FreeBSD Handbook: Soundcard Setup Addition (7.2.1)

[Pyun YongHyeon]

On Mon, Jun 06, 2005 at 08:51:00AM -0500, Matthew D. Fuller wrote:
 > On Mon, Jun 06, 2005 at 09:44:59AM -0400 I heard the voice of
 > Mathew Kanner, and lo! it spake thus:
 > > 
 > > It will only show 'kld blah' if it is a kernel loaded module.
 > 
 > I'm pretty sure it didn't have it when I was KLD'ing around (and who
 > the heck would guess that "Microsoft Sound System" would be the driver
 > for Crystal Semiconductor?).  I could be remembering wrong, since that
 > was a while ago, but I'm pretty sure I wouldn't have spent all that
 > time loading and unloading drivers to figure out which it was, if
 > it'd'a told me...
 > 

AFAIK mss(4) is generic driver that supports many audio cards including
onboard one. Yes it's not ideal one. In theory we should have a
common chipset support code and should have probing routine for each
bus(PCI, ISA, SBus, EBus etc). However many parts of ISA soundcard
code prevents this from happening. In addition, all audio drivers have
implicit ISADMA dependency which is not needed at all for systems
that does not have ISA bus(e.g. sparc64)
Removing ISA dependency is hard since many old-cheap PCI audiocards
assume ISADMA cycles on PCI bus and needs SoundBlaster compatible
I/O operations when it runs at capturing mode. :-(

It seems that it would be better to make snd_mss(4) document out of
pcm(4) document.

-- 
Regards,
Pyun YongHyeon
http://www.kr.freebsd.org/~yongari	|	yongari at freebsd.org