Hi again
Just some feedback - it seems that I have isolated the problem below with the
help of a 2005 post by John Nielsen to freebsd-questions
(http://lists.freebsd.org/pipermail/freebsd-sparc64/2005-August/003423.html).
I have isolated the problem as being caused by the compiler optimization flags,
specifically the "-O2 -pipe" flags (the default flags used when "makeoptions
DEBUG=-g" is not specified in the kernel configuration). I have proved that
the DEBUG flag per se has nothing to do with it by removing it, and then adding
makeoptions COPTFLAGS="-O -pipe" to the kernel config. This boots fine.
Funny though, the exact original kernel used (without DEBUG and compiled with
-O2) works fine on other hardware (e.g. the Tyan Tank G20 B5211 motherboard
with an Intel Core2Duo CPU). It only fails on the WADE-8020 board. It must be
some specific hardware driver used on the WADE-8020 motherboard that breaks
when compiled with -O2.
If anyone has suggestions as to how I can trace the problem further (so that I
can log a bug with the BSD community), this will be appreciated. Hopefully I
can ensure that a future user does not struggle with the same problem I did.
As always, thanks for the help.
Regards,
Dirk Kotze
Developer
> From: Dirk Kotze
> Sent: Monday, January 23, 2012 4:27 PM
> To: 'freebsd-questions@freebsd.org'
> Subject: Makeopts DEBUG=-g kernel option
>
> Hi there
>
> I'm experiencing the following problem: All is well when I boot the standard
> FreeBSD 8.2 GENERIC kernel. The moment
> however when I comment out the line the line below, the kernel hangs upon
> boot after detecting the em0 device (the
> motherboard has 2 Intel 8257x dual Gigabit Ethernet cards).
> makeopts DEBUG=-g
>
> I'm using FreeBSD 8.2 on a WADE-8020 motherboard with an Intel QM57 chipset
> and Intel Core i5 CPU.
>
> The reason I'm trying to remove debugging options from the kernel is that I
> am trying to make the kernel footprint
> smaller.
>
> This leaves me with a few questions:
> 1) What are the risks/drawbacks/advantages of leaving debugging symbols in
> the kernel?
> 2) Why would debug symbols (of all things!) make the difference between a
> working and non-working kernel?
> 3) Does this point in the direction of some other (more serious problem
> perhaps?) with the hardware and/or other
> kernel drivers?
>
> Thanks so much for any assistance.
>
> Regards,
> Dirk Kotze
> Developer
>
>
> Tel: +27 12 672 7281
> Fax: +27 12 665 1343
> Postal: P.O. Box 7991, Centurion, 0046
> Physical: 1 Pieter street, Highveld Park, Centurion
>
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