Re: SOLVED = RE: Alsa & 2.6 kernel

[Takashi Iwai <tiwai@suse.de>]

At Thu, 25 Sep 2003 11:27:04 -0700,
Mark Knecht wrote:
> 
> > >
> > >    Does this sound about right? I may try it out one of these days.
> >
> > yes.  alsa-kernel tree includes the all files (including Kconfig)
> > except for OSS driver codes under oss directory.
> 
> Oops! I thought I was clear up to this, so I want to double, double check.
> When you say 'OSS driver codes' here, you are speaking of the real OSS that
> is not part of Alsa, correct? I have not ever built (TTBOMK) real OSS Sound
> support, and don't want to do so now. I do want 'OSS Emulation' that is
> offered by Alsa. I get this from the Alsa code and not from anything in the
> OSS directory, correct?

right.

 * linux/sound/oss = the old good real OSS drivers, which was located
                     at linux/drivers/sound on 2.4 tree.
                     (i mean here OSS is not genuine OSS by 4front but
                      so-called OSS/Free or OSS/Kernel.)

 * linux/sound/core/oss = ALSA OSS emulation modules, namely,
                     snd-pcm-oss and snd-mixer-oss modules.

in addition, in linux/sound directory, you'll find two files which
were originally in linux/drivers/sound on 2.4 kernel: sound_core.c and
sound_firmware.c.  since these files are the common base for both ALSA
and OSS, they are put there.  and they can be found in alsa-kernel
tree, too, indeed.

> The right answer (in my mind) is that I should be able to delete the oss
> directory in linux/sound, not enable OSS Sound support when I configure the
> kernel, and still get OSS emulation support from Alsa. I hope I have not
> been incorrect about this.

oh, don't remove the contents under linux/sound/oss.  since the kernel
configurator needs the files (at least linux/sound/oss/Kconfig), you
should keep them as they are.

> >
> > please remember the difference of alsa-kernel and alsa-driver trees.
> > for 2.6.x kernel, only alsa-kernel tree is used.
> 
> Right! The 'drivers' portion of the 2.4 series kernel is now located in
> /linux/sound. I see my hdsp.c driver under pci. If I needed to do an HDSP
> 9652 update, I would take Thomas's work and place it in the
> linux/sound/pci/rme9652 directory and rebuild the kernel and kernel modules.
> 
> >
> > also, you can build on alsa-drivers as well as 2.4.x (i fixed this
> > yesterday).  but in this case, note that the kernel configuration will
> > override the local configuration of alsa-driver (provided by configure
> > script).
> > for example, if you turn off the ALSA support on 2.6.x kernel config,
> > you cannot build on alsa-drivers tree properly at all.
> > this causes often problems when CONFIG_SND_DEBUG mismatches between
> > kernel and alsa-driver trees.
> 
> Certainly. Of course, I'm not a programmer, but I cannot understand why and
> end-user like me would want to turn off Alsa support in the kernel but still
> build a driver. I'm trying to be a good citizen. Just give me Alsa and my
> driver and I'll be happy! ;-)

:)

well, if you want to try an experimental driver on 2.6, too, you'll
need build alsa-drivers tree.  as long as you need only the drivers
already existing on linux kernel tree, this is not necessary.


HTH.

ciao,

Takashi


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