[Linux-fbdev-users] platinumfb display on a powermac 7200

[Tomasz G. <tom...@gm...>]

Hi all,

I've reposted my bug report on the list (following the procedure the
wrong way around, I know, sorry!) to get some ideas..

I managed to get my hands on a PowerMac 7200 and am
trying to boot. I (cross) compiled a kernel of
2.6.16.16 from a gentoo x86 box, and serially connected
the machine to view the console output results. I have
stripped out basically everything (no IDE, SCSI, USB)
except serial, framebuffer, console and ADB.

The framebuffer won't enable using the platinumfb for
the life of me when using BootX from a MacOS 7.6.1
installation on another hard drive. I've dropped a new
AHA2940 (bios flashed to OpenFirmware) SCSI card with
another attached hard drive to it (8GB of SCSI
goodness) so I can hack away at the MacOS to my hearts
content.

I have a successful installation of Debian 3.1 on this
HDD from a previously successful attempt some months
ago using the miboot boot/root install set from:
http://people.debian.org/~luther/d-i/sid/images/daily/
The daily builds I tried were 18-20 May 2006, and while
I believe the kernel has booted okay (since I can
insert the root floppy and hit enter and it does
something) I can't see anything on the screen.

I have a native mac monitor, MacOS runs at 640x480
happily. I can boot the debian/woody kernel (2.2)
series with the platinumfb driver, and zapola
everything is okay. I get screen output. I can boot off
one of my custom built 2.6.x kernels, specifying the
serial console as a the console=3D... parameter and sure
enough the system comes up without a hitch except that
the monitor is in 'off' mode. I have tried kernels
2.6.17-rc4, 2.6.16, 2.6.15, 2.6.14 (cross-)compiled
from sources without any luck.

Using
http://www.jonh.net/lppcfom-serve/cache/1043.html, I
have tried to give also several boot paramters
(thankfully I'm using BootX to try this stuff out now,
because trying to recreate the miboot debian floppies
would not have made for easy testing), also without
luck. Some examples of failed boots follow:
video=3Dplatinumfb
video=3Dplatinumfb:vmode:6,cmode:8
video=3Dplatinumfb:vmode:13,cmode:8
.. all with the same end result: no video.

Can I work with anyone on fixing this? It would be nice
to have some working miboots again, but unfortunately I
can't remember which daily build I downloaded when I
actually installed sarge some months ago. I *think* it
was 2.6.15, but I can't follow the same steps now
because the other modules can't be downloaded from
package repositories as sid is in 2.6.16-land now. I
have also tried the video=3Dofonly options when that
option is compiled in to the kernel (by the way, I am
always statically compiling the fb devices in), the
ofonlyboot image from the miboot series, also without
any joy. In my own compilations, I only ever use either
the platinumfb or the ofonly framebuffer devices
compiled in, not both at once.

I know (specifically) with the 2.6.17-rc4 kernel, the output
is there (sorta), but kind of skewed. So a line is kind of
skewed across the screen, and you can see dots coming up but
they're all with a very deep slant.
So a normal line would look like this:
..................................
What I get is this:
                      ..........
                  ...........
          ...............
       ..............

Maybe I can take a photo and upload a jpeg or something?
Seems like its (guessing here) writing to the wrong areas of
video memory (?).

-Tomasz