X-Git-Url: https://code.delx.au/pulseaudio/blobdiff_plain/983aa5d44bb98f89d5f22ff03dcfc60e62c9f638..bee86af3ccc247834bf38a57296958f9cd35ffc4:/src/modules/module-udev-detect.c

diff --git a/src/modules/module-udev-detect.c b/src/modules/module-udev-detect.c
index 1ad6fa2d..c28c8676 100644
--- a/src/modules/module-udev-detect.c
+++ b/src/modules/module-udev-detect.c
@@ -25,32 +25,54 @@
 
 #include <errno.h>
 #include <limits.h>
+#include <dirent.h>
 #include <sys/inotify.h>
 #include <libudev.h>
 
+#include <pulse/timeval.h>
+
 #include <pulsecore/modargs.h>
 #include <pulsecore/core-error.h>
 #include <pulsecore/core-util.h>
 #include <pulsecore/namereg.h>
+#include <pulsecore/ratelimit.h>
+#include <pulsecore/strbuf.h>
 
 #include "module-udev-detect-symdef.h"
 
 PA_MODULE_AUTHOR("Lennart Poettering");
 PA_MODULE_DESCRIPTION("Detect available audio hardware and load matching drivers");
 PA_MODULE_VERSION(PACKAGE_VERSION);
-PA_MODULE_LOAD_ONCE(TRUE);
+PA_MODULE_LOAD_ONCE(true);
+PA_MODULE_USAGE(
+        "tsched=<enable system timer based scheduling mode?> "
+        "tsched_buffer_size=<buffer size when using timer based scheduling> "
+        "fixed_latency_range=<disable latency range changes on underrun?> "
+        "ignore_dB=<ignore dB information from the device?> "
+        "deferred_volume=<syncronize sw and hw volume changes in IO-thread?> "
+        "use_ucm=<use ALSA UCM for card configuration?>");
 
 struct device {
     char *path;
-    pa_bool_t accessible;
+    bool need_verify;
     char *card_name;
+    char *args;
     uint32_t module;
+    pa_ratelimit ratelimit;
 };
 
 struct userdata {
     pa_core *core;
     pa_hashmap *devices;
-    pa_bool_t use_tsched;
+
+    bool use_tsched:1;
+    bool tsched_buffer_size_valid:1;
+    bool fixed_latency_range:1;
+    bool ignore_dB:1;
+    bool deferred_volume:1;
+    bool use_ucm:1;
+
+    uint32_t tsched_buffer_size;
 
     struct udev* udev;
     struct udev_monitor *monitor;
@@ -62,14 +84,22 @@ struct userdata {
 
 static const char* const valid_modargs[] = {
     "tsched",
+    "tsched_buffer_size",
+    "fixed_latency_range",
+    "ignore_dB",
+    "deferred_volume",
+    "use_ucm",
     NULL
 };
 
+static int setup_inotify(struct userdata *u);
+
 static void device_free(struct device *d) {
     pa_assert(d);
 
     pa_xfree(d->path);
     pa_xfree(d->card_name);
+    pa_xfree(d->args);
     pa_xfree(d);
 }
 
@@ -88,35 +118,267 @@ static const char *path_get_card_id(const char *path) {
     return e + 5;
 }
 
