Since the system don't store the last saved screen brightness level, this fix will set your desire value as default value for screen brightness in every system startup. It works on my HP mini 210 with Ubuntu 12.04 and Mint Debian 201204 but not on Linux Deepin 12.06.
Thanks to cmcanulty for providing another workaround which works on Linux Deepin by setting screen brightness to max, instead for Ubuntu fix.
- Open Terminal.
- Copy, Paste and Execute the following codes in Terminal.
sudo sed "s/\(GRUB_CMDLINE_LINUX=\)\"\"/\1\"acpi_osi=Linux acpi_backlight=vendor\"/" /etc/default/grub -i
There are different kinds of netbook/laptop around, so no guarantee is made that this workaround should work. Try at your own risk.