Backlight control on iMAC G5 8,1

[Justin Hibbits]

On Tue, 3 May 2016 23:17:07 +0200
Daniel Sharoh <dsharoh at gmail.com> wrote:

> Hi everyone,
> 
> Sorry if this is the wrong place for my question. Maybe I should ask
> on IRC instead?
> 
> I'm new to freeBSD and BSD in general, but am a long time linux user.
> I have an iMac G5 that I've installed freeBSD 10.2 on, and it's
> generally working well. This system uses the ATI Radeon 9600 graphics
> card, and I am using the ati-ums driver with X because the the
> regular ati driver won't build on my system (it says intel only when
> I try to build it). One major problem I have with my system is that I
> cannot control the backlight level.
> 
> For example 'sysctl dev.backlight.0.level=0' has no effect.
> 'xset dpms force off'  blanks the screen but leaves the backlight on
> 
> When I query sysctl dev.backlight I get
> 
> dev.backlight.0.level: 2956
> dev.backlight.0.%parent: vgapci0
> dev.backlight.0.%pnpinfo:
> dev.backlight.0.%location:
> dev.backlight.0.%driver: backlight
> dev.backlight.0.%desc: PowerBook backlight for nVidia graphics
> dev.backlight.%parent:
> 
> Which seems suspicious because I don't have an nVidia graphics card.
> 
> I see atibl.c in /usr/src/sys/powerpc/powermac/, but that module isn't
> available in /boot/kernel/ or /usr/src/sys/modules
> 
> Does anyone have any idea what I could do? I haven't been able to
> find any information, probably because I'm new to BSD and ask the
> wrong questions.
> 
> Another unrelated problem is that I don't have any control over the
> hardware volume using 'mixer.' Programs like mplayer can use software
> control, as in this post
> https://lists.freebsd.org/pipermail/freebsd-ppc/2014-January/006796.html,
> but it would be nice to have hardware control. Is this currently
> achievable on the iMac 8,2?
> 
> Thanks!
> Dan
> 
> 

Hi Dan,

The atibl driver is built into the kernel, I never made it compileable
as a module, nor nvbl.  There is a bug in stable/10, which I've fixed in
head, regarding the backlight drivers.  In stable/10, the drivers only
check the device type, which I learned later is insufficient, so the
drivers now, in head, check the PCI device ID as well, so the driver
should work properly for you in head.

Regarding the mixer, that driver has not been written yet.
Unfortunately most of us who work on powerpc don't have much time
lately, or the hardware to test with.  I don't know if there's a bug
filed for it, but if not, could you file a bug, and also post the
output of 'ofwdump -ap' into the bug?

- Justin