Re: [patch, -git] media/video/sound build fix, TEA5761/TEA5767

[Takashi Iwai <tiwai@suse.de>]

At Wed, 30 Apr 2008 04:17:03 -0700 (PDT),
David Miller wrote:
> 
> From: Takashi Iwai <tiwai@suse.de>
> Date: Wed, 30 Apr 2008 13:11:31 +0200
> 
> > IMO, it's the reverse selection from sound to V4L that makes things
> > complicated.  I believe it's better to fix it as a normal dependency.
> > 
> > How about the patch below?
> 
> The question that remains is what does this mean for users?
> 
> How does a user, who wants to enable this 'sound' driver,
> learn that they must enable the v4l subsystem in order to
> do so?
> 
> This is typically why select constructs are used, to not bother the
> user with such messy details.

Yes, from the usability POV, select is better.

> But like we see in this case, it can cause serious implementation
> problems if not used properly. :(

Indeed.  The problem is that the select doesn't (can't?) resolve the
dependecy in a reverse way.  For example, select VIDEO_V4L1 won't turn
on the dependent items such as VIDEO_DEV, VIDEO_V4L2_COMMON,
VIDEO_ALLOW_V4L1, so and so.

Thus, when another dependency is added to the selected target, it can
easily break the depdency chain like this case...


Takashi