[alsa-devel] [PATCH] ALSA: control: fix failure to return numerical ID in event data

[Takashi Iwai]

At Sun,  8 Feb 2015 19:28:56 +0900,
Takashi Sakamoto wrote:
> 
> Currently an instance of control has zero as its member for numerical
> ID even if any IDs are assigned to. According to this bug, any userspace
> applications cannot identify controls by the ID when handling any events.
> On the other hand, the other members such as name are still valid,
> therefore applications can identify controls without fixing this.
> 
> This is not preferable because the ID has an advantage to allow userspace
> applications to distinguish each controls by itself, without any
> combinations.
> 
> Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>

You're trying to address two individual bugs.  Please split.
The first bug is the missing zero clear of id.numid, and the second
bug is the missing numid set for notification.  Both can be oneliner.
The latter would be something like:

--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -371,7 +371,7 @@ int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 	}
 	list_add_tail(&kcontrol->list, &card->controls);
 	card->controls_count += kcontrol->count;
-	kcontrol->id.numid = card->last_numid + 1;
+	id.numid = kcontrol->id.numid = card->last_numid + 1;
 	card->last_numid += kcontrol->count;
 	count = kcontrol->count;
 	up_write(&card->controls_rwsem);

If you want to reorder the calls and add the comments, do it in
another patch to make clear that it's just a refactoring.  Don't mix
up refactoring and a fix, unless it's really trivial.


thanks,

Takashi