From: David Fries <david@fries.net>
Date: Fri, 25 Dec 2009 20:22:38 +0000 (-0600)
Subject: modem.conf Off-hook improve behavior
X-Git-Tag: v1.0.23~7
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=63acb8732933aa9732e3bf2e3affef925dd9c45b;p=alsa-lib.git

modem.conf Off-hook improve behavior

Only restore the old value if it differs from the requested
value, because if it has changed restoring the old value
overrides the change.  Take for example, a voice modem with
a .conf that sets preserve off-hook.  Start playback (on-hook
to off-hook), start record (off-hook to off-hook), stop
playback (off-hook to restore on-hook), stop record (on-hook
to restore off-hook), Clearly you don't want to leave the
modem "on the phone" now that there isn't any playback or
recording active.

Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

diff --git a/include/control.h b/include/control.h
index 29ea397e..3d6b0a5f 100644
--- a/include/control.h
+++ b/include/control.h
@@ -423,6 +423,7 @@ int snd_ctl_elem_value_malloc(snd_ctl_elem_value_t **ptr);
 void snd_ctl_elem_value_free(snd_ctl_elem_value_t *obj);
 void snd_ctl_elem_value_clear(snd_ctl_elem_value_t *obj);
 void snd_ctl_elem_value_copy(snd_ctl_elem_value_t *dst, const snd_ctl_elem_value_t *src);
+int snd_ctl_elem_value_compare(snd_ctl_elem_value_t *left, const snd_ctl_elem_value_t *right);
 void snd_ctl_elem_value_get_id(const snd_ctl_elem_value_t *obj, snd_ctl_elem_id_t *ptr);
 unsigned int snd_ctl_elem_value_get_numid(const snd_ctl_elem_value_t *obj);
 snd_ctl_elem_iface_t snd_ctl_elem_value_get_interface(const snd_ctl_elem_value_t *obj);
diff --git a/src/control/control.c b/src/control/control.c
index 51628ba8..b63a28cd 100644
--- a/src/control/control.c
+++ b/src/control/control.c
@@ -2248,6 +2248,18 @@ void snd_ctl_elem_value_copy(snd_ctl_elem_value_t *dst, const snd_ctl_elem_value
 	*dst = *src;
 }
 
+/**
+ * \brief compare one #snd_ctl_elem_value_t to another
+ * \param dst pointer to destination
+ * \param src pointer to source
+ * \return 0 on match, less than or greater than otherwise, see memcmp
+ */
+int snd_ctl_elem_value_compare(snd_ctl_elem_value_t *left, const snd_ctl_elem_value_t *right)
+{
+	assert(left && right);
+	return memcmp(left, right, sizeof(*left));
+}
+
 /**
  * \brief Get CTL element identifier of a CTL element id/value
  * \param obj CTL element id/value
diff --git a/src/control/setup.c b/src/control/setup.c
index 408244e2..eecda457 100644
--- a/src/control/setup.c
+++ b/src/control/setup.c
@@ -192,7 +192,17 @@ int snd_sctl_remove(snd_sctl_t *h)
 				return err;
 			}
 		}
-		if (elem->preserve) {
+		/* Only restore the old value if it differs from the requested
+		 * value, because if it has changed restoring the old value
+		 * overrides the change.  Take for example, a voice modem with
+		 * a .conf that sets preserve off-hook.  Start playback (on-hook
+		 * to off-hook), start record (off-hook to off-hook), stop
+		 * playback (off-hook to restore on-hook), stop record (on-hook
+		 * to restore off-hook), Clearly you don't want to leave the
+		 * modem "on the phone" now that there isn't any playback or
+		 * recording active.
+		 */
+		if (elem->preserve && snd_ctl_elem_value_compare(elem->val, elem->old)) {
 			err = snd_ctl_elem_write(h->ctl, elem->old);
 			if (err < 0) {
 				SNDERR("Cannot restore ctl elem");