Comment 31 for bug 1173961

Sorry about the lateness, school just started ad I'm kinda busy now. I
did what you said and it was working if I used high numbers like 200.
Also it is booting with this
> acpi_osi=Linux acpi_backlight=vendor
because that's the only way I've made the light go down.

On 08/25/2013 06:40 PM, Aaron Lu wrote:
> +Lee, the acer maintainer and sorry for the late reply.
>
> On 08/14/2013 12:14 PM, Maximiliano Oropeza wrote:
>> Ok, now there was a change. In *acer-wmi*, I put:
>>> root@Dayman:/home/maxo# cd /sys/class/backlight/
>>> root@Dayman:/sys/class/backlight# cd /sys/class/backlight/acer-wmi
>>> root@Dayman:/sys/class/backlight/acer-wmi# cat max_brightness
>>> 15
>>> root@Dayman:/sys/class/backlight/acer-wmi# 10
>>> 10: command not found
>>> root@Dayman:/sys/class/backlight/acer-wmi# echo 5 > brightness
>>> root@Dayman:/sys/class/backlight/acer-wmi# echo 7 > brightness
>> and there was no change at all.
>>
>> But when I went to *intel_backlight*, I got:
>>> root@Dayman:/sys/class/backlight/acer-wmi# cd
>>> /sys/class/backlight/intel_backlight
>>> root@Dayman:/sys/class/backlight/intel_backlight# cat max_brightness
>>> 976
>>> root@Dayman:/sys/class/backlight/intel_backlight# echo 5 > brightness
>>> root@Dayman:/sys/class/backlight/intel_backlight# echo 7 > brightness
>>> root@Dayman:/sys/class/backlight/intel_backlight#
>> and when I put echo 5 > brightness, the screen went super low, the same
> The intel_backlight's max_brightness could be very high so the value 5
> or 7 are almost identical to 0, you can try some larger values like 500
> or 2000 etc.
>
>> with echo 7. I tried changing the brightness using the FN keys and it
>> went at full brightness and once again I can't lower the brightness to
>> about half. Same problems as before but *intel_backlight* is the one
>> that actually changed brightness.
> Your system needs some quirk I suppose. BTW, your system only have two
> backlight interfaces acer-mi and intel_backlight, is it booting with
> acpi_backlight=vendor option?
>
> Thanks,
> Aaron