Hi Andreas,
The default ppc64 kernel as supplied by Debian has been configured with
64KB kernel pagesizes. At least valid since the last time i have checked.
I have been building my own kernels for a while, haven't used a default
Debian kernel for a while.
I believe the change to the default Debian kernel pagesize config for
ppc64 kernel builds was made around jessie!
The nouveau driver currently doesn't work with anything other than 4KB
kernel pagesize.
This isn't much of a surprise since x86 and amd64 both use 4KB pagesize
which is more or less the target market (also ppc32 used 4KB kernel
pagesize).
To correct this, unfortunately you need to modify the kernel config and
build your own custom kernel.
Otherwise you may use kernel deb packages that i have prepared earlier,
otherwise you can build your own kernel.
Also, for many of the the nVidia GPU's commonly found in PMAC 11.2, the
nouveau driver currently defaults to MSI interrupts.
I have tested the equivalent GPUs (NV47 with x86 VGA BIOS for instance
in an amd64 box) and the MSI interrupts seem to work fine with the
particular GPU running the nouveau driver.
So it seems that the issue is that currently the nVidia GPU's running
the nouveau driver on ppc64 arch, you must disable MSI interrupts.
There are various methods of doing this, however i tend to pass module
parameters instead of passing options on the kernel command line. Each
to their own i guess.
For both of these issues, IIRC it doesn't seem to affect the nouveau fb
console, however once you attempt to get xorg up and running, you will
soon get a gpu lockup... forcing you to reboot.
Lastly, kernel versions between 3.18.16 & 4.3.0-rc6 had issues
extracting the DCB block from the OpenFirmware fcode ROM used in the oem
nVidia GPU's sourced from Apple. There was a workaround for this,
however if you use a suitable kernel version, the workaround doesn't
need to be applied.
Best Regards,
Peter