G3 iBook LCD brightness in X under kernel 2.4.25 and 2.6.8

Frank Murphy murphyf+xfree86 at f-m.fm
Mon Nov 29 07:14:46 EST 2004

On Sunday 28 November 2004 2:58, Benjamin Herrenschmidt wrote:
> >
> > So I've tried this using the stock Debian 2.6.8 and 2.6.9 PPC kernels
> > with the same results.
> >
> > $ grep ATY /boot/config-2.6.9-powerpc
> > CONFIG_FB_ATY128=y
> > # CONFIG_FB_ATY_XL_INIT is not set
> >
> > It seems that the atyfb module is compiled in. Is there another way to
> > check?
> Check the bits in CONFIG_PMAC_BACKLIGHT in atyfb (like, add some
> printk's to see if they are reached etc..)

So I added a couple of printk()s like you asked. I added one to 
aty128fb_blank() in aty128fb.c:2037 and two to aty_init() in 
atyfb_base.c:1793 and 1802 (inside the 'if (M64_HAS(MOBIL_BUS))'). The one I 
added to aty128fb didn't print (as expected), but both of them from 
atyfb_base.c printed. So it seems that CONFIG_PMAC_BACKLIGHT is properly 
defined. Anything you'd specifically like me to try?

I find it interesting that in the console the dimming works. I thought that on 
PPC the console used the framebuffer. Another notable thing is that while in 
X, the dimming doesn't work, but when I switch to one of the VTs, the screen 
brightness is adjusted to what it should have been in X.

Thanks for your help on this,


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