+static char *card_get_sysattr(const char *card_idx, const char *name) {
+    struct udev *udev;
+    struct udev_device *card = NULL;
+    char *t, *r = NULL;
+    const char *v;
+
+    pa_assert(card_idx);
+    pa_assert(name);
+
+    if (!(udev = udev_new())) {
+        pa_log_error("Failed to allocate udev context.");
+        goto finish;
+    }
+
+    t = pa_sprintf_malloc("/sys/class/sound/card%s", card_idx);
+    card = udev_device_new_from_syspath(udev, t);
+    pa_xfree(t);
+
+    if (!card) {
+        pa_log_error("Failed to get card object.");
+        goto finish;
+    }
+
+    if ((v = udev_device_get_sysattr_value(card, name)) && *v)
+        r = pa_xstrdup(v);
+
+finish:
+
+    if (card)
+        udev_device_unref(card);
+
+    if (udev)
+        udev_unref(udev);
+
+    return r;
+}
+
+static bool pcm_is_modem(const char *card_idx, const char *pcm) {
+    char *sysfs_path, *pcm_class;
+    bool is_modem;
+
+    pa_assert(card_idx);
+    pa_assert(pcm);
+
+    /* Check /sys/class/sound/card.../pcmC...../pcm_class. An HDA
+     * modem can be used simultaneously with generic
+     * playback/record. */
+
+    sysfs_path = pa_sprintf_malloc("pcmC%sD%s/pcm_class", card_idx, pcm);
+    pcm_class = card_get_sysattr(card_idx, sysfs_path);
+    is_modem = pcm_class && pa_streq(pcm_class, "modem");
+    pa_xfree(pcm_class);
+    pa_xfree(sysfs_path);
+
+    return is_modem;
+}
+
+static bool is_card_busy(const char *id) {
+    char *card_path = NULL, *pcm_path = NULL, *sub_status = NULL;
+    DIR *card_dir = NULL, *pcm_dir = NULL;
+    FILE *status_file = NULL;
+    size_t len;
+    struct dirent *space = NULL, *de;
+    bool busy = false;
+    int r;
+
+    pa_assert(id);
+
+    /* This simply uses /proc/asound/card.../pcm.../sub.../status to
+     * check whether there is still a process using this audio device. */
+
+    card_path = pa_sprintf_malloc("/proc/asound/card%s", id);
+
+    if (!(card_dir = opendir(card_path))) {
+        pa_log_warn("Failed to open %s: %s", card_path, pa_cstrerror(errno));
+        goto fail;
+    }
+
+    len = offsetof(struct dirent, d_name) + fpathconf(dirfd(card_dir), _PC_NAME_MAX) + 1;
+    space = pa_xmalloc(len);
+
+    for (;;) {
+        de = NULL;
+
+        if ((r = readdir_r(card_dir, space, &de)) != 0) {
+            pa_log_warn("readdir_r() failed: %s", pa_cstrerror(r));
+            goto fail;
+        }
+
+        if (!de)
+            break;
+
+        if (!pa_startswith(de->d_name, "pcm"))
+            continue;
+
+        if (pcm_is_modem(id, de->d_name + 3))
+            continue;
+
+        pa_xfree(pcm_path);
+        pcm_path = pa_sprintf_malloc("%s/%s", card_path, de->d_name);
+
+        if (pcm_dir)
+            closedir(pcm_dir);
+
+        if (!(pcm_dir = opendir(pcm_path))) {
+            pa_log_warn("Failed to open %s: %s", pcm_path, pa_cstrerror(errno));
+            continue;
+        }
+
+        for (;;) {
+            char line[32];
+
+            if ((r = readdir_r(pcm_dir, space, &de)) != 0) {
+                pa_log_warn("readdir_r() failed: %s", pa_cstrerror(r));
+                goto fail;
+            }
+
+            if (!de)
+                break;
+
+            if (!pa_startswith(de->d_name, "sub"))
+                continue;
+
+            pa_xfree(sub_status);
+            sub_status = pa_sprintf_malloc("%s/%s/status", pcm_path, de->d_name);
+
+            if (status_file)
+                fclose(status_file);
+
+            if (!(status_file = pa_fopen_cloexec(sub_status, "r"))) {
+                pa_log_warn("Failed to open %s: %s", sub_status, pa_cstrerror(errno));
+                continue;
+            }
+
+            if (!(fgets(line, sizeof(line)-1, status_file))) {
+                pa_log_warn("Failed to read from %s: %s", sub_status, pa_cstrerror(errno));
+                continue;
+            }
+
+            if (!pa_streq(line, "closed\n")) {
+                busy = true;
+                break;
+            }
+        }
+    }
+
+fail:
+
+    pa_xfree(card_path);
+    pa_xfree(pcm_path);
+    pa_xfree(sub_status);
+    pa_xfree(space);
+
+    if (card_dir)
+        closedir(card_dir);
+
+    if (pcm_dir)
+        closedir(pcm_dir);
+
+    if (status_file)
+        fclose(status_file);
+
+    return busy;
+}
+
 static void verify_access(struct userdata *u, struct device *d) {
     char *cd;
     pa_card *card;
+    bool accessible;
 
