually using 600 - not sure what the max is.)

Shoot, I figured this was a case. I was hoping there was a way to set up a minimum/maximum brightness in the settings or in `sys/class/backlight` somewhere.