At the kernel >= 3.4 (samsung-laptop module) there has been appeared a Samsung RV520 laptop support (Product Name: RV420/RV520/RV720/E3530/S3530/E3420/E3520).

But the trouble with brightness adjustment exists:

When I try to change the brightness level, the maximum brightness limit becomes very low (~20...30%). Then, when I press <Fn + Up> (brightness up) further, a backlight is blinking for a short time, but the brightness level doesn't change. <Fn + Down> (brightness down) works well.

If I unplug the supply cable and then plug it back, the brightness level becomes maximum (100%). But after decreasing the brightness level the problem with <Fn + Up> repeats again.

> # cat /sys/devices/platform/samsung/backlight/samsung/max_brightness 
> 8
>
> # echo 8 > /sys/devices/platform/samsung/backlight/samsung/actual_brightness
> -bash: /sys/devices/platform/samsung/backlight/samsung/actual_brightness:
> Permission denied

But the backlight is blinking for a short time, if I execute this:

> # echo 8 > /sys/devices/platform/samsung/backlight/samsung/brightness

I've updated kernel up to 3.5.0 ― the situation is the same: after the brightness level decreasing it's not possible to increase it back higher some limited level. That's some console output (after <Fn + Down> to min and <Fn + Up> to "max"):

> $ cat /sys/devices/platform/samsung/backlight/samsung/actual_brightness 
> 2
>
> $ cat /sys/devices/platform/samsung/backlight/samsung/brightness 
> 8
>
> $ cat /sys/devices/platform/samsung/backlight/samsung/max_brightness 
> 8