     pa_assert(u);
     pa_assert(d);
 
-    if (!(card = pa_namereg_get(u->core, d->card_name, PA_NAMEREG_CARD)))
-        return;
+    cd = pa_sprintf_malloc("/dev/snd/controlC%s", path_get_card_id(d->path));
+    accessible = access(cd, R_OK|W_OK) >= 0;
+    pa_log_debug("%s is accessible: %s", cd, pa_yes_no(accessible));
 
-    cd = pa_sprintf_malloc("%s/snd/controlC%s", udev_get_dev_path(u->udev), path_get_card_id(d->path));
-    d->accessible = access(cd, W_OK) >= 0;
-    pa_log_info("%s is accessible: %s", cd, pa_yes_no(d->accessible));
     pa_xfree(cd);
 
-    pa_card_suspend(card, !d->accessible, PA_SUSPEND_SESSION);
+    if (d->module == PA_INVALID_INDEX) {
+
+        /* If we are not loaded, try to load */
+
+        if (accessible) {
+            pa_module *m;
+            bool busy;
+
+            /* Check if any of the PCM devices that belong to this
+             * card are currently busy. If they are, don't try to load
+             * right now, to make sure the probing phase can
+             * successfully complete. When the current user of the
+             * device closes it we will get another notification via
+             * inotify and can then recheck. */
+
+            busy = is_card_busy(path_get_card_id(d->path));
+            pa_log_debug("%s is busy: %s", d->path, pa_yes_no(busy));
+
+            if (!busy) {
+
+                /* So, why do we rate limit here? It's certainly ugly,
+                 * but there seems to be no other way. Problem is
+                 * this: if we are unable to configure/probe an audio
+                 * device after opening it we will close it again and
+                 * the module initialization will fail. This will then
+                 * cause an inotify event on the device node which
+                 * will be forwarded to us. We then try to reopen the
+                 * audio device again, practically entering a busy
+                 * loop.
+                 *
+                 * A clean fix would be if we would be able to ignore
+                 * our own inotify close events. However, inotify
+                 * lacks such functionality. Also, during probing of
+                 * the device we cannot really distinguish between
+                 * other processes causing EBUSY or ourselves, which
+                 * means we have no way to figure out if the probing
+                 * during opening was canceled by a "try again"
+                 * failure or a "fatal" failure. */
+
+                if (pa_ratelimit_test(&d->ratelimit, PA_LOG_DEBUG)) {
+                    pa_log_debug("Loading module-alsa-card with arguments '%s'", d->args);
+                    m = pa_module_load(u->core, "module-alsa-card", d->args);
+
+                    if (m) {
+                        d->module = m->index;
+                        pa_log_info("Card %s (%s) module loaded.", d->path, d->card_name);
+                    } else
+                        pa_log_info("Card %s (%s) failed to load module.", d->path, d->card_name);
+                } else
+                    pa_log_warn("Tried to configure %s (%s) more often than %u times in %llus",
+                                d->path,
+                                d->card_name,
+                                d->ratelimit.burst,
+                                (long long unsigned) (d->ratelimit.interval / PA_USEC_PER_SEC));
+            }
+        }
+
+    } else {
+
+        /* If we are already loaded update suspend status with
+         * accessible boolean */
+
+        if ((card = pa_namereg_get(u->core, d->card_name, PA_NAMEREG_CARD))) {
+            pa_log_debug("%s all sinks and sources of card %s.", accessible ? "Resuming" : "Suspending", d->card_name);
+            pa_card_suspend(card, !accessible, PA_SUSPEND_SESSION);
+        }
+    }
 }
 
 static void card_changed(struct userdata *u, struct udev_device *dev) {
     struct device *d;
     const char *path;
     const char *t;
-    char *card_name, *args;
-    pa_module *m;
     char *n;
+    pa_strbuf *args_buf;
 
     pa_assert(u);
     pa_assert(dev);
 
