Re: patch driver-core-warn-about-duplicate-driver-names-on-the-same-bus.patch added to gregkh-2.6 tree

Takashi Iwai
2008-04-30T06:34:50Z

At Tue, 29 Apr 2008 23:28:42 +0400,
Stas Sergeev wrote:
>
> Hello.
>
> Takashi Iwai wrote:
> > Though, I think the snd-pcsp driver could be better built on the top
> > of input pcspkr driver, or coexist with it. Then we'll have no more
> > conflict about platform name space.
> I was trying this in the past.
> This never worked out very well.

Why?

> I disliked the dependancies.
> Either snd-pcsp was loading pcspkr,
> or there had to be the global variable
> to prevent the concurrent access, and
> that hurts modularity.

But you anyway enable the input pcspkr feature in your snd-pcsp code.
So, basically you depend on (or build on) it.

> > When you compare input pcspkr.c and sound pcsp_input.c, you can find
> > that most of codes are identical.
> Yep, its a copy/paste mainly.
> I wanted a complete replacement.
> Back then, I've been told that multiple
> drivers controlling the same device is
> never a good idea. But I won't be surprised
> if that have changed since. :)
>
> > What we'd need is a hook on
> > pcspkr.c that adds a dynamic check whether snd-pcsp (or any ohter)
> > is running.
> How?

What you need is a way to check whether input pcspkr can be usable or
not. You can add a function pointer, for example.

> And also, with snd-pcsp you have a
> mixer control to disable the beeps,
> which I find sometimes even more
> usefull than the pcm sound itself. :)

Yes, that seems useful.

Takashi