Fix for Section 7.2.1.1 - Soundblaster 16 driver

[Fred Wheeler]

Section "7.2.1.1 Configuring a Custom Kernel with Sound Support" of
the online handbook contains this text:

> Non-PnP ISA cards may require you to provide the kernel with
> information on the sound card settings (IRQ, I/O port, etc). This is
> done via the /boot/device.hints file. At system boot, the loader(8)
> will read this file and pass the settings to the kernel. For example,
> an old Creative SoundBlaster 16 ISA non-PnP card will use the
> snd_sbc(4) driver, with the following line added to the kernel
> configuration file:
> 
> device snd_sbc
> 
> as well as the following in /boot/device.hints:
> 
> hint.sbc.0.at="isa"
> hint.sbc.0.port="0x220"
> hint.sbc.0.irq="5"
> hint.sbc.0.drq="1"
> hint.sbc.0.flags="0x15"
> 
> In this case, the card uses the 0x220 I/O port and the IRQ 5.

I think this is slightly misleading and I have a fix.  

I just used the handbook to help get FreeBSD recognizing an old
Creative SoundBlaster 16 ISA non-PnP card.  I have found that drivers
other than "snd_sbc" are needed.  I found that I needed to put

  device snd_driver

in the /boot/kernel.conf file to include all the sound drivers and
also keep the above section in /boot/device.hints.  So, some driver
other than snd_sbc is needed for this card, though I'm not sure
exactly which.  Maybe more than one is needed.  Even though this part
of the handbook just uses the SB16 as an example for general sound
configuration, I was mislead by it.  I think it would be helpful to
add the following after the "In this case, the card uses the 0x220
..." line.

  With the SoundBlaster 16 it may be the case that other drivers, in
  addition to snd_sbc are needed.  If the above does not work, try
  putting "device snd_driver" in /boot/kernel.conf along with the
  above lines in the /boot/device.hints file.

Regards,
Fred Wheeler