+    /* Maybe /dev/snd is now available? */
+    setup_inotify(u);
+
     path = udev_device_get_devpath(dev);
 
     if ((d = pa_hashmap_get(u->devices, path))) {
@@ -124,42 +386,48 @@ static void card_changed(struct userdata *u, struct udev_device *dev) {
         return;
     }
 
+    d = pa_xnew0(struct device, 1);
+    d->path = pa_xstrdup(path);
+    d->module = PA_INVALID_INDEX;
+    PA_INIT_RATELIMIT(d->ratelimit, 10*PA_USEC_PER_SEC, 5);
+
     if (!(t = udev_device_get_property_value(dev, "PULSE_NAME")))
         if (!(t = udev_device_get_property_value(dev, "ID_ID")))
             if (!(t = udev_device_get_property_value(dev, "ID_PATH")))
                 t = path_get_card_id(path);
 
     n = pa_namereg_make_valid_name(t);
+    d->card_name = pa_sprintf_malloc("alsa_card.%s", n);
+    args_buf = pa_strbuf_new();
+    pa_strbuf_printf(args_buf,
+                     "device_id=\"%s\" "
+                     "name=\"%s\" "
+                     "card_name=\"%s\" "
+                     "namereg_fail=false "
+                     "tsched=%s "
+                     "fixed_latency_range=%s "
+                     "ignore_dB=%s "
+                     "deferred_volume=%s "
+                     "use_ucm=%s "
+                     "card_properties=\"module-udev-detect.discovered=1\"",
+                     path_get_card_id(path),
+                     n,
+                     d->card_name,
+                     pa_yes_no(u->use_tsched),
+                     pa_yes_no(u->fixed_latency_range),
+                     pa_yes_no(u->ignore_dB),
+                     pa_yes_no(u->deferred_volume),
+                     pa_yes_no(u->use_ucm));
+    pa_xfree(n);
 
-    card_name = pa_sprintf_malloc("alsa_card.%s", n);
-    args = pa_sprintf_malloc("device_id=\"%s\" "
-                             "name=\"%s\" "
-                             "card_name=\"%s\" "
-                             "tsched=%i "
-                             "card_properties=\"module-udev-detect.discovered=1\"",
-                             path_get_card_id(path),
-                             n,
-                             card_name,
-                             (int) u->use_tsched);
-
-    pa_log_debug("Loading module-alsa-card with arguments '%s'", args);
-    m = pa_module_load(u->core, "module-alsa-card", args);
-    pa_xfree(args);
-
-    if (m) {
-        pa_log_info("Card %s (%s) added.", path, n);
-
-        d = pa_xnew(struct device, 1);
-        d->path = pa_xstrdup(path);
-        d->card_name = card_name;
-        d->module = m->index;
-        d->accessible = TRUE;
-
-        pa_hashmap_put(u->devices, d->path, d);
-    } else
-        pa_xfree(card_name);
+    if (u->tsched_buffer_size_valid)
+        pa_strbuf_printf(args_buf, " tsched_buffer_size=%" PRIu32, u->tsched_buffer_size);
 
