card: handle sticky profile flag

New card database entry version 5 for card profile is sticky flag.
New messaging API handlers set-profile-sticky and get-profile-sticky.

When card profile is sticky, always restore it even if it is unavailable,
and prevent switching from it when ports become unavailable.

Part-of: <https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/568>

src/modules/module-card-restore.c

@@ -67,7 +67,7 @@ struct userdata {
     bool restore_bluetooth_profile;
 };
 
-#define ENTRY_VERSION 4
+#define ENTRY_VERSION 5
 
 struct port_info {
     char *name;
@@ -80,6 +80,7 @@ struct entry {
     pa_hashmap *ports; /* Port name -> struct port_info */
     char *preferred_input_port;
     char *preferred_output_port;
+    bool profile_is_sticky; /* since version 5; must be restored together with profile name */
 };
 
 static void save_time_callback(pa_mainloop_api*a, pa_time_event* e, const struct timeval *t, void *userdata) {
@@ -153,7 +154,8 @@ static struct entry *entry_from_card(pa_card *card) {
     pa_assert(card);
 
     entry = entry_new();
-    if (card->save_profile)
+    entry->profile_is_sticky = card->profile_is_sticky;
+    if (card->save_profile || entry->profile_is_sticky)
         entry->profile = pa_xstrdup(card->active_profile->name);
 
     PA_HASHMAP_FOREACH(port, card->ports, state) {
@@ -189,6 +191,9 @@ static bool entrys_equal(struct entry *a, struct entry *b) {
     if (!pa_safe_streq(a->preferred_output_port, b->preferred_output_port))
         return false;
 
+    if (a->profile_is_sticky != b->profile_is_sticky)
+        return false;
+
     return true;
 }
 
@@ -217,6 +222,8 @@ static bool entry_write(struct userdata *u, const char *name, const struct entry
     pa_tagstruct_puts(t, e->preferred_input_port);
     pa_tagstruct_puts(t, e->preferred_output_port);
 
+    pa_tagstruct_put_boolean(t, e->profile_is_sticky);
+
     key.data = (char *) name;
     key.size = strlen(name);
 
@@ -342,6 +349,14 @@ static struct entry* entry_read(struct userdata *u, const char *name) {
         e->preferred_output_port = pa_xstrdup(preferred_output_port);
     }
 
+    if (version >= 5) {
+        bool profile_is_sticky;
+        if (pa_tagstruct_get_boolean(t, &profile_is_sticky) < 0)
+            goto fail;
+
+        e->profile_is_sticky = profile_is_sticky;
+    }
+
     if (!pa_tagstruct_eof(t))
         goto fail;
 
@@ -437,11 +452,12 @@ static pa_hook_result_t card_profile_changed_callback(pa_core *c, pa_card *card,
 
     pa_assert(card);
 
-    if (!card->save_profile)
+    if (!card->save_profile && !card->profile_is_sticky)
         return PA_HOOK_OK;
 
     if ((entry = entry_read(u, card->name))) {
         pa_xfree(entry->profile);
+        entry->profile_is_sticky = card->profile_is_sticky;
         entry->profile = pa_xstrdup(card->active_profile->name);
         pa_log_info("Storing card profile for card %s.", card->name);
     } else {
@@ -565,12 +581,18 @@ static pa_hook_result_t card_choose_initial_profile_callback(pa_core *core, pa_c
             goto finish;
     }
 
+    card->profile_is_sticky = e->profile_is_sticky;
+    pa_log_info("Profile '%s' was previously %s for card %s.",
+            e->profile,
+            card->profile_is_sticky ? "sticky" : "automatically selected",
+            card->name);
+
     if (e->profile[0]) {
         pa_card_profile *profile;
 
         profile = pa_hashmap_get(card->profiles, e->profile);
         if (profile) {
-            if (profile->available != PA_AVAILABLE_NO) {
+            if (profile->available != PA_AVAILABLE_NO || card->profile_is_sticky) {
                 pa_log_info("Restoring profile '%s' for card %s.", profile->name, card->name);
                 pa_card_set_profile(card, profile, true);
             } else

src/modules/module-switch-on-port-available.c

@@ -137,6 +137,11 @@ static int try_to_switch_profile(pa_device_port *port) {
     void *state;
     unsigned best_prio = 0;
 
+    if (port->card->profile_is_sticky) {
+        pa_log_info("Keeping sticky card profile '%s'", port->card->active_profile->name);
+        return -1;
+    }
+
     pa_log_debug("Finding best profile for port %s, preferred = %s",
                  port->name, pa_strnull(port->preferred_profile));
 
@@ -391,6 +396,11 @@ static pa_hook_result_t card_profile_available_hook_callback(pa_core *c, pa_card
     if (!pa_streq(profile->name, card->active_profile->name))
         return PA_HOOK_OK;
 
+    if (card->profile_is_sticky) {
+        pa_log_info("Keeping sticky card profile '%s'", profile->name);
+        return PA_HOOK_OK;
+    }
+
     pa_log_debug("Active profile %s on card %s became unavailable, switching to another profile", profile->name, card->name);
     pa_card_set_profile(card, find_best_profile(card), false);