I want to reduce the minumum brightness of the screen of my Toshiba Excite Pro tablet. This is a tablet which (as far as I can tell) is essentially impossible to root, but I want to change the brightness of the screen, the value of which is stored in a file in the /sys/ directory of the tablet's filesystem. I want to change the value stored in this file from "35", to, say "10". Is there any way I can do this? For example:

  • a way of temporarily getting permissions to alter this file without fully rooting the device
  • an app which does not require root which reduces brightness beyond the default minimum
  • or if there is, indeed a way to root this device now, that would be good.

Note: I'm not looking for an app which will put a filter over the screen to darken it; I want to turn down the screen as it's the biggest consumer of energy and I want to increase battery life.

Edit: I want to change this file as 35 is the minimum screen brightness. The system settings for some reason have a very narrow range of allowed brightnesses.



I used to have your idea and I gave it a try, but to no avail. I rooted my phone and did the following

echo 1 > brightness

... but it seems to be identical to its lowest value, which is in my case, 20.

The mininum brightness is something in the screen's firmware, which is even beyond the Linux kernel. You can't change it unless you flash a custom firmware to your screen, and it will almost surely destroy it, so don't attempt to do so.

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