-    pa_xfree(n);
+    d->args = pa_strbuf_tostring_free(args_buf);
+
+    pa_hashmap_put(u->devices, d->path, d);
+
+    verify_access(u, d);
 }
 
 static void remove_card(struct userdata *u, struct udev_device *dev) {
@@ -172,7 +440,10 @@ static void remove_card(struct userdata *u, struct udev_device *dev) {
         return;
 
     pa_log_info("Card %s removed.", d->path);
-    pa_module_unload_request_by_index(u->core, d->module, TRUE);
+
+    if (d->module != PA_INVALID_INDEX)
+        pa_module_unload_request_by_index(u->core, d->module, true);
+
     device_free(d);
 }
 
@@ -187,7 +458,7 @@ static void process_device(struct userdata *u, struct udev_device *dev) {
         return;
     }
 
-    if ((ff = udev_device_get_property_value(dev, "SOUND_FORM_FACTOR")) &&
+    if ((ff = udev_device_get_property_value(dev, "SOUND_CLASS")) &&
         pa_streq(ff, "modem")) {
         pa_log_debug("Ignoring %s, because it is a modem.", udev_device_get_devpath(dev));
         return;
@@ -197,8 +468,7 @@ static void process_device(struct userdata *u, struct udev_device *dev) {
 
     if (action && pa_streq(action, "remove"))
         remove_card(u, dev);
-    else if ((!action || pa_streq(action, "change")) &&
-             udev_device_get_property_value(dev, "SOUND_INITIALIZED"))
+    else if ((!action || pa_streq(action, "change")) && udev_device_get_property_value(dev, "SOUND_INITIALIZED"))
         card_changed(u, dev);
 
     /* For an explanation why we don't look for 'add' events here
@@ -237,8 +507,10 @@ static void monitor_cb(
         goto fail;
     }
 
-    if (!path_get_card_id(udev_device_get_devpath(dev)))
+    if (!path_get_card_id(udev_device_get_devpath(dev))) {
+        udev_device_unref(dev);
         return;
+    }
 
     process_device(u, dev);
     udev_device_unref(dev);
@@ -249,6 +521,34 @@ fail:
     u->udev_io = NULL;
 }
 
+static bool pcm_node_belongs_to_device(
+        struct device *d,
+        const char *node) {
+
+    char *cd;
+    bool b;
+
+    cd = pa_sprintf_malloc("pcmC%sD", path_get_card_id(d->path));
+    b = pa_startswith(node, cd);
+    pa_xfree(cd);
+
+    return b;
+}
+
+static bool control_node_belongs_to_device(
+        struct device *d,
+        const char *node) {
+
+    char *cd;
+    bool b;
+
+    cd = pa_sprintf_malloc("controlC%s", path_get_card_id(d->path));
+    b = pa_streq(node, cd);
+    pa_xfree(cd);
+
+    return b;
+}
+
 static void inotify_cb(
         pa_mainloop_api*a,
         pa_io_event* e,
@@ -262,10 +562,13 @@ static void inotify_cb(
     } buf;
     struct userdata *u = userdata;
     static int type = 0;
-    pa_bool_t verify = FALSE;
+    bool deleted = false;
+    struct device *d;
+    void *state;
 
     for (;;) {
         ssize_t r;
+        struct inotify_event *event;
 
         pa_zero(buf);
         if ((r = pa_read(fd, &buf, sizeof(buf), &type)) <= 0) {
@@ -277,25 +580,60 @@ static void inotify_cb(
             goto fail;
         }
 
