Re: Problem with backlight control and question about kernel information and patches
On Mon, 2011-08-29 at 01:52 +0100, Clea F. Rees wrote:
> I have no control over my laptop's backlight under Linux. This is a
> regression since it did work fine but I'm not certain exactly when it
> stopped working.
>
> I am very new to Linux but I think that the problem is that
> /sys/class/backlight/ is empty. That is, I know that the directory is
> empty but don't know enough to do more than think it is the source of
> the problem.
>
> This looks like a regression which might be fixed by the patch at
> https://patchwork.kernel.org/patch/499221 but I do not know enough to
> have any clue whether this is the case or not. In fact, I am not even
> certain how to tell if the kernel I'm using has this patch applied (or
> if it has even been merged upstream). I have read significant amounts
> of documentation, but nothing I've learnt has had much bearing on this
> particular problem so far. (I may well be looking in the wrong place.
> In that case, a pointer would be hugely appreciated - it took me
> several days to realise I needed to look for "backlight" rather than
> "brightness".)
>
> I haven't found reports of this problem with my particular laptop but
> the problem is described on other laptops as being fixed by patch
> 499221. So I'm not sure.
The patch looks specific to ACPI, which only applies to x86.
> uname info: 3.0.0-1-powerpc #1 Sun Jul 24 13:59:10 UTC 2011 ppc GNU/Linux
>
> Machine is a 12" G4 Aluminium PowerBook with a 1.5 GHz processor and a
> nvidia graphics card so I'm using the nouveau drivers.
Then it sounds like nouveau doesn't support backlight control on your
PowerBook yet. Or maybe the kernel is just missing some build
configuration. You should probably talk to the nouveau kernel
developers.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Debian, X and DRI developer
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