Freaky notebook LCD brightness control problem with Nvidia Vista drivers
This is rather note to my self then a post. If you are using modded inf to install new workstation (180.x) GeForce drivers to a notebook (from for example here), brightness control via function keys will behave strange. Strange as in - it won't fade at all or will fade, but in strange steps. You can notice hard screen flickering when dimmed.
Solution is to add this to nv_disp.inf:
[nv_SoftwareDeviceSettings_G8x] ... ;Smart Dimmer Controls HKR,, EnableBrightnessControl, %REG_DWORD%, 1 HKR,, PanelPWMFrequency, %REG_DWORD%, 210 HKR,, PanelPWMDutyRange, %REG_DWORD%, 0x03E80096...
When I first noticed this behavior I thought that my laptop is dying in slow and horrible death. I updated really old drivers packed with laptop with new modded ones. Late in the evening I use to dim my screen a bit, but after driver update brightness control via function keys would fade the screen in such a nasty way which definitely reassembles laptop screen dying. Beside the brightness problem, the Powermizer would dim the screen to black (instead of a very dark but visible setting), and screen wouldn't lit up after laptop has woke from stand by.
New modded drivers didn't contain above three laptop manufacturer specific settings and that caused all the problems. It's also interesting to note that brightness control in Vista's original VGA driver works flawlessly. So to completely rule out hardware failure, test your screen with those drivers.
Each time I update drivers in such a manner, I am happy that my hardware doesn't melt. And yes, I've tested above settings on Samsung and Asus laptop and brightness control worked as with original driver set. Hooray! )