On Tue, Mar 13, 2012 at 08:09:52AM -0400, Pradeep Subrahmanion wrote:

Before taking this approach , I had a look at the WMI interface.But I found from acer-acpi site that , the 4730 series 
is using new WMI interface which needs to be reverse engineered.
As far as  acpi interface is concerned , by default it is not at all causing any change in brightness.
When 'acpi_osi=Linux' was added to the boot grub config , the brightness control with hot key started to work .
But it was not changing to correct values. Increasing brightness after maximum level gives blank screen.

That page was last updated in 2009. Have you tried the current acer-wmi 
code? You'd probably need to pass backlight=vendor if there's a 
non-working ACPI interface.

When you say the ACPI interface doesn't work, what do you mean? Have you 
tried using the /sys/class/backlight interface directly?

-- 
Matthew Garrett | mjg59@srcf.ucam.org