Re: bzImage boot trouble on Toshiba laptop

Hans Lermen (lermen@elserv.ffm.fgan.de)
Tue, 16 Jul 1996 16:39:38 +0200 (MET DST)


On Sun, 14 Jul 1996 jmaurer@cck.uni-kl.de wrote:

> I'm having problems booting bzImage type kernel images on a
> Toshiba Tecra 710CDT laptop. The computer resets itself right
> at the beginning of the boot sequence between displaying the
> final "Loading..." dot and the "Uncompressing..." message. If
> not interrupted, this leads to an endless booting loop. This
> error does not occur when using zImage type kernels or loadlin.
> [ ... ]
> My current theory on this is that the BIOS's INT15 handling code
> does something strange with the processor's protected mode.

Well, we (Werner Almesberger and me) have been reported some
similar effect with INT15 also on some other motherboards (desktop).
It turns out that data is either not correctly read from the disk
(DMA/IRQs happening while in INT15) or not correctly moved high.
Hence I don't believe that there is a protected mode oddness.
It faults just because there is garbage instead of code.
And the funny result of some investigation gave that turning off
the first level cache or inserting some waitstates made the error
disappear.
So I suspect this error to be either in the BIOS or the hardware or both,
and it is _very_ seldom.
Nevertheless we are searching for a workaround (no success till now).

However, all instancies of this error reported to us _could_ load
when using either Loadlin or raw-floppy-boot. As you say raw-floppy-boot
was showing the error for you, I'd like to have the following test to
insure that it _is_ the INT15:

Can you please boot from a pure MSDOS <= 6.2 disk (no Windows95) and force
Loadlin to use INT15 also ? ( NO device=emm386, NO device=himem.sys )
If this also fails, we have isolated the problem a bit.

Hans
<lermen@fgan.de>

PS: Starting next week I'm on vacation, so if you get no answer from me
after this, you know why ;-)