Re: [PATCH RFC 0/7] Allow multiple callbacks for hda_jack

[Takashi Iwai <tiwai@suse.de>]

At Mon, 15 Sep 2014 10:42:21 +0200,
Takashi Iwai wrote:
> 
> At Thu, 11 Sep 2014 17:14:00 +0200,
> David Henningsson wrote:
> > 
> > 
> > 
> > On 2014-09-11 16:19, Takashi Iwai wrote:
> > > Hi,
> > >
> > > this is a series of patches I quickly cooked up after the discussion
> > > in this morning: the support of multiple callbacks per jack.
> > >
> > > The series is applied on top of the previous fix patch (ALSA: hda -
> > > Fix invalid pin powermap without jack detection).  It begins with
> > > a couple of cleanups, then introduces the new hda_jack_callback
> > > struct and the changes along with it, then ends with another
> > > couple of cleanup patches based on the new infrastructure.
> > >
> > > I've tested only with a small set of devices, so far.
> > 
> > In general I like this idea and I remember thinking along the same lines.
> > 
> > I'm pondering whether we could use a more memory efficient layout for 
> > the callback list. Like allocating a snd_array on codec level and have 
> > indices to that list instead of pointers. Then the kernel would have 
> > less memory blocks to worry about. What do you think?
> 
> I don't think the memory usage would be any problem in this case as
> it's just a few numbers of small blocks.  The only question is which
> is better manageable in the source code level.  Let's see...

I tried hacking with snd_array, but this ended up more complexity in
the code (either adding an extra stuff into struct hda_codec or
obviously more overhead than the simple kmalloc).  So, I decided to
keep the code as it was.

If you find a better solution, let me know.  In anyway, I'll submit v2
patches.


thanks,

Takashi