File alsa-lib-ext-ctl-numid-fix.diff of Package alsa

From 81241ffb8176bde284699e5839bb944db39c773c Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 17 Feb 2009 16:58:12 +0100
Subject: [PATCH] Change numid properly with external ctl plugins

So far, external ctl plugins don't change numid.  Some apps expect the
non-zero numids with list, and the plugin doesn't work for them.

This patch adds a fake numid to each control based on the offset
number.  The lookup with non-zero numid is supported but is pretty
inefficient.  Eventually the plugin side may be optimized to look
at the numid, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 src/control/control_ext.c |   18 +++++++++++++++---
 1 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/control/control_ext.c b/src/control/control_ext.c
index a8675c1..d1fe8ea 100644
--- a/src/control/control_ext.c
+++ b/src/control/control_ext.c
@@ -107,6 +107,7 @@ static int snd_ctl_ext_elem_list(snd_ctl_t *handle, snd_ctl_elem_list_t *list)
 		ret = ext->callback->elem_list(ext, offset, ids);
 		if (ret < 0)
 			return ret;
+		ids->numid = offset + 1; /* fake number */
 		list->used++;
 		offset++;
 		ids++;
@@ -114,13 +115,24 @@ static int snd_ctl_ext_elem_list(snd_ctl_t *handle, snd_ctl_elem_list_t *list)
 	return 0;
 }
 
+static snd_ctl_ext_key_t get_elem(snd_ctl_ext_t *ext, snd_ctl_elem_id_t *id)
+{
+	int numid = id->numid;
+	if (numid > 0) {
+		ext->callback->elem_list(ext, numid - 1, id);
+		id->numid = numid;
+	} else
+		id->numid = 0;
+	return ext->callback->find_elem(ext, id);
+}
+
 static int snd_ctl_ext_elem_info(snd_ctl_t *handle, snd_ctl_elem_info_t *info)
 {
 	snd_ctl_ext_t *ext = handle->private_data;
 	snd_ctl_ext_key_t key;
 	int type, ret;
 
-	key = ext->callback->find_elem(ext, &info->id);
+	key = get_elem(ext, &info->id);
 	if (key == SND_CTL_EXT_KEY_NOT_FOUND)
 		return -ENOENT;
 	ret = ext->callback->get_attribute(ext, key, &type, &info->access, &info->count);
@@ -200,7 +212,7 @@ static int snd_ctl_ext_elem_read(snd_ctl_t *handle, snd_ctl_elem_value_t *contro
 	int type, ret;
 	unsigned int access, count;
 
-	key = ext->callback->find_elem(ext, &control->id);
+	key = get_elem(ext, &control->id);
 	if (key == SND_CTL_EXT_KEY_NOT_FOUND)
 		return -ENOENT;
 	ret = ext->callback->get_attribute(ext, key, &type, &access, &count);
@@ -254,7 +266,7 @@ static int snd_ctl_ext_elem_write(snd_ctl_t *handle, snd_ctl_elem_value_t *contr
 	int type, ret;
 	unsigned int access, count;
 
-	key = ext->callback->find_elem(ext, &control->id);
+	key = get_elem(ext, &control->id);
 	if (key == SND_CTL_EXT_KEY_NOT_FOUND)
 		return -ENOENT;
 	ret = ext->callback->get_attribute(ext, key, &type, &access, &count);
-- 
1.6.1.3