Re: [PATCH v4 2/5] ALSA: ctxfi: initialized snd_card

[Sudip Mukherjee]

On Tue, Sep 23, 2014 at 04:09:08PM +0200, Takashi Iwai wrote:
> At Tue, 23 Sep 2014 16:30:21 +0530,
> Sudip Mukherjee wrote:
> > 
> > initialized the reference of snd_card which was added to the various
> > structures through the previous patch of the series.
> > these references of snd_card will be used in a later patch to convert
> > the pr_* macros to dev_*
> > 
> > Signed-off-by: Sudip Mukherjee <sudip@xxxxxxxxxxxxxxx>
> > ---
> >  sound/pci/ctxfi/ctamixer.c | 2 ++
> >  sound/pci/ctxfi/ctatc.c    | 1 +
> >  sound/pci/ctxfi/ctdaio.c   | 1 +
> >  sound/pci/ctxfi/ctsrc.c    | 2 ++
> >  4 files changed, 6 insertions(+)
> > 
> > diff --git a/sound/pci/ctxfi/ctamixer.c b/sound/pci/ctxfi/ctamixer.c
> > index fed6e6a..dc89fad 100644
> > --- a/sound/pci/ctxfi/ctamixer.c
> > +++ b/sound/pci/ctxfi/ctamixer.c
> > @@ -314,6 +314,7 @@ int amixer_mgr_create(void *hw, struct amixer_mgr **ramixer_mgr)
> >  
> >  	amixer_mgr->get_amixer = get_amixer_rsc;
> >  	amixer_mgr->put_amixer = put_amixer_rsc;
> > +	amixer_mgr->card = ((struct hw *)hw)->card;
> 
> Overall the patches became obviously better now, but unfortunately
> we still see such rather stupid cast occasionally.  I guess you
> considered reducing these?
frankly speaking , i did not think to reduce that untill now that u mentioned it.
I was thinking it was there for a reason and will be used like the private_data,
but i was not able to think of any reason as everywhere it is struct hw.

thanks
sudip

> 
> Then start thinking from the scratch: why the cast is needed at all?
> It's because the driver uses the void pointer for hw objects.  Why?
> The driver author tried to separate the code abstraction, and thought
> to pass the arbitrary hw object.
> 
> Such abstraction would be good if really different objects are
> handled.  OTOH, in ctxfi case, we know that we deal with only a single
> hw type.  So, using void * for hw object is rather error-prone, and
> the code safety can be even improved by strict typing.
> 
> That said, replacing void * with struct hw * or such would make things
> not only easier but also safer.
> 
> BTW, the patch 5 is basically independent from the rest, and it's good
> enough, so I applied it now.  At the next respin, please drop that
> patch from your series.
> 
> 
> thanks,
> 
> Takashi
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