Hello Peter! Thanks for your answer. I am currently installing Gentoo Linux in a chroot from the Debian installation. X.org is actually running, and I switched to a VT which surprisingly works stable in every way. To check it, I just stopped X.org by running "systemctl stop kdm" in one of the consoles. So it was running, but not interfering with the system.
dmesg shows the line: nouveau E[ DRM] GPU lockup - switching to software fbcon And then the "FUN" thing: after stopping kdm, I now got these messages (after about 2 minutes): nouveau E[Xorg[838]] failed to idle channel 0xcccc0001 [Xorg[838]] These messages repeat every ~15 seconds and ONLY THEN the system was not usable anymore. I could still switch consoles, and type in commands, but they were heavily delayed. I was then turning off kdm for the next boot, using "systemctl disable kdm" (delayed, but working). So here comes FUN #2: this solved the delay problem. System was usable again. I am now continuing to build Gentoo (without rebooting). For now. Hope this will not cause trouble. I think I will build a custom kernel later on. Also, I will play with Gentoo – once I get it up and running, I shall play with current nouveau, mesa and kernels. Maybe there are some fixes there already? Or I can apply the 2013 patches mentioned somewhere… Thanks again, Andreas aka Linux User #330250 Am 2016-01-04 um 22:50 schrieb Peter Saisanas: > 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 > >