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 16.06.2012 04:52, schrieb Mattia Dongili:
> This is a known issue (at least to me) but it shouldn't really be a
> problem as it existed for quite some time. Reading the brightness level
> at boot returns an uninitialized value so the driver displays that
> negative number. After echoing below you should see the actual value you
> set.
Ok. Just wanted you to see it.

> this looks ok. I'm wondering if the nouveau driver may be getting in the
> way somehow or if I broke backlight support in sony-laptop.
I have no idea.

> Can you try applying the sony-laptop patches on 3.2, boot with
> acpi_backlight=vendor and see what is the state there?
It behaves just like 3.3. What might be interesting is 3.1. Here some
really strange values get returned:

[root@vpcs nv_backlight]# cat actual_brightness brightness max_brightness
1073864551
1073864551
1025

When setting brightness to something between 0 and 1025, the screen is
basically black. At least there seems to be no backlight.

> there are various (potentially conflicting) ways to control the
> brightness levels, acpi, platform and raw (via the video driver).
Any chance to get this thing sorted, so the right way of control will be
reported to Gnome (or for that matter any other instance in control of
brightness).

I'm currently trying to reconstruct the last version that worked for me.
I'm quite sure that "vaio-full-3.0.4.patch" (from here [1]), worked fine
with the 3.1.x branch. However I've just recompiled 3.1.10 and it
doesn't seem to work. Anyway it worked without the
"acpi_backlight=vendor" parameter, so I'm not quite sure whether this is
of interest for you right now.

Best regards,
Karol Babioch

[1] http://www.absence.it/vaio-acpi/source/patches/?C=M;O=D


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