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SubjectRe: [PATCH] Added backlight driver for Acer Aspire 4736
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On Tue, 2012-03-13 at 13:34 +0000, Matthew Garrett wrote:
> On Tue, Mar 13, 2012 at 06:56:16PM +0530, Pradeep Subrahmanion wrote:
> > I tried giving acpi_backlight = vendor . In that case hot key for
> > brightness control is working. But i think , it is not calculating the
> > correct value for brightness because increasing brightness after maximum
> > level gives blank screen .
> Which backlight device appears then?
>

'intel_backlight' appears when i gave option acpi_backlight = vendor. Writing to /sys/class/backlight/intel_backlight/brightness

does not cause any change in brightness.

> > By ' ACPI interface' , I mean 'acpi_video0' inside the
> > /sys/class/backlight. I havn't tried the /sys/class/backlight interface
> > directly . I will try that also.
>
> So writing values into /sys/class/backlight/acpi_video0/brightness does
> nothing?


No change in value when writing
to /sys/class/backlight/acpi_video0/brightness.

Another thing is that when i did boot with acpi_backlight = 'acer_wmi' ,
in new kernel (3.3.0-rc7) , it shows following messages ,

[ 8.350825] wmi: Mapper loaded
[ 10.363975] acer_wmi: Acer Laptop ACPI-WMI Extras
[ 10.396186] acer_wmi: Function bitmap for Communication Device: 0x91
[ 10.396385] acer_wmi: Brightness must be controlled by generic video
driver

Also there was no interface inside /sys/class/backlight for acer_wmi.

I also tried writing directly to Embedded controller register .But no
change.

----
Thanks ,

Pradeep Subrahmanion





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