Re: no brightness with acpi video since 3.3 [was Re: Issues with the sony-platform module]

[Karol Babioch <karol@babioch.de>]

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Hi,

Am 17.06.2012 01:16, schrieb Mattia Dongili:
> I'm a bit lost at this point. Are you saying that you cannot get a
> working backlight control with the old set-up you had?
Yeah, I can't get it working. Tried nearly every kernel from 3.0
onwards. Don't know what is going on here :(. Any idea what could have
caused this?

> If so what else did you change in your set up?
Well, I'm on Arch Linux, which is a rolling release distribution. So
there is probably a lot of stuff, which has changed during the course of
the last two to three months :(.

> Also, any chance you could try to inspect/poke the acpi_video0 or
> sony-laptop backlight directories without loading the nouveau driver?
Yeah, sure. In both cases the brightness won't change. Here you have
some excerpts in the case of "acpi_backlight=vendor" again:

[root@vpcs ~]# grep . /sys/class/backlight/sony/*/*
/sys/class/backlight/sony/actual_brightness:-13
/sys/class/backlight/sony/bl_power:0
/sys/class/backlight/sony/brightness:-13
/sys/class/backlight/sony/max_brightness:242
/sys/class/backlight/sony/type:platform

I then echoed 100 to /sys/class/backlight/sony/brightness and dmesg
reported the following:

[   89.631235] sony_laptop: found handle 0x0137 (offset: 0x0b)
[   89.753455] sony_laptop: __call_snc_method: [SN07:0x000000000000020b]
[   89.753457] sony_laptop: called SN07 with 0x020b (result: 0x0000)

Not sure what this means, but probably nouveau is not the culprit here.

Best regards,
Karol Babioch


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