-        if ((buf.e.mask & IN_CLOSE_WRITE) && pa_startswith(buf.e.name, "pcmC"))
-            verify = TRUE;
+        event = &buf.e;
+        while (r > 0) {
+            size_t len;
+
+            if ((size_t) r < sizeof(struct inotify_event)) {
+                pa_log("read() too short.");
+                goto fail;
+            }
+
+            len = sizeof(struct inotify_event) + event->len;
+
+            if ((size_t) r < len) {
+                pa_log("Payload missing.");
+                goto fail;
+            }
+
+            /* From udev we get the guarantee that the control
+             * device's ACL is changed last. To avoid races when ACLs
+             * are changed we hence watch only the control device */
+            if (((event->mask & IN_ATTRIB) && pa_startswith(event->name, "controlC")))
+                PA_HASHMAP_FOREACH(d, u->devices, state)
+                    if (control_node_belongs_to_device(d, event->name))
+                        d->need_verify = true;
+
+            /* ALSA doesn't really give us any guarantee on the closing
+             * order, so let's simply hope */
+            if (((event->mask & IN_CLOSE_WRITE) && pa_startswith(event->name, "pcmC")))
+                PA_HASHMAP_FOREACH(d, u->devices, state)
+                    if (pcm_node_belongs_to_device(d, event->name))
+                        d->need_verify = true;
+
+            /* /dev/snd/ might have been removed */
+            if ((event->mask & (IN_DELETE_SELF|IN_MOVE_SELF)))
+                deleted = true;
+
+            event = (struct inotify_event*) ((uint8_t*) event + len);
+            r -= len;
+        }
     }
 
-    if (verify) {
-        struct device *d;
-        void *state;
-
-        pa_log_debug("Verifying access.");
-
-        PA_HASHMAP_FOREACH(d, u->devices, state)
+    PA_HASHMAP_FOREACH(d, u->devices, state)
+        if (d->need_verify) {
+            d->need_verify = false;
             verify_access(u, d);
-    }
+        }
 
-    return;
+    if (!deleted)
+        return;
 
 fail:
-    a->io_free(u->inotify_io);
-    u->inotify_io = NULL;
+    if (u->inotify_io) {
+        a->io_free(u->inotify_io);
+        u->inotify_io = NULL;
+    }
 
     if (u->inotify_fd >= 0) {
         pa_close(u->inotify_fd);
@@ -304,20 +642,38 @@ fail:
 }
 
 static int setup_inotify(struct userdata *u) {
-    char *dev_snd;
     int r;
 
+    if (u->inotify_fd >= 0)
+        return 0;
+
     if ((u->inotify_fd = inotify_init1(IN_CLOEXEC|IN_NONBLOCK)) < 0) {
         pa_log("inotify_init1() failed: %s", pa_cstrerror(errno));
         return -1;
     }
 
-    dev_snd = pa_sprintf_malloc("%s/snd", udev_get_dev_path(u->udev));
-    r = inotify_add_watch(u->inotify_fd, dev_snd, IN_CLOSE_WRITE);
-    pa_xfree(dev_snd);
+    r = inotify_add_watch(u->inotify_fd, "/dev/snd", IN_ATTRIB|IN_CLOSE_WRITE|IN_DELETE_SELF|IN_MOVE_SELF);
 
     if (r < 0) {
-        pa_log("inotify_add_watch() failed: %s", pa_cstrerror(errno));
+        int saved_errno = errno;
+
+        pa_close(u->inotify_fd);
+        u->inotify_fd = -1;
+
+        if (saved_errno == ENOENT) {
+            pa_log_debug("/dev/snd/ is apparently not existing yet, retrying to create inotify watch later.");
+            return 0;
+        }
+
+        if (saved_errno == ENOSPC) {
+            pa_log("You apparently ran out of inotify watches, probably because Tracker/Beagle took them all away. "
+                   "I wished people would do their homework first and fix inotify before using it for watching whole "
+                   "directory trees which is something the current inotify is certainly not useful for. "
+                   "Please make sure to drop the Tracker/Beagle guys a line complaining about their broken use of inotify.");
+            return 0;
+        }
+
+        pa_log("inotify_add_watch() failed: %s", pa_cstrerror(saved_errno));
         return -1;
     }
 
@@ -332,6 +688,8 @@ int pa__init(pa_module *m) {
     struct udev_enumerate *enumerate = NULL;
     struct udev_list_entry *item = NULL, *first = NULL;
     int fd;
+    bool use_tsched = true, fixed_latency_range = false, ignore_dB = false, deferred_volume = m->core->deferred_volume;
+    bool use_ucm = true;
 
     pa_assert(m);
 
