pulseaudio/0028-alsa-rewrite-mixer-open-close-cache-mixer-accesses-i.patch

From 3bd7c70c518d66707cbfde138ab7dcc505e463ac Mon Sep 17 00:00:00 2001
From: Jaroslav Kysela <perex@perex.cz>
Date: Sat, 7 Dec 2019 20:39:21 +0100
Subject: [PATCH] alsa: rewrite mixer open/close, cache mixer accesses in probe

The ALSA mixer can be opened multiple times (especially for UCM
in the probe). This adds a simple mixer cache to prevent
multiple open calls.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
---
 src/modules/alsa/alsa-mixer.c       | 19 ++++----
 src/modules/alsa/alsa-mixer.h       | 19 ++++++--
 src/modules/alsa/alsa-sink.c        | 21 ++++----
 src/modules/alsa/alsa-source.c      | 21 ++++----
 src/modules/alsa/alsa-ucm.c         | 66 ++++++++++----------------
 src/modules/alsa/alsa-ucm.h         |  1 +
 src/modules/alsa/alsa-util.c        | 95 +++++++++++++++++++------------------
 src/modules/alsa/alsa-util.h        |  6 ++-
 src/modules/alsa/module-alsa-card.c | 76 ++++++++++++++++++-----------
 9 files changed, 175 insertions(+), 149 deletions(-)

diff --git a/src/modules/alsa/alsa-mixer.c b/src/modules/alsa/alsa-mixer.c
index 7956371b604b..a3c998b654e9 100644
--- a/src/modules/alsa/alsa-mixer.c
+++ b/src/modules/alsa/alsa-mixer.c
@@ -147,13 +147,14 @@ static int alsa_id_decode(const char *src, char *name, int *index) {
     return 0;
 }
 
-pa_alsa_jack *pa_alsa_jack_new(pa_alsa_path *path, const char *name) {
+pa_alsa_jack *pa_alsa_jack_new(pa_alsa_path *path, const char *mixer_device_name, const char *name) {
     pa_alsa_jack *jack;
 
     pa_assert(name);
 
     jack = pa_xnew0(pa_alsa_jack, 1);
     jack->path = path;
+    jack->mixer_device_name = pa_xstrdup(mixer_device_name);
     jack->name = pa_xstrdup(name);
     jack->alsa_name = pa_sprintf_malloc("%s Jack", name);
     jack->state_unplugged = PA_AVAILABLE_NO;
@@ -172,6 +173,7 @@ void pa_alsa_jack_free(pa_alsa_jack *jack) {
 
     pa_xfree(jack->alsa_name);
     pa_xfree(jack->name);
+    pa_xfree(jack->mixer_device_name);
     pa_xfree(jack);
 }
 
@@ -1982,7 +1984,7 @@ static pa_alsa_jack* jack_get(pa_alsa_path *p, const char *section) {
         if (pa_streq(j->name, section))
             goto finish;
 
-    j = pa_alsa_jack_new(p, section);
+    j = pa_alsa_jack_new(p, NULL, section);
     PA_LLIST_INSERT_AFTER(pa_alsa_jack, p->jacks, p->last_jack, j);
 
 finish:
@@ -4160,7 +4162,8 @@ fail:
 }
 
 static void mapping_paths_probe(pa_alsa_mapping *m, pa_alsa_profile *profile,
-                                pa_alsa_direction_t direction, pa_hashmap *used_paths) {
+                                pa_alsa_direction_t direction, pa_hashmap *used_paths,
+                                pa_hashmap *mixers) {
 
     pa_alsa_path *p;
     void *state;
@@ -4185,7 +4188,7 @@ static void mapping_paths_probe(pa_alsa_mapping *m, pa_alsa_profile *profile,
 
     pa_assert(pcm_handle);
 
-    mixer_handle = pa_alsa_open_mixer_for_pcm(pcm_handle, NULL);
+    mixer_handle = pa_alsa_open_mixer_for_pcm(mixers, pcm_handle, true);
     if (!mixer_handle) {
         /* Cannot open mixer, remove all entries */
         pa_hashmap_remove_all(ps->paths);
@@ -4203,9 +4206,6 @@ static void mapping_paths_probe(pa_alsa_mapping *m, pa_alsa_profile *profile,
     path_set_condense(ps, mixer_handle);
     path_set_make_path_descriptions_unique(ps);
 
-    if (mixer_handle)
-        snd_mixer_close(mixer_handle);
-
     PA_HASHMAP_FOREACH(p, ps->paths, state)
         pa_hashmap_put(used_paths, p, p);
 
