Going from 2.2.12 to 2.2.17pre10

[Gabriel Paubert]

On 7 Jul 2000, Michael Lundkvist wrote:

> I have to be able to create a standalone system so network boot is not
> an option.

Sigh, and falshing the kernel neither I suppose...

> Maybe I'll look in to creating a driver for the bootloader. When I get
> some spare time....

> How portable is something like Grub? Maybe that could be a way to go.

I was under the impression that it was very x86 focussed (but maybe I'm
mixing things up with OpenBIOS).

> > Note that thiss was for 2.2.12, as I said I've not booted 2.2.16 so I did
> > not put the patches on my ftp site (that's the only QA I do :-)).
> >
>
> OK. 2.2.12 is not interesting. I don't want do reinstall again... :)

Fine, but 2.2.16 is claimed to have other problems (look at Alan's release
notes for each 2.2.17-pre).

> I have tried two MVME-2400 boards but I haven't had time to do any
> systematic testing. It always crashes in find_buffer in fs/buffer.c
> during moderate to heavy disk activity. I'm starting to suspect that
> the CMD646 isn't being setup correctly since it feels like the system
> was more stable after a cold reboot. I'll have to test it a bit more.

Ok, that's likely the cause. SCSI (NCR) disk access is rock solid here on
MVME2600.

> You're probably right that it's easier modify the backplane.

No, it's not the backplane, it's the implementation in the MVME boards:


PCI bus <-> Universe <-> Layer of buffers <-> VME connectors

The PCI bus is probably largely buried inside the PCB layers.
The Universe is a BGA.
The VME bus has only one (bidirectional) reset signal.

However there are 2 VME reset signal buffer, one inwards and one outwards
for 2 pins of the Universe (VME reset in and VME reset out).

	Universe       Buffers       VME connector

	VXSYSRST-------|>o--+
                            |--------SYSRST*
	VRSYSRST#------<|---+

The only accessible place (with adequate lab equipment) are the buffers:
cut the input or the output of the receive buffer and connect it to the
power supply (safer on the input since it can directly be connected to
the buffer power supply while I'm not sure that some versions of the
Universe are not 3.3V only)   .

	Gabriel.


** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/