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 29ea397..3d6b0a5 100644 (file)
--- 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 51628ba..b63a28c 100644 (file)
--- a/src/control/control.c
+++ b/src/control/control.c
@@ -2249,6 +2249,18 @@ void snd_ctl_elem_value_copy(snd_ctl_elem_value_t *dst, const snd_ctl_elem_value
 }
 
 /**
+ * \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
  * \param ptr Pointer to returned CTL element identifier

diff --git a/src/control/setup.c b/src/control/setup.c
index 408244e..eecda45 100644 (file)
--- 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");