@@ -4785,6 +4785,7 @@ static void mapping_query_hw_device(pa_alsa_mapping *mapping, snd_pcm_t *pcm) {
 
 void pa_alsa_profile_set_probe(
         pa_alsa_profile_set *ps,
+        pa_hashmap *mixers,
         const char *dev_id,
         const pa_sample_spec *ss,
         unsigned default_n_fragments,
@@ -4914,14 +4915,14 @@ void pa_alsa_profile_set_probe(
             PA_IDXSET_FOREACH(m, p->output_mappings, idx)
                 if (m->output_pcm) {
                     found_output |= !p->fallback_output;
-                    mapping_paths_probe(m, p, PA_ALSA_DIRECTION_OUTPUT, used_paths);
+                    mapping_paths_probe(m, p, PA_ALSA_DIRECTION_OUTPUT, used_paths, mixers);
                 }
 
         if (p->input_mappings)
             PA_IDXSET_FOREACH(m, p->input_mappings, idx)
                 if (m->input_pcm) {
                     found_input |= !p->fallback_input;
-                    mapping_paths_probe(m, p, PA_ALSA_DIRECTION_INPUT, used_paths);
+                    mapping_paths_probe(m, p, PA_ALSA_DIRECTION_INPUT, used_paths, mixers);
                 }
     }
 
diff --git a/src/modules/alsa/alsa-mixer.h b/src/modules/alsa/alsa-mixer.h
index 7864a2c1252f..325b0c998b02 100644
--- a/src/modules/alsa/alsa-mixer.h
+++ b/src/modules/alsa/alsa-mixer.h
@@ -32,6 +32,7 @@
 #include <pulsecore/rtpoll.h>
 
 typedef struct pa_alsa_fdlist pa_alsa_fdlist;
+typedef struct pa_alsa_mixer pa_alsa_mixer;
 typedef struct pa_alsa_mixer_pdata pa_alsa_mixer_pdata;
 typedef struct pa_alsa_setting pa_alsa_setting;
 typedef struct pa_alsa_mixer_id pa_alsa_mixer_id;
@@ -98,6 +99,13 @@ struct pa_alsa_setting {
     unsigned priority;
 };
 
+/* An entry for one ALSA mixer */
+struct pa_alsa_mixer {
+    snd_mixer_t *mixer_handle;
+    pa_alsa_fdlist *fdl;
+    bool used_for_probe_only:1;
+};
+
 /* ALSA mixer element identifier */
 struct pa_alsa_mixer_id {
     char *name;
@@ -165,6 +173,9 @@ struct pa_alsa_jack {
     pa_alsa_path *path;
     PA_LLIST_FIELDS(pa_alsa_jack);
 
+    snd_mixer_t *mixer_handle;
+    char *mixer_device_name;
+
     char *name; /* E g "Headphone" */
     char *alsa_name; /* E g "Headphone Jack" */
     bool has_control; /* is the jack itself present? */
@@ -182,7 +193,7 @@ struct pa_alsa_jack {
     bool append_pcm_to_name;
 };
 
-pa_alsa_jack *pa_alsa_jack_new(pa_alsa_path *path, const char *name);
+pa_alsa_jack *pa_alsa_jack_new(pa_alsa_path *path, const char *mixer_device_name, const char *name);
 void pa_alsa_jack_free(pa_alsa_jack *jack);
 void pa_alsa_jack_set_has_control(pa_alsa_jack *jack, bool has_control);
 void pa_alsa_jack_set_plugged_in(pa_alsa_jack *jack, bool plugged_in);
@@ -201,6 +212,7 @@ struct pa_alsa_path {
     char *description;
     unsigned priority;
     bool autodetect_eld_device;
+    pa_alsa_mixer *eld_mixer_handle;
     int eld_device;
     pa_proplist *proplist;
 
@@ -359,14 +371,11 @@ void pa_alsa_decibel_fix_dump(pa_alsa_decibel_fix *db_fix);
 pa_alsa_mapping *pa_alsa_mapping_get(pa_alsa_profile_set *ps, const char *name);
 
 pa_alsa_profile_set* pa_alsa_profile_set_new(const char *fname, const pa_channel_map *bonus);
-void pa_alsa_profile_set_probe(pa_alsa_profile_set *ps, const char *dev_id, const pa_sample_spec *ss, unsigned default_n_fragments, unsigned default_fragment_size_msec);
+void pa_alsa_profile_set_probe(pa_alsa_profile_set *ps, pa_hashmap *mixers, const char *dev_id, const pa_sample_spec *ss, unsigned default_n_fragments, unsigned default_fragment_size_msec);
 void pa_alsa_profile_set_free(pa_alsa_profile_set *s);
 void pa_alsa_profile_set_dump(pa_alsa_profile_set *s);
 void pa_alsa_profile_set_drop_unsupported(pa_alsa_profile_set *s);
 
