linux-3.3-rc2 and radeon kms failure on ppc32 with Radeon X1650PRO pcie

[Benjamin Herrenschmidt]

On Wed, 2012-02-15 at 03:23 +0100, acrux wrote:
> On Sun, 12 Feb 2012 11:00:43 +0100
> Michel Dänzer <michel at daenzer.net> wrote:
> 
> > On Sam, 2012-02-11 at 21:00 +0100, acrux wrote: 
> > > 
> > > Just a curiosity, i've only two powerpc machines[1] equipped with PCIE
> > > videocards and both them are not able to boot with radeonkms.
> > > Modern PCI-E videocards are not recognized by the old linux framebuffer
> > > subsystem and they solely can be managed by the new KMS frame buffer
> > > that doesn't work properly on Power Architecture.
> > 
> > That's too broad a statement, it works fine on other PowerPC machines
> > (PowerMacs, some embedded boards).
> > 
> 
> hi Michel,
> thanks a lot for your help, i really appreciate it.
> 
> If you say they were tested on real Power Architecture boards with PCIE
> videocards thus it is reassuring... and i'm happy that you understand
> my previus assertion wasn't affected by malevolence or sarcasm. Indeed
> i'm also a bit troubled 'n frustrated thinking that next release of
> mesa 'll do extend use of llvm (that doesn't work properly on linuxppc
> and totally untested on linuxppc64)
> 
> Btw, to sum up the list of Power Architecture machines with PCIE  that
> aim to be a desktop/workstation: Apple iMac G5 (iSight), Apple PowerMac
> Quad G5, YDL Powerstation 2x970MP and Acube Sam460ex . And the last
> two, on present evidence (my attempts), aren't able to boot up if
> bootkernel has kms enabled.

Which radeon card, kernel log please ? I've successfully booted various
reasonably modern radeons on these. I've also used gnome3 with GL
acceleration etc... on some of these. Granted that was a few month ago
so it's possible that something regressed.

>  Furthermore the first tree ones can
> fallback to the legacy OpenFirmware framebuffer and safely get a
> console.
> 
> > It looks like there's a problem with accessing the PCIe device memory,
> > and at this point it's not even 100% clear that this is due to a problem
> > in the driver, as opposed to e.g. in the platform code.
> > 
> 
> it could be the right problem and i've CC BenH that has a better global
> perspective.

Can you give me more data about the problem please ? It could be a
recent regression or some setup problem.

Also I've noticed on the PowerStation some issues where heavy DMA use by
a video card will eventually lock up the system. From what I can tell
this is an issue with the northbridge, though a Quad G5 with the same
bridge (tho not quite the same revision) doesn't show the problem. Could
be a configuration issue.

Cheers,
Ben.