[alsa-devel] [RFC] alsa-kernel clean-ups

John Utz john.utz at dmx.com
Thu Dec 20 21:33:49 CET 2007

Please Do!

On Thu, 20 Dec 2007 15:55:56 +0100
"Takashi Iwai" <tiwai at suse.de> wrote:

> Hi,
> ALSA kernel tree has lots of unused and rotten codes.  I'd like to
> clean up this.  Here we go...
> 1. Indirect control element access
>   This is what I already suggested.  This hasn't been used (we have no
>   proper API in alsa-lib), and 32/64bit wrapper doesn't work at all.
>   Also, the idea to copy such a big data area via ioctl is bad.  If we
>   need a big matrix mixer, let make each matrix element accessible
>   individually.  Copying the whole matrix at each time isn't
>   efficient.
> 2. PCM xfer_align parameter
>   This sw_params parameter has never been used in a sane manner, and
>   no one understands what this does exactly.  The current
>   implementation looks also buggy because it allows write of shorter
>   size than xfer_align.  So, if you do partial writes, the write isn't
>   actually aligned at all.
>   Removing this parameter will make some pcm_lib_* code more readable
>   (and less buggy).
> 3. PCM sleep_min and tick
>   The "tick" in PCM is set (again) via sw_params.  And, nobody uses
>   this feature at all except for a command line option of aplay.
>   (This is literally "nobody", as I checked alsa-lib API calls in all
>   programs in some major distros.)
>   Above all, if we need finer wake-ups for the position update, it's
>   basically an issue that the driver should solve, not tuned by each
>   application.
> 4. sound/driver.h
>   This header file exists only for some hacks to adapt alsa-driver
>   tree.  It's useless for building in the kernel.  Let's move a few
>   lines in it to sound/core.h and remove it.
>   For building the modules on alsa-driver external tree, we can simply
>   add
>     #include "adriver.h"
>   to each build stub (alsa-driver/*/*.c) before inclusion of
>   alsa-kernel codes.
> I'll post some patches to clean the above thing up in the following
> posts.  Please speak up if you have objections.
> Takashi
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