[svlug] mk_initrd works with one kernel but not with another

[Ivan Sergio Borgonovo]

I finally compiled a decent SMP kernel for my machine and I was going to 
solve some, I hope, minor problem with the sound board (SB16 PnP).

I've read ALSA docs and I was trying to built a kernel accordingly to what is 
suggested... compilation was OK but last step when I tried to create initrd 
with SuSE script failed with "unable to mount" error.

I went back to single CPU backup kernel... I did mk_initrd and I succeded.

Since 2 CPU compile the kernel faster I would like to know what could be 
wrong in the kernel setup for SMP.

I think it is something related to RAM disks support and initrd support 
switches in the Block device section of new kernel.
They were set ON in the new kernel but no loopback support.

Suspect lines of the mk_initrd are:

mount -oloop $tmp_initrd $tmp_mnt 2>/dev/null || { 
      if [ -f /lib/loop.o ] ; then
        insmod /lib/loop.o
        mount -oloop $tmp_initrd $tmp_mnt 2>/dev/null || {
          error 3 "failed to mount image"
        }
      else
        error 3 "failed to mount image"
      fi
    }
    is_mounted=1

Should I enable RAM disks support and initrd support?
or maybe I should enable loopback device support?
or both?

BTW teorethical interest...
1) what are the pros/cons of using ALSA inspite of modules provided in the 
kernel?
2) how can I check what were the config option of compiled kernel if I don't 
have the config file? I would like to know more than the output of lsmod

TIA