Fwd: Macintosh Quadra 950 Not Booting
On Fri, Aug 7, 2015 at 12:43 AM, Finn Thain <fthain@telegraphics.com.au>
wrote:
>
> On Thu, 6 Aug 2015, Greg Andrzejewski wrote:
>
> > Greetings,
> >
> > After finally getting my Mac SE/30 working again, I set about trying to
> > get a modern version of Linux installed on the little fellow. Early
> > experiments with 3.14 kernels were successful
>
> BTW, are you using mac_scsi on the SE/30?
>
I've just been grabbing kernel images from the Debian ports archive, so I
think so. 3.14 kernels would panic with a bus error on bootup unless I
disabled pseudo DMA, but I'm thinking that might be a hardware issue with
my machine. I had to solder a few jumper wires on the motherboard to repair
damage from leaking capacitors around the video/audio circuitry. Never
really had any problems with SCSI in MacOS, but I cleaned a lot of
capacitor goo from around the NCR chip, so sometimes I wonder. Linux gets
very upset if I have anything attached to the external SCSI port and MacOS
bombed out yesterday copying files to a zip disk, so it's probably
something I'm going to need to address in the future.
FWIW, the pseudo DMA problems have gone away for me in the 4.0 kernels, by
which I mean I no longer have to pass mac5380=-1,-1,-1,-1,0 on the command
line. I've been meaning to check if there was a fix or if pseudo DMA is
just disabled by default now.
> > and when a trio of Quadra 950s appeared on the local craigslist, I
> > picked them up, looking forward to a more powerful 68k machine. Problem
> > is I can't get any recent kernel to boot.
>
> I haven't booted a Q950 for some years, but it should work.
>
> Using Penguin, I did boot Linux 3.1 on a Quadra 700 which is somewhat
> similar hardware. The only other report I found on the list about a Q950
> was for Linux 2.6.20.
>
> If you would like, I can send you a current kernel binary that should boot
> any Mac (that is, SE/30 or Quadra 950).
>
Yeah, that'd be great. I think the most recent kernel I was able to boot
was 2.6.29 or something that I found online.
>
> Also, any debian kernel binary from 3.x or 4.x should give useful results.
> (Kernel modules aren't relevant to isolating the cause of an early crash.)
>
> >
> > I've tried using Penguin-19 on MacOS 7.1 and 7.5.3 with identical
> > results; the machine just hangs on the "Bootling Linux" message. The
> > screen never clears, nothing even comes across the serial port with
> > earlyprintk.
>
> Penguin has a known bug in its zlib code that can cause kernel
> decompression to fail like that. Is this a large debian kernel binary?
>
> I suggest you try booting the vmlinux, e.g.
> # gzip -dc < vmlinuz > vmlinux
> I use Penguin with MacOS 7.5.3 without any issues; however, you might want
> to try with extensions disabled (hold down <shift> when you hear the
> chime) to avoid a possible unhandled slot interrupt during early boot.
>
Just tried with decompressed kernel from the debian ports repository and
extensions disabled. Same behavior :-(
> I installed MacsBug in hopes of finding something useful in __log_buf on
> > reboot, but the entire buffer is empty (zeros). I'd suspect the
> > bootloader is at fault, but Penguin successfully boots a 4.0.0 kernel on
> > my SE/30. Penguin log is attached, in case anyone's interested.
>
> I don't know anything about __log_buf. I suspect you'd need to avoid the
> POST memory test for that to work.
>
Yeah, I was concerned about that, too. I think the best you can do to
preserve memory contents is to hold down <Ctrl> at the happy mac, which
invokes MacsBug at its earliest convenience. Other variables in the
neighborhood seem to have survived (log_buf and log_buf_len both have
correct values). Maybe I could try initializing the buffer with some
pattern and seeing if that survives a reboot.
>
> >
> > Still not 100% confident in Penguin, I tried booting with an EMILE
> > rescue disk. EMILE reads the kernel from disk and shortly thereafter the
> > chimes of death play (!!!!). Is this something the kernel can
> > intentionally do or is it more likely sort sort of triple fault-like
> > situation?
>
> I've never tried EMILE on my Q950. Perhaps Laurent can speak to that.
>
The highlighting showing the current selection in the boot menu doesn't
display. Other than that, the rescue floppy seemed to work okay.
>
> >
> > I've done a touch of kernel debugging, but this was on x86 and never
> > this early in the boot process. What next steps can I take to further
> > debug this issue?
>
> The first thing you should see is the output from the early boot code:
> "ABCFGHIJK". If you don't see that then likely causes are an unhandled
> early interrupt or bootloader bug.
>
> However, it is also possible that a recent commit has messed up the OSS
> driver:
>
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/arch/m68k/mac?id=b24f670b7f5b2058b95370caa9f104b3cefb9f1d
> But this first appeared in v4.1, so it probably isn't relevant.
>
> > I've glanced at the early arch code, but all I really got out of it was
> > a few chuckles from the comments venting about Apple's, uh, peculiar
> > hardware design.
>
> I suspect that the resentment of kernel developers would have been minimal
> had Apple made more documentation public. Unlike the authors of those
> comments, I don't blame Apple engineers for its corporate policies.
>
> Finn
>
> >
> > Thanks,
> > Greg
> >
>
Thanks for the help,
Greg
Reply to: