[alsa-devel] Problems with maintaining a separate alsa-driver in a distribution

[Takashi Iwai]

At Mon, 18 May 2009 13:33:10 +0300,
Ozan Çağlayan wrote:
> 
> Hi,
> 
> I'm maintaining the ALSA stack as a separate alsa-driver using the
> supplied tarballs from www.alsa-project.org unlike some popular distros
> which uses the in-kernel sound/ stack. This has the advantage of quickly
> acting against latest quirk or driver support changes and pushing a
> driver update instead of whole the kernel update.
> 
> But there is a big disadvantage that I'm not able to figure out how to
> solve:
> 
> When we enable the SND Kconfig option in kernel, some other sound
> support for some DVB devices(e.g. SAA7134 sound support, etc.) are
> enabled as well. So if you're using the in-kernel ALSA, you can enable
> and use them happily but in my case, those additional sound supports
> can't be enabled in kernel.
> 
> Is there a way to hack around this when a separate alsa-driver is used
> in a distro?

It's fairly difficult because the internal API was changed.
Especially the core struct was modified recently, thus there is no
ABI compatibility at all between the older kernel and the latest alsa
driver.

> Is it technically possible to patch those tiny drivers onto
> alsa-driver and compile them if the .config file from the kernel source
> has enabled those DVB devices?
>
> Or maybe I should enable ALSA in-kernel, compile those DVB sound stuff
> and remove the sound/ directory from the kernel package? (Even the idea
> sounds really *dirty*, dunno if it's technically possible too)

You'd need to copy the original ALSA in-kernel stuff, copy the headers
from alsa-driver, then rebuild the related modules in kernel to follow
the new API.  Also, some wrappers would be needed, e.g. for the
obsoleted snd_card_new().


Takashi