Rational for having CONFIG_FB_RADEON=m

[Mathieu Malaterre]

Dear all,

Debian decided to switch to using CONFIG_FB_RADEON=m (Mach64 and
Rage128 are still built-in). Since CONFIG_FB_OF=y and can never be a
module,  this means for PowerMac+radeon users that Open Firmware is
always the implementation taken from the Frame Buffer:

[    0.740726] Using unsupported 800x600 ATY,RockHopper2_A at
9c008000, depth=8, pitch=1024
[    0.750458] Console: switching to colour frame buffer device 100x37
[    0.759850] fb0: Open Firmware frame buffer device on
/pci at f0000000/ATY,RockHopper2Parent at 10/ATY,RockHopper2_A at 0

And:

$ cat /proc/fb
0 OFfb ATY,RockHo

Since also `radeonfb` is not capable of kicking out `offb` this means
I cannot `modprobe radeonfb`:

[   96.551486] radeonfb 0000:00:10.0: enabling device (0006 -> 0007)
[   96.551526] radeonfb 0000:00:10.0: BAR 0: can't reserve [mem
0x98000000-0x9fffffff pref]
[   96.551531] radeonfb (0000:00:10.0): cannot request region 0.
[   96.551545] radeonfb: probe of 0000:00:10.0 failed with error -16

So I have two options:

1. Try to convince debian-kernel team to switch back to
CONFIG_FB_RADEON=y (this will conflict with results from:
https://bugs.debian.org/614221)
2. Try to fix `radeonfb` so that it is able to kick offb out of the
way. Eg: https://lists.freedesktop.org/archives/dri-devel/2010-August/002907.html

>From my understanding it would make sense to go for (2), since it
would allow for proper support for CONFIG_FB_RADEON=m on PowerMac. In
this case, would such patch be accepted ?

Thanks