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

On Mon, 27 Jan 2025 at 13:22, foo bar <[email protected]> wrote:
>
> On Mon, Jan 27, 2025 at 4:29 AM Julian Coleman <[email protected]> wrote:
> >
> > Hi,
> >
> > > So as the subject says I'm having problems with these two
> > > framebuffers. It seems to be related to the issue reported a few
> > > months ago here.
> >
> > > Luckily my cgfour is still working and I've attached a dmesg from
> > > current below. Any help would be appreciated.
> >
> > > 1152 x 900cpu0: data fault: pc=0xe80112e4 addr=0xfe02a000
> > > ser=0x8002<WRITE,SZERR>
> >
> > I tried to test 4/300 card, but the power supply has failed in my 4/330.
> > I'm still puzzled as to exactly what causes the size error for the P4 bus
> > write.  Like last time, we could try by trial and error, but it might be
> > an extended process.
> >
> > David's suggestion is good though - if you can check that it boots with an
> > earlier kernel, then we could look at the differences in the P4 bus setup,
> > which would give us a good starting point.
>
> I sent a reply to David yesterday but I accidentally sent it just to
> him and not the list, here it is below.
>
> 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 :)

> However this
> framebuffer works fine on sun3 so I believe it's something specific to
> sparc. Using printf() I found the line causing the panic is this.
>
> bt->bt_addr = 0;
>
> I've been scratching my head for a while now trying to figure out how
> and why this causes it. My only guess is that it only accepts 8 bit
> writes. But that would be rather odd as no other sun framebuffer had
> that limitation from what I can tell looking at the drivers. Not
> really sure where to go from here.

Does anyone have a SunOS dmesg to hand to confirm the address values
match those used by NetBSD?

Thanks

David