On Thu, 12 Nov 2009, Takashi Iwai wrote:
At Thu, 12 Nov 2009 11:39:12 +0100, I wrote:
At Thu, 12 Nov 2009 10:54:02 +0100 (CET), noreply-git@alsa-project.org wrote:
commit 6739046df36c7adf80c961bcba4870270e66dbf6 Author: Jaroslav Kysela perex@perex.cz AuthorDate: Thu Nov 12 10:15:48 2009 +0100 Commit: Jaroslav Kysela perex@perex.cz CommitDate: Thu Nov 12 10:51:48 2009 +0100
ALSA: hda - proc - add support for dynamic controls to mixer<->NID mapping This patch adds support for dynamically created controls to proc codec file (Control: lines). Signed-off-by: Jaroslav Kysela <perex@perex.cz>commit c45b73bf328cd8ace53cf39994328cf9d6548c4f Author: Jaroslav Kysela perex@perex.cz AuthorDate: Wed Nov 11 13:43:01 2009 +0100 Commit: Jaroslav Kysela perex@perex.cz CommitDate: Thu Nov 12 10:51:16 2009 +0100
ALSA: hda - proc - introduce Control: lines to show mixer<->NID assignment This is an initial patch to show universal control<->NID assigment in proc codec file. The change helps to debug codec related problems. Signed-off-by: Jaroslav Kysela <perex@perex.cz>I find the second one is the nice hack, but the first (newer) one isn't good since it abuses the subdevice field of the ctl id. It is a part of API/ABI, and if we do any changes the semantics, we should define the changed behavior *beforehand* publicly.
BTW, I don't mean that using subdevice is wrong. Instead: if we use it, let's define the proper definition first. For example, define (1 << 31) as the private (driver-specific) field bit in control.h.
Actually, using the subdevice can make the change of snd_hda_add_ctl easier, too. Then you don't keep nid in another field but just use snd_kcontrol to retrieve the nid.
Of course, we'd need to check the existing apps (at least our own) whether subdevice is really safe to change freely, though.
I think that you overlooked this code in snd_hda_add_new_ctls():
if (knew->subdevice & (1<<31)) { nid = knew->subdevice & 0xffff; kctl->id.subdevice = 0; } else { nid = 0; }
The subdevice value for nid contents will never leave the HDA code.
Jaroslav
----- Jaroslav Kysela perex@perex.cz Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc.