Bug#683796: xserver-xorg-video-radeon: No 3D acceleration in iBook2 powerpc

Michel Dänzer daenzer at debian.org
Tue Aug 14 07:58:55 PDT 2012

On Don, 2012-08-09 at 05:11 -0700, Dan DeVoto wrote: 
> --- On Wed, 8/8/12, Michel Dänzer <daenzer at debian.org> wrote:
> > > 
> > > I heard that this handover from OFfb to radeon KMS can
> > cause problems in
> > > some cases. Maybe you can try adding video=offb:off to
> > > video=radeonfb:off .
> > 
> > BTW, does the black screen occur only when X starts, or
> > already when KMS
> > takes over from OFfb, which according to the above happens
> > about 10
> > seconds after the kernel starts booting?
> The black screen happens about 10 seconds after boot starts when the
> line appears onscreen:
> fb: conflicting fb...(it didn't give me time to read the rest, but I
> assume it's "fb: conflicting fb hw usage radeondrmfb vs OFfb
> ATY,Fall_A - removing generic driver").
> Just to be clear about the symptoms, the screen is still lit, it's
> just colored black and there's nothing visible. Then when X starts in
> the boot process, the screen goes dark for a second as if it's powered
> off, then comes on again to a lit but black screen, then after another
> second switches to a slightly lower brightness level. When I switch to
> a console, something similar happens. Also, I can change the
> brightness of the black screen with the iBook's brightness keys.

Okay, that sounds like there's no problem with the backlight, but for
some reason the LCD is programmed to show only black.

> I added video=offb:off to video=radeonfb:off like you suggested but
> got the same result.

Did you verify in dmesg that this resulted in OFfb being completely
disabled? I.e. no messages from OFfb, in particular nothing about
'conflicting fb hw usage'? Maybe just provide the dmesg output from that

Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer

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