audblst.drv found in some Sierra games (KQ6 floppy version for
instance) uses highly dangerous method of blaster detection, and
overall aproach to IRQ handling is racy. However audblst.drv from LSL6
or KQ6-CD are fine in this regard. Just copy it over and things should
work.

======================================================================
Here's what detection procedure looks like in pseudo-code:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
setup_sound_blaster ();
setup_dma ();
set_blaster_dma_length (1);
// after transfering said one byte SB should assert its IRQ line
start_dma ();
start_SB ();

irq_number = 0;

for (cx = 0; cx < 2048; ++cx)
  if (irq_number != 0)
    goto good_blaster;

goto bad_blaster;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

irq_handler_1: irq_number = 1; exit_irq;
irq_handler_2: irq_number = 2; exit_irq;
irq_handler_3: irq_number = 3; exit_irq;
...
etc
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

the problem with that is two fold:

a. if IRQ is asserted after start_SB but before assignment to irq_number
   we are toast (DMA is programmed in a single shot mode, so no further
   IRQs will be generated)

b. for loop is very tight and our chances in firing while it runs are
   very slim. needless to say if we assert IRQ after for loop completes
   code will already take bad_blaster path

Even after patching audblst.drv manually, it never quite worked correctly,
i guess similar races are scattered all around the code.