Re: audio usemixer breaks vs(4) Re: CVS commit: src/sys/dev

[Tetsuya Isaki <isaki%netbsd.org@localhost>]

At Wed, 8 Nov 2017 10:10:52 +1100,
Nathanial Sloss wrote:
> > With this change, vs(4) no longer works even if usemixer=0.
> > Please revert it, and don't break without public discussion.
> 
> vs audio with the mixer enabled has been fixed in a follow up commit.

Thank you for fixing.  But if you knew it would break something,
you should have asked it before commiting.

> The change was intended to benifit slow (antiquated) computers that may have 
> trouble with the extra code in the audio path with mixing enabled.

You should have discussed it before commiting.  There might
have been another solution or strategy.

> The reason as to why vs audio does not work with usemixer=0 is that you 
> decided to remove what you considered to be dead code (mulaw, alaw, unsigned 
> linear filters).

No, it was certainly a dead code at that time.  You had to
explain/discuss about such MI-MD destructive changes before you
did it.

In the old days, the MI-MD specification of set_params is
``mulaw is mandatory, others are optional.''
Last year, you imported in-kernel mixing and changed the spec to
``slinearNN_<HostEndian> is mandatory, others are never used''
without any explanation/discussion.  It broke some minor devices
which did not support slinear. [*]
Half a year ago, I noticed it and repaired vs(4) [**].  And I
deleted the code which is no longer used by your silent change.

Two days ago, you commited usemixer feature.  You changed the spec
to ``slinearNN_<HostEndian> is mandatory, others are optional''
without any explanation/discussion.
And you says that the reason was my deletion.

 *: At least one driver is still broken by this change.  Although
    there may be no users for the device :-)
 **: There was another MI-MD destructive change about slinear8.

> The time I've spent on audio/ossaudio/bluetooth audio has been at least two 
> years non-stop and I will devote more time to it in future - so I think it's 
> fair to say we've all spent a lot of time perfecting NetBSD.

You used your two years for youself.
I have not used this half a year for myself.

> Best regards and I hope to collaborate with you on audio in future as it is a 
> mutual interest.

Please go ahead.
I have no opinion anymore.
---
Tetsuya Isaki <isaki%pastel-flower.jp@localhost / isaki%NetBSD.org@localhost>