-snd_mixer_t *pa_alsa_open_mixer_by_name(const char *dev);
-snd_mixer_t *pa_alsa_open_mixer_for_pcm(snd_pcm_t *pcm, char **ctl_device);
-
 pa_alsa_fdlist *pa_alsa_fdlist_new(void);
 void pa_alsa_fdlist_free(pa_alsa_fdlist *fdl);
 int pa_alsa_fdlist_set_handle(pa_alsa_fdlist *fdl, snd_mixer_t *mixer_handle, snd_hctl_t *hctl_handle, pa_mainloop_api* m);
diff --git a/src/modules/alsa/alsa-sink.c b/src/modules/alsa/alsa-sink.c
index 5ea4b2597449..363b4be2fa25 100644
--- a/src/modules/alsa/alsa-sink.c
+++ b/src/modules/alsa/alsa-sink.c
@@ -105,6 +105,7 @@ struct userdata {
     char *paths_dir;
     pa_alsa_fdlist *mixer_fdl;
     pa_alsa_mixer_pdata *mixer_pd;
+    pa_hashmap *mixers;
     snd_mixer_t *mixer_handle;
     pa_alsa_path_set *mixer_path_set;
     pa_alsa_path *mixer_path;
@@ -2088,13 +2089,16 @@ static void find_mixer(struct userdata *u, pa_alsa_mapping *mapping, const char
     if (!mapping && !element)
         return;
 
+    u->mixers = pa_hashmap_new_full(pa_idxset_string_hash_func, pa_idxset_string_compare_func,
+                                    NULL, (pa_free_cb_t) pa_alsa_mixer_free);
+
     mdev = pa_proplist_gets(mapping->proplist, "alsa.mixer_device");
     if (mdev) {
-        u->mixer_handle = pa_alsa_open_mixer_by_name(mdev);
+        u->mixer_handle = pa_alsa_open_mixer_by_name(u->mixers, mdev, true);
     } else {
-        u->mixer_handle = pa_alsa_open_mixer_for_pcm(u->pcm_handle, &u->control_device);
+        u->mixer_handle = pa_alsa_open_mixer_for_pcm(u->mixers, u->pcm_handle, true);
     }
-    if (!mdev) {
+    if (!u->mixer_handle) {
         pa_log_info("Failed to find a working mixer device.");
         return;
     }
@@ -2121,10 +2125,9 @@ fail:
         u->mixer_path = NULL;
     }
 
-    if (u->mixer_handle) {
-        snd_mixer_close(u->mixer_handle);
-        u->mixer_handle = NULL;
-    }
+    u->mixer_handle = NULL;
+    pa_hashmap_free(u->mixers);
+    u->mixers = NULL;
 }
 
 static int setup_mixer(struct userdata *u, bool ignore_dB) {
@@ -2759,8 +2762,8 @@ static void userdata_free(struct userdata *u) {
     if (u->mixer_path && !u->mixer_path_set && !u->ucm_context)
         pa_alsa_path_free(u->mixer_path);
 
-    if (u->mixer_handle)
-        snd_mixer_close(u->mixer_handle);
+    if (u->mixers)
+        pa_hashmap_free(u->mixers);
 
     if (u->smoother)
         pa_smoother_free(u->smoother);
diff --git a/src/modules/alsa/alsa-source.c b/src/modules/alsa/alsa-source.c
index bd78d45e2a5b..b46e845cc5a7 100644
--- a/src/modules/alsa/alsa-source.c
+++ b/src/modules/alsa/alsa-source.c
@@ -93,6 +93,7 @@ struct userdata {
     char *paths_dir;
     pa_alsa_fdlist *mixer_fdl;
     pa_alsa_mixer_pdata *mixer_pd;
+    pa_hashmap *mixers;
     snd_mixer_t *mixer_handle;
     pa_alsa_path_set *mixer_path_set;
     pa_alsa_path *mixer_path;
@@ -1794,13 +1795,16 @@ static void find_mixer(struct userdata *u, pa_alsa_mapping *mapping, const char
     if (!mapping && !element)
         return;
 
