Disable the ambient light sensor

Introduction
The N900 contains a Taos TSL2563 Ambient Light Sensor (ALS). This light sensor is used to auto-adjust the screen brightness relative to your preferred brightness setting. Some users may find this auto-adjusting to be annoying, when the screen dims every time you hold your finger over the screen, or trying to use the phone outdoors.

Prerequisites
You will need to install the rootsh package.

Disabling the ALS
TMO user dr_frost_dk discovered a simple way to disable the ALS: sudo gainroot sed -ie 's/brightness-als/brightness-simple/' /etc/mce/mce.ini Then reboot and the new setting should take effect.

Please note that the actual ALS device is not disabled; it still functions and can be used by other applications. This setting only disables its influence on the backlight.

Re-enabling the ALS
If you want to change back to the original setting: sudo gainroot sed -ie 's/brightness-simple/brightness-als/' /etc/mce/mce.ini Then reboot and the backlight will once again be influenced by the ALS.