[alsa-devel] [PATCH] Palm interrupt driven touchscreen driver

[Takashi Iwai]

At Thu, 4 Jun 2009 11:38:07 +0100,
Mark Brown wrote:
> 
> On Thu, Jun 04, 2009 at 11:44:22AM +0200, Takashi Iwai wrote:
> > Mark Brown wrote:
> 
> > > There was a very strong pushback against the idea of adding a void *
> > > to the structure, which is what I'd be looking for.
> 
> > Yes, I was against the void pointer because there is no guarantee
> > of the data-type correctness between the data and the user.
> > The normal drvdata is fine because the creator and the user are the
> > same.  But, the proposal of private_driver_data (of the last one, at
> > least) is no such a scenario.
> 
> Do you have a pointer to this proposal?  I don't remember it and my
> google-fu is weak today.

I couldn't find it.  But IIRC, the original patch was to add "int irq"
field to struct snd_ac97.  I would accept it because it can do any
harm.

But, adding a generic "void *driver_data" instead of "int irq" can
play a bad game.  It can be dangerous when the creator and the user of
this pointer are different drivers.  That was my argument.


thanks,

Takashi