My SB Live! Experience w/ ALSA

[Jeremy Fowler]

Couple of things:

1. Gentoo by default uses the 0.9 ALSA drivers, which are currently considered a development 
release. You can use the older 0.5 drivers which have support for more sound cards/chips and 
generally considered more stable; but you have to specifically emerge them by version number. Note, 
the two releases are incompatible with each other. 

2. In order for packages to use the ALSA driver native API you have to enable it by adding the 
"alsa" flag to your USE variable and then recompiling those packages. OSS emulation will not be as 
good as straight OSS drivers, so this is probably why you experienced slower frame rates and 
various other problems.

> -----Original Message-----
> From: owner-kclug at marauder.illiana.net
> [mailto:owner-kclug at marauder.illiana.net]On Behalf Of Jason Clinton
> Sent: Monday, November 04, 2002 11:20 AM
> To: kclug at kclug.org
> Subject: My SB Live! Experience w/ ALSA
> 
> 
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> Though I'd share my recent experience with my soundcard (SoundBlaster 
> Live!) in
> case anyone else has the same questions.
> 
> I usually compile my kernel w/o modules as one big kernel customized to my
> hardware. I'd been using OSS for some time to drive my SB Live! but I decided
> that I'd give ALSA a whirl since I've seen so many install guides 
> pushing people
> towards it.
> 
> First thing I did was to recomplile my kernel using modules this 
> time. I'd never
> done this before so it took a recheck of the Gentoo install guide and I found
> that I only needed to select the items I wanted as modules in 
> menuconfig and then:
> 
> /usr/src/linux # make dep && make clean bzImage modules modules_install
> 
> First the new kernel is compiled with modules support and placed in
> arch/i386/bzImage. Then the modules are compiled and linked to each 
> other. Then
> they are installed to /lib/modules/2.4.19/kernel/drivers/sound/.
> 
> To make sure everything was successful, I decided to load the OSS modules as
> though I were not switching to ALSA. I edited /etc/modules.autoload and added
> the three required modules to the file at the end of the file on lines by
> themselves:
> 
> - ---------
> #Blahblahblaha Gentoo modules.autoload
> ...[ethernet drivers here]
> sound  #this is the OSS core
> ac97_codec #required for SB Live!
> emu10k1 #the model number of the SigmalTel chip that runs SB Live! Cards
> - ---------
> 
> ALSA required the build of sound support in the kernel. After it was 
> compiled, I
> mounted my /boot partition and copied from /usr/src/linux/arch/i385/bzImage to
> /boot/bzImage. I'm using grub so no need to run the lilo command. Rebooted.
> Started X. Played some games. Sound is okay.
> 
> Now, in Gentoo, installing ALSA requires only one command:
> 
> ~# emerge alsa-driver alsa-oss alsa-utils
> 
> After it downloaded and compiled, it installed itself to
> /lib/modules/2.4.19/kernel/drivers/sound/snd-* Where snd-* files are all the
> ALSA drivers.
> 
> I commented out the sound drivers I added to modules.autoload earlier 
> so that I
> can easily turn OSS back on later. According to the ALSA docs, the 
> only thing I
> needed to do now was to edit /etc/modules.d/alsa . This varries from card to
> card so I'll leave it up to the docs to describe this part. The one 
> thing I will
> mention, however, is that the 2.4.19 kernel apparently compiles what 
> used to be
> 'soundcore.o' as just 'sound.o' so I change all references to 'soundcore' to
> 'sound' to get OSS emulation working.
> 
> One more set of commands:
> 
> # rmmod sound ac_97codec emu10k1
> # update-modules
> # /etc/init.d/alsa start
> # rc-update add alsa default
> 
> The first command unloaded OSS, the second updated modules.conf from
> /etc/modules.d/alsa, the third started ALSA and loaded all the ALSA 
> modules and
> the fourth added ALSA to my boot sequence. That's it!
> 
> Now, once ALSA was working I discovered some major caveats. OSS 
> emulation takes
> a bit of overhead off of applications that are using sound so my framerate
> dropped ever so slightly in Quake3 and WineX games.
> 
> I have a full 4.1 suround speaker system attached to my sound card 
> and heretofor
> Dolby Digital movies in Xine have played in full surround sound if 
> 'o-gain' was
> turned all the way up in the OSS mixer. In ALSA, however, I could never get
> suround sound to work properly. The best I could manage was 2.1 
> stereo mirrored
> to 4.1 which just sn't the same.
> 
> After much twidling I descide to stumble back to the less complicated OSS:
> 
> # /etc/init.d/alsa stop
> # rc-update del alsa default
> # rm /etc/modules.d/alsa
> # modules-update
> # emerge unmerge alsa-driver alsa-utils alsa-oss
> 
> Then I just simply uncommented the OSS drivers in modules.autoload and
> everything went back to normal.
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