+    u->mixers = pa_hashmap_new_full(pa_idxset_string_hash_func, pa_idxset_string_compare_func,
+                                    NULL, (pa_free_cb_t) pa_alsa_mixer_free);
+
     mdev = pa_proplist_gets(mapping->proplist, "alsa.mixer_device");
     if (mdev) {
-        u->mixer_handle = pa_alsa_open_mixer_by_name(mdev);
+        u->mixer_handle = pa_alsa_open_mixer_by_name(u->mixers, mdev, false);
     } else {
-        u->mixer_handle = pa_alsa_open_mixer_for_pcm(u->pcm_handle, &u->control_device);
+        u->mixer_handle = pa_alsa_open_mixer_for_pcm(u->mixers, u->pcm_handle, false);
     }
-    if (!mdev) {
+    if (!u->mixer_handle) {
         pa_log_info("Failed to find a working mixer device.");
         return;
     }
@@ -1827,10 +1831,9 @@ fail:
         u->mixer_path = NULL;
     }
 
-    if (u->mixer_handle) {
-        snd_mixer_close(u->mixer_handle);
-        u->mixer_handle = NULL;
-    }
+    u->mixer_handle = NULL;
+    pa_hashmap_free(u->mixers);
+    u->mixers = NULL;
 }
 
 static int setup_mixer(struct userdata *u, bool ignore_dB) {
@@ -2403,8 +2406,8 @@ static void userdata_free(struct userdata *u) {
     if (u->mixer_path && !u->mixer_path_set && !u->ucm_context)
         pa_alsa_path_free(u->mixer_path);
 
-    if (u->mixer_handle)
-        snd_mixer_close(u->mixer_handle);
+    if (u->mixers)
+        pa_hashmap_free(u->mixers);
 
     if (u->smoother)
         pa_smoother_free(u->smoother);
diff --git a/src/modules/alsa/alsa-ucm.c b/src/modules/alsa/alsa-ucm.c
index a64505a0c781..b9a4b8c4b436 100644
--- a/src/modules/alsa/alsa-ucm.c
+++ b/src/modules/alsa/alsa-ucm.c
@@ -820,13 +820,13 @@ static int pa_alsa_ucm_device_cmp(const void *a, const void *b) {
     return strcmp(pa_proplist_gets(d1->proplist, PA_ALSA_PROP_UCM_NAME), pa_proplist_gets(d2->proplist, PA_ALSA_PROP_UCM_NAME));
 }
 
-static void probe_volumes(pa_hashmap *hash, bool is_sink, snd_pcm_t *pcm_handle, bool ignore_dB) {
+static void probe_volumes(pa_hashmap *hash, bool is_sink, snd_pcm_t *pcm_handle, pa_hashmap *mixers, bool ignore_dB) {
     pa_device_port *port;
     pa_alsa_path *path;
     pa_alsa_ucm_port_data *data;
     pa_alsa_ucm_device *dev;
-    snd_mixer_t *mixer_handle = NULL;
-    const char *profile, *mdev_opened = NULL, *mdev, *mdev2;
+    snd_mixer_t *mixer_handle;
+    const char *profile, *mdev, *mdev2;
     void *state, *state2;
     int idx;
 
@@ -843,16 +843,9 @@ static void probe_volumes(pa_hashmap *hash, bool is_sink, snd_pcm_t *pcm_handle,
             mdev = mdev2;
         }
 
-        if (!mdev_opened || !pa_streq(mdev_opened, mdev)) {
-            if (mixer_handle) {
-                snd_mixer_close(mixer_handle);
-                mdev_opened = NULL;
-            }
-            if (!(mixer_handle = pa_alsa_open_mixer_by_name(mdev))) {
-                pa_log_error("Failed to find a working mixer device (%s).", mdev);
-                goto fail;
-            }
-            mdev_opened = mdev;
+        if (!(mixer_handle = pa_alsa_open_mixer_by_name(mixers, mdev, true))) {
+            pa_log_error("Failed to find a working mixer device (%s).", mdev);
+            goto fail;
         }
 
         PA_HASHMAP_FOREACH_KV(profile, path, data->paths, state2) {
@@ -867,9 +860,6 @@ static void probe_volumes(pa_hashmap *hash, bool is_sink, snd_pcm_t *pcm_handle,
         }
     }
 
-    if (mixer_handle)
-        snd_mixer_close(mixer_handle);
-
     return;
 
 fail:
@@ -1194,7 +1184,7 @@ void pa_alsa_ucm_add_ports(
     pa_alsa_ucm_add_ports_combination(*p, context, is_sink, card->ports, NULL, card->core);
 
     /* now set up volume paths if any */
-    probe_volumes(*p, is_sink, pcm_handle, ignore_dB);
+    probe_volumes(*p, is_sink, pcm_handle, context->ucm->mixers, ignore_dB);
 
