Re: Panic at boot on 4/330 with cgfour and cgsix

[Julian Coleman <jdc%coris.org.uk@localhost>]

Hi,

> > > So I tried to boot a 4.0 kernel as it was the last one to have cgfour
> > > enabled by default and it had the same panic. I suspect this driver
> > > may not have been working for a very long time.
> >
> > It may be worth testing as far back as you can go - I think cgfour
> > support arrived in netbsd-1-2. Its unlikely to work if netbsd-4-0
> > didn't, but it is possible, and will be a big help if it does :)
> 
> I tried 1.5 which is the first version to list the cgfour as supported
> and it booted fine but I don't have a 1.5 user land set up to test
> further. Would it help if I set one up and tried to run X?

This is good news!  It would be useful if you are able to find the last
working version - that would narrow down the set of changes to look at.
I don't think that it's worth installing the userland, unless you do
want to run that older version.

I think that we can look at the changes between the last working version
and the first non-working one and see why the write is failing.  I wonder
if we end up writing to the wrong address for the framebuffer.  We might
need to build a version of the last working kernel with some extra debug,
but I think that we could do that using qemu.  I have qemu-system-sparc
running here, so it should be (relatively) straightforward to install the
version that works on the 4/330 in qemu and build custom kernels there
(I think that this would be easier/faster than using the real hardware!).


Regards,

Julian