@@ -342,14 +700,47 @@ int pa__init(pa_module *m) {
 
     m->userdata = u = pa_xnew0(struct userdata, 1);
     u->core = m->core;
-    u->devices = pa_hashmap_new(pa_idxset_string_hash_func, pa_idxset_string_compare_func);
-    u->use_tsched = TRUE;
+    u->devices = pa_hashmap_new_full(pa_idxset_string_hash_func, pa_idxset_string_compare_func, NULL, (pa_free_cb_t) device_free);
     u->inotify_fd = -1;
 
-    if (pa_modargs_get_value_boolean(ma, "tsched", &u->use_tsched) < 0) {
-        pa_log("Failed to parse tsched argument.");
+    if (pa_modargs_get_value_boolean(ma, "tsched", &use_tsched) < 0) {
+        pa_log("Failed to parse tsched= argument.");
+        goto fail;
+    }
+    u->use_tsched = use_tsched;
+
+    if (pa_modargs_get_value(ma, "tsched_buffer_size", NULL)) {
+        if (pa_modargs_get_value_u32(ma, "tsched_buffer_size", &u->tsched_buffer_size) < 0) {
+            pa_log("Failed to parse tsched_buffer_size= argument.");
+            goto fail;
+        }
+
+        u->tsched_buffer_size_valid = true;
+    }
+
+    if (pa_modargs_get_value_boolean(ma, "fixed_latency_range", &fixed_latency_range) < 0) {
+        pa_log("Failed to parse fixed_latency_range= argument.");
+        goto fail;
+    }
+    u->fixed_latency_range = fixed_latency_range;
+
+    if (pa_modargs_get_value_boolean(ma, "ignore_dB", &ignore_dB) < 0) {
+        pa_log("Failed to parse ignore_dB= argument.");
         goto fail;
     }
+    u->ignore_dB = ignore_dB;
+
+    if (pa_modargs_get_value_boolean(ma, "deferred_volume", &deferred_volume) < 0) {
+        pa_log("Failed to parse deferred_volume= argument.");
+        goto fail;
+    }
+    u->deferred_volume = deferred_volume;
+
+    if (pa_modargs_get_value_boolean(ma, "use_ucm", &use_ucm) < 0) {
+        pa_log("Failed to parse use_ucm= argument.");
+        goto fail;
+    }
+    u->use_ucm = use_ucm;
 
     if (!(u->udev = udev_new())) {
         pa_log("Failed to initialize udev library.");
@@ -364,12 +755,17 @@ int pa__init(pa_module *m) {
         goto fail;
     }
 
+    if (udev_monitor_filter_add_match_subsystem_devtype(u->monitor, "sound", NULL) < 0) {
+        pa_log("Failed to subscribe to sound devices.");
+        goto fail;
+    }
+
     errno = 0;
     if (udev_monitor_enable_receiving(u->monitor) < 0) {
         pa_log("Failed to enable monitor: %s", pa_cstrerror(errno));
         if (errno == EPERM)
             pa_log_info("Most likely your kernel is simply too old and "
-                        "allows only priviliged processes to listen to device events. "
+                        "allows only privileged processes to listen to device events. "
                         "Please upgrade your kernel to at least 2.6.30.");
         goto fail;
     }
@@ -402,7 +798,7 @@ int pa__init(pa_module *m) {
 
     udev_enumerate_unref(enumerate);
 
-    pa_log_info("Loaded %u modules.", pa_hashmap_size(u->devices));
+    pa_log_info("Found %u cards.", pa_hashmap_size(u->devices));
 
     pa_modargs_free(ma);
 
@@ -444,14 +840,8 @@ void pa__done(pa_module *m) {
     if (u->inotify_fd >= 0)
         pa_close(u->inotify_fd);
 
-    if (u->devices) {
-        struct device *d;
-
-        while ((d = pa_hashmap_steal_first(u->devices)))
-            device_free(d);
-
-        pa_hashmap_free(u->devices, NULL