     /* then set property PA_PROP_DEVICE_INTENDED_ROLES */
     merged_roles = pa_xstrdup(pa_proplist_gets(proplist, PA_PROP_DEVICE_INTENDED_ROLES));
@@ -1543,6 +1533,7 @@ static pa_alsa_jack* ucm_get_jack(pa_alsa_ucm_config *ucm, pa_alsa_ucm_device *d
     pa_alsa_jack *j;
     const char *device_name;
     const char *jack_control;
+    const char *mixer_device_name;
     char *name;
 
     pa_assert(ucm);
@@ -1585,7 +1576,14 @@ static pa_alsa_jack* ucm_get_jack(pa_alsa_ucm_config *ucm, pa_alsa_ucm_device *d
         if (pa_streq(j->name, name))
             goto finish;
 
-    j = pa_alsa_jack_new(NULL, name);
+    mixer_device_name = get_jack_mixer_device(device, true);
+    if (!mixer_device_name)
+        mixer_device_name = get_jack_mixer_device(device, false);
+    if (!mixer_device_name) {
+        pa_log("[%s] No mixer device name for JackControl \"%s\"", device_name, jack_control);
+        return NULL;
+    }
+    j = pa_alsa_jack_new(NULL, mixer_device_name, name);
     PA_LLIST_PREPEND(pa_alsa_jack, ucm->jacks, j);
 
 finish:
@@ -1765,44 +1763,28 @@ static void profile_finalize_probing(pa_alsa_profile *p) {
     }
 }
 
-static void ucm_mapping_jack_probe(pa_alsa_mapping *m) {
-    snd_mixer_t *mixer_handle = NULL;
+static void ucm_mapping_jack_probe(pa_alsa_mapping *m, pa_hashmap *mixers) {
+    snd_mixer_t *mixer_handle;
     pa_alsa_ucm_mapping_context *context = &m->ucm_context;
     pa_alsa_ucm_device *dev;
-    bool is_sink = m->direction == PA_ALSA_DIRECTION_OUTPUT;
-    const char *mdev_opened = NULL, *mdev;
     uint32_t idx;
 
     PA_IDXSET_FOREACH(dev, context->ucm_devices, idx) {
         bool has_control;
 
-        if (!dev->jack)
+        if (!dev->jack || !dev->jack->mixer_device_name)
             continue;
 
-        mdev = get_jack_mixer_device(dev, is_sink);
-        if (mdev == NULL) {
-            pa_log_error("Unable to determine mixer device for jack %s", dev->jack->name);
+        mixer_handle = pa_alsa_open_mixer_by_name(mixers, dev->jack->mixer_device_name, true);
+        if (!mixer_handle) {
+            pa_log_error("Unable to determine open mixer device '%s' for jack %s", dev->jack->mixer_device_name, dev->jack->name);
             continue;
         }
 
-        if (!mdev_opened || !pa_streq(mdev_opened, mdev)) {
-            if (mixer_handle) {
-                snd_mixer_close(mixer_handle);
-                mdev_opened = NULL;
-            }
-            mixer_handle = pa_alsa_open_mixer_by_name(mdev);
-            if (!mixer_handle)
-                continue;
-            mdev_opened = mdev;
-        }
-
         has_control = pa_alsa_mixer_find_card(mixer_handle, dev->jack->alsa_name, 0) != NULL;
         pa_alsa_jack_set_has_control(dev->jack, has_control);
         pa_log_info("UCM jack %s has_control=%d", dev->jack->name, dev->jack->has_control);
     }
-
-    if (mixer_handle)
-        snd_mixer_close(mixer_handle);
 }
 
 static void ucm_probe_profile_set(pa_alsa_ucm_config *ucm, pa_alsa_profile_set *ps) {
@@ -1860,11 +1842,11 @@ static void ucm_probe_profile_set(pa_alsa_ucm_config *ucm, pa_alsa_profile_set *
 
         PA_IDXSET_FOREACH(m, p->output_mappings, idx)
             if (!PA_UCM_IS_MODIFIER_MAPPING(m))
-                ucm_mapping_jack_probe(m);
+                ucm_mapping_jack_probe(m, ucm->mixers);
 
         PA_IDXSET_FOREACH(m, p->input_mappings, idx)
             if (!PA_UCM_IS_MODIFIER_MAPPING(m))
-                ucm_mapping_jack_probe(m);
+                ucm_mapping_jack_probe(m, ucm->mixers);
 
         profile_finalize_probing(p);
     }
diff --git a/src/modules/alsa/alsa-ucm.h b/src/modules/alsa/alsa-ucm.h
index 014bc334ad67..49362992865b 100644
--- a/src/modules/alsa/alsa-ucm.h
+++ b/src/modules/alsa/alsa-ucm.h
@@ -248,6 +248,7 @@ struct pa_alsa_ucm_config {
     snd_use_case_mgr_t *ucm_mgr;
     pa_alsa_ucm_verb *active_verb;
 
