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Re: Debian 8 on Late 2005 G5, Graphics Issues

Hello Peter,

amazing thx for pointing this out, we need to preserve and document this information as detailed as possible.

Based on the details you mentioned someone could add information to the ppc faq and known issues/ workaround intructions, but it might be best if you did it yourself, seeing as you came up with the workaround and know the details behind it and likely could describe things more thoroughly. Also a bug report on it could help, always good to know whats causing issues and where exactly so it may be fixed at a later time.

https://wiki.ubuntu.com/PowerPCKnownIssues  (should absolutely be in here)

https://wiki.ubuntu.com/PowerPCFAQ (could be added in here as well but this page is a lot less recent and not as helpful)


Am 29.06.2015 08:06 schrieb "Peter Saisanas" <psaisanas@gmail.com>:



I also have a Powermac G5 Quad and tried with both the Geforce 6600 and Quadro FX4500 video cards and I have successfully gotten it up and running using the nouveau driver along with 2D acceleration on the XOrg desktop. I have compiled many newer kernels and created debian packages for them. Newer 4.0+ kernels also have issues in terms of detecting the nvidia DCB from the FCODE ROM… But there are other workarounds for this to get it up and running. You shouldn't need to use the boot parameter "nouveau.noaccel=1" once you have properly configured your kernel. 


In my case, the reason why X does not seem to work with your configuration is twofold:


The recent Debian (and Fedora) kernels for PowerPC 64 Bit running on the G5 64bit powermac are configured with a 64Kb kernel pagesize. This works slightly better in terms of performance, however the nouveau driver does not support this size. You must recompile the kernel unfortunately and configure with 4Kb kernel pagesize as this is what nouveau will work with for now.


To confirm, run the following command in a shell as root:

“getconf PAGESIZE”

If it returns 65536, you are using a 64Kb pagesize kernel.

Otherwise if it returns 4096, i.e. 4Kb kernel pagesize, check the next item below.


The newer nouveau drivers in more recent kernels default to using MSI interrupts, however with the PPC G5, when using  MSI interrupts, the powerpc FCODE rom on Nvidia cards does not correctly set up the MSI address (or vector).


To confirm, run the following command in a shell as root:

“cat /proc/interrupts”


Look for the nouveau interrupt, if it is using MSI interrupts, you need to disable MSI interrupts either by passing the option to the nouveau module, disable MSI interrupts by passing an option to the kernel command line in yaboot.conf or disable MSI interrupt support in total when compiling a new kernel. If configured correctly, nouveau should be using level or edge interrupts.



This is what worked for me anyway.





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