Debugging device drivers

[Francis Gudin]

Hi all,

i'm trying to understand why my SB16 soundcard isn't recognized by
DragonFly, though working alright under FBSD 5.4: i already had a
long-standing problem with ips(4) and as i've got no other controller to
boot from, i had to go through a painful cycle (put printf everywhere,
rebuild on another host, scp & install the new kernel, reboot, try
to understand anything at all...).

As a sound card isn't that critical to the boot process, i'd like to
know if an easier way of debugging exists: would it be possible to
build a kernel without any sound support, instrument and somewhat
hack bits of snd_sbc and friends and then use kldload/kldunload to
investigate ? I mean: will the probe routines get called as they would
during normal kernel initialization ?

Thanks for any tips,
Francis.

PS: though the device names changed a little bit in kernel config files
between FBSD and DFly, i'm still using the same parameters in both case
(same irq, port, etc.)