+    pa_hashmap *mixers;
     PA_LLIST_HEAD(pa_alsa_ucm_verb, verbs);
     PA_LLIST_HEAD(pa_alsa_jack, jacks);
 };
diff --git a/src/modules/alsa/alsa-util.c b/src/modules/alsa/alsa-util.c
index 08a144782394..34930c9fa155 100644
--- a/src/modules/alsa/alsa-util.c
+++ b/src/modules/alsa/alsa-util.c
@@ -1726,83 +1726,86 @@ static int prepare_mixer(snd_mixer_t *mixer, const char *dev) {
     return 0;
 }
 
-snd_mixer_t *pa_alsa_open_mixer(int alsa_card_index, char **ctl_device) {
-    int err;
-    snd_mixer_t *m;
-    char *md;
-    snd_pcm_info_t* info;
-    snd_pcm_info_alloca(&info);
-
-    if ((err = snd_mixer_open(&m, 0)) < 0) {
-        pa_log("Error opening mixer: %s", pa_alsa_strerror(err));
-        return NULL;
-    }
-
-    /* Then, try by card index */
-    md = pa_sprintf_malloc("hw:%i", alsa_card_index);
-    if (prepare_mixer(m, md) >= 0) {
-
-        if (ctl_device)
-            *ctl_device = md;
-        else
-            pa_xfree(md);
-
-        return m;
-    }
-
+snd_mixer_t *pa_alsa_open_mixer(pa_hashmap *mixers, int alsa_card_index, bool probe) {
+    char *md = pa_sprintf_malloc("hw:%i", alsa_card_index);
+    snd_mixer_t *m = pa_alsa_open_mixer_by_name(mixers, md, probe);
     pa_xfree(md);
-
-    snd_mixer_close(m);
-    return NULL;
+    return m;
 }
 
-snd_mixer_t *pa_alsa_open_mixer_by_name(const char *dev) {
+snd_mixer_t *pa_alsa_open_mixer_by_name(pa_hashmap *mixers, const char *dev, bool probe) {
     int err;
     snd_mixer_t *m;
+    pa_alsa_mixer *pm;
 
+    pa_assert(mixers);
     pa_assert(dev);
 
+    pm = pa_hashmap_get(mixers, dev);
+    if (pm) {
+        if (!probe)
+            pm->used_for_probe_only = false;
+        return pm->mixer_handle;
+    }
+
     if ((err = snd_mixer_open(&m, 0)) < 0) {
         pa_log("Error opening mixer: %s", pa_alsa_strerror(err));
         return NULL;
     }
 
-    if (prepare_mixer(m, dev) >= 0)
-        return m;
+    if (prepare_mixer(m, dev) >= 0) {
+        pm = pa_xnew0(pa_alsa_mixer, 1);
+        if (pm) {
+            pm->used_for_probe_only = probe;
+            pm->mixer_handle = m;
+            pa_hashmap_put(mixers, pa_xstrdup(dev), pm);
+            return m;
+        }
+    }
 
     snd_mixer_close(m);
     return NULL;
 }
 
-snd_mixer_t *pa_alsa_open_mixer_for_pcm(snd_pcm_t *pcm, char **ctl_device) {
-    snd_mixer_t *m;
+snd_mixer_t *pa_alsa_open_mixer_for_pcm(pa_hashmap *mixers, snd_pcm_t *pcm, bool probe) {
     snd_pcm_info_t* info;
     snd_pcm_info_alloca(&info);
 
     pa_assert(pcm);
 
     if (snd_pcm_info(pcm, info) >= 0) {
-        char *md;
         int card_idx;
 
-        if ((card_idx = snd_pcm_info_get_card(info)) >= 0) {
+        if ((card_idx = snd_pcm_info_get_card(info)) >= 0)
+            return pa_alsa_open_mixer(mixers, card_idx, probe);
+    }
 
-            md = pa_sprintf_malloc("hw:%i", card_idx);
-            m = pa_alsa_open_mixer_by_name(md);
-            if (m) {
-                if (ctl_device)
-                    *ctl_device = md;
-                else
-                    pa_xfree(md);
+    return NULL;
+}
 
-                return m;
-            }
+void pa_alsa_mixer_set_fdlist(pa_hashmap *mixers, snd_mixer_t *mixer_handle, pa_mainloop_api *ml)
+{
+    pa_alsa_mixer *pm;
+    void *state;
 
