Re: Powerbook shuts down hard when hot, patch found

On Saturday 29 September 2007 01:04:13 Benjamin Herrenschmidt wrote:

On Fri, 2007-09-28 at 23:32 +0200, Michael Buesch wrote:

quoted

Hi,

some time ago I already mailed you about this problem.
I will quickly describe what's going on, again:

My powerbook boots fine when it's cold. You can work with
it and you can also run it hot (compile something, etc...).
But when you try to boot it while it is hot, it will
automatically shutdown hard inside of the boot process.
Some part of the hardware is shutting it down.
This does not happen when it's getting hot _after_ boot.
Only while boot when it's hot.

I bisected the problem and found out that the following patch
is responsible for this. Yeah, this sounds a little bit
crazy, as this patch does not seem to be related to
this at all. But I confirmed it by booting kernel
4f71c5de19c27f2198105d3b26b398494d5c353b
That kernel triggered the bug. Then I patch -R the patch below
and it booted properly, even when hot. I also rechecked
that it really was hot enough to trigger the event by
immediately rebooting into a known bad kernel, that immediately
shut down the pbook, as expected.
So I'm pretty sure it's the patch below causing this weird
behaviour. Any idea why?

This is very strange... Can you try also clearing VGA_DDC_CLK_OUT_EN and
VGA_DDC_DATA_OUT_EN and the same time and see if that helps ?

It still triggers the bug then.

-- 
Greetings Michael.