On open video driver problems with brightness control almost was not. Put the site amd latest drivers - not regulated. Neither fn Fx, or the menu to control brightness. Precisely controlled, but not always correctly. For example, if 10 times press Fn F2 (decrease brightness) - it is reduced by one or two points (although the slider goes with each press) and that does not always work. Installed samsung-tools - all the Fn keys work correctly, such as variable speed fan. But the brightness still not regulated. samsung-backlights for 12.10 is not available in the repositories, installed from the repositories 12.04 - did not help. Changed the line in the GRUB (finishing acpi_backlight = vendor to the parameters), finishing laptop model in the file / lib/udev/rules.d/95-keymap.rules - to no avail. The buttons perform their actions, but the brightness is changed by one seat. Apparently, it's the driver. And yet, when the system idle brightness decreases - after the resumption of the back is not added. Nobody faced similar?
P.S.: It was found that:
$ echo num_from_1_to_7> / sys/class/backlight/acpi_video0/brightness
Almost never works the first time. Maybe the 10th work, can the second, but it is very rare that switches the lights at once.
Do not know if there is a log file, which is written in this information? in /var/ log by date changes are not found.
I would be very grateful for the help...
P.P.S.: Sorry for my english