-            pa_xfree(md);
+    PA_HASHMAP_FOREACH(pm, mixers, state)
+        if (pm->mixer_handle == mixer_handle) {
+            pm->used_for_probe_only = false;
+            if (!pm->fdl) {
+                pm->fdl = pa_alsa_fdlist_new();
+                if (pm->fdl)
+                    pa_alsa_fdlist_set_handle(pm->fdl, pm->mixer_handle, NULL, ml);
+            }
         }
-    }
+}
 
-    return NULL;
+void pa_alsa_mixer_free(pa_alsa_mixer *mixer)
+{
+    if (mixer->fdl)
+        pa_alsa_fdlist_free(mixer->fdl);
+    if (mixer->mixer_handle)
+        snd_mixer_close(mixer->mixer_handle);
+    pa_xfree(mixer);
 }
 
 int pa_alsa_get_hdmi_eld(snd_hctl_elem_t *elem, pa_hdmi_eld *eld) {
diff --git a/src/modules/alsa/alsa-util.h b/src/modules/alsa/alsa-util.h
index ceca48809400..0d3d5af13370 100644
--- a/src/modules/alsa/alsa-util.h
+++ b/src/modules/alsa/alsa-util.h
@@ -144,7 +144,11 @@ bool pa_alsa_may_tsched(bool want);
 snd_mixer_elem_t *pa_alsa_mixer_find_card(snd_mixer_t *mixer, const char *name, unsigned int device);
 snd_mixer_elem_t *pa_alsa_mixer_find_pcm(snd_mixer_t *mixer, const char *name, unsigned int device);
 
-snd_mixer_t *pa_alsa_open_mixer(int alsa_card_index, char **ctl_device);
+snd_mixer_t *pa_alsa_open_mixer(pa_hashmap *mixers, int alsa_card_index, bool probe);
+snd_mixer_t *pa_alsa_open_mixer_by_name(pa_hashmap *mixers, const char *dev, bool probe);
+snd_mixer_t *pa_alsa_open_mixer_for_pcm(pa_hashmap *mixers, snd_pcm_t *pcm, bool probe);
+void pa_alsa_mixer_set_fdlist(pa_hashmap *mixers, snd_mixer_t *mixer, pa_mainloop_api *ml);
+void pa_alsa_mixer_free(pa_alsa_mixer *mixer);
 
 typedef struct pa_hdmi_eld pa_hdmi_eld;
 struct pa_hdmi_eld {
diff --git a/src/modules/alsa/module-alsa-card.c b/src/modules/alsa/module-alsa-card.c
index ba7a19a38983..3b2f99fc4e54 100644
--- a/src/modules/alsa/module-alsa-card.c
+++ b/src/modules/alsa/module-alsa-card.c
@@ -111,9 +111,8 @@ struct userdata {
     char *device_id;
     int alsa_card_index;
 
-    snd_mixer_t *mixer_handle;
+    pa_hashmap *mixers;
     pa_hashmap *jacks;
-    pa_alsa_fdlist *mixer_fdl;
 
     pa_card *card;
 
@@ -569,9 +568,6 @@ static void init_eld_ctls(struct userdata *u) {
     void *state;
     pa_device_port *port;
 
-    if (!u->mixer_handle)
-        return;
-
     /* The code in this function expects ports to have a pa_alsa_port_data
      * struct as their data, but in UCM mode ports don't have any data. Hence,
      * the ELD controls can't currently be used in UCM mode. */
@@ -580,6 +576,7 @@ static void init_eld_ctls(struct userdata *u) {
 
     PA_HASHMAP_FOREACH(port, u->card->ports, state) {
         pa_alsa_port_data *data = PA_DEVICE_PORT_DATA(port);
+        snd_mixer_t *mixer_handle;
         snd_mixer_elem_t* melem;
         int device;
 
@@ -588,8 +585,13 @@ static void init_eld_ctls(struct userdata *u) {
         if (device < 0)
             continue;
 
-        melem = pa_alsa_mixer_find_pcm(u->mixer_handle, "ELD", device);
+        mixer_handle = pa_alsa_open_mixer(u->mixers, u->alsa_card_index, true);
+        if (!mixer_handle)
+            continue;
+
+        melem = pa_alsa_mixer_find_pcm(mixer_handle, "ELD", device);
         if (melem) {
+            pa_alsa_mixer_set_fdlist(u->mixers, mixer_handle, u->core->mainloop);
             snd_mixer_elem_set_callback(melem, hdmi_eld_changed);
             snd_mixer_elem_set_callback_private(melem, u);
             hdmi_eld_changed(melem, 0);
@@ -630,25 +632,31 @@ static void init_jacks(struct userdata *u) {
     if (pa_hashmap_size(u->jacks) == 0)
         return;
 
-    u->mixer_fdl = pa_alsa_fdlist_new();
-
-    u->mixer_handle = pa_alsa_open_mixer(u->alsa_card_index, NULL);
-    if (u->mixer_handle && pa_alsa_fdlist_set_handle(u->mixer_fdl, u->mixer_handle, NULL, u->core->mainloop) >= 0) {
-        PA_HASHMAP_FOREACH(jack, u->jacks, state) {
-            jack->melem = pa_alsa_mixer_find_card(u->mixer_handle, jack->alsa_name, 0);
-            if (!jack->melem) {
-                pa_log_warn("Jack '%s' seems to have disappeared.", jack->alsa_name);
-                pa_alsa_jack_set_has_control(jack, false);
-                continue;
+    PA_HASHMAP_FOREACH(jack, u->jacks, state) {
+        if (!jack->mixer_device_name) {
+            jack->mixer_handle = pa_alsa_open_mixer(u->mixers, u->alsa_card_index, false);
+            if (!jack->mixer_handle) {
+               pa_log("Failed to open mixer for card %d for jack detection", u->alsa_card_index);
+               continue;
+            }
+        } else {
+            jack->mixer_handle = pa_alsa_open_mixer_by_name(u->mixers, jack->mixer_device_name, false);
+            if (!jack->mixer_handle) {
+               pa_log("Failed to open mixer '%s' for jack detection", jack->mixer_device_name);
+              continue;
             }
-            snd_mixer_elem_set_callback(jack->melem, report_jack_state);
-            snd_mixer_elem_set_callback_private(jack->melem, u);
-            report_jack_state(jack->melem, 0);
         }
-
-    } else
-        pa_log("Failed to open mixer for jack detection");
-
+        pa_alsa_mixer_set_fdlist(u->mixers, jack->mixer_handle, u->core->mainloop);
+        jack->melem = pa_alsa_mixer_find_card(jack->mixer_handle, jack->alsa_name, 0);
+        if (!jack->melem) {
+            pa_log_warn("Jack '%s' seems to have disappeared.", jack->alsa_name);
+            pa_alsa_jack_set_has_control(jack, false);
+            continue;
+        }
+        snd_mixer_elem_set_callback(jack->melem, report_jack_state);
+        snd_mixer_elem_set_callback_private(jack->melem, u);
+        report_jack_state(jack->melem, 0);
+    }
 }
 
 static void set_card_name(pa_card_new_data *data, pa_modargs *ma, const char *device_id) {
@@ -772,6 +780,10 @@ int pa__init(pa_module *m) {
     u->use_ucm = true;
     u->ucm.core = m->core;
 
+    u->mixers = pa_hashmap_new_full(pa_idxset_string_hash_func, pa_idxset_string_compare_func,
+                                    pa_xfree, (pa_free_cb_t) pa_alsa_mixer_free);
+    u->ucm.mixers = u->mixers; /* alias */
+
     if (!(u->modargs = pa_modargs_new(m->argument, valid_modargs))) {
         pa_log("Failed to parse module arguments.");
         goto fail;
@@ -852,7 +864,7 @@ int pa__init(pa_module *m) {
 
     u->profile_set->ignore_dB = ignore_dB;
 
-    pa_alsa_profile_set_probe(u->profile_set, u->device_id, &m->core->default_sample_spec, m->core->default_n_fragments, m->core->default_fragment_size_msec);
+    pa_alsa_profile_set_probe(u->profile_set, u->mixers, u->device_id, &m->core->default_sample_spec, m->core->default_n_fragments, m->core->default_fragment_size_msec);
     pa_alsa_profile_set_dump(u->profile_set);
 
     pa_card_new_data_init(&data);
@@ -952,6 +964,16 @@ int pa__init(pa_module *m) {
     init_profile(u);
     init_eld_ctls(u);
 
+    /* Remove all probe only mixers */
+    if (u->mixers) {
+       const char *devname;
+       pa_alsa_mixer *pm;
+       void *state;
+       PA_HASHMAP_FOREACH_KV(devname, pm, u->mixers, state)
+           if (pm->used_for_probe_only)
+               pa_hashmap_remove_and_free(u->mixers, devname);
+    }
+
     if (reserve)
         pa_reserve_wrapper_unref(reserve);
 
@@ -1002,10 +1024,8 @@ void pa__done(pa_module*m) {
     if (!(u = m->userdata))
         goto finish;
 
-    if (u->mixer_fdl)
-        pa_alsa_fdlist_free(u->mixer_fdl);
-    if (u->mixer_handle)
-        snd_mixer_close(u->mixer_handle);
+    if (u->mixers)
+        pa_hashmap_free(u->mixers);
     if (u->jacks)
         pa_hashmap_free(u->jacks);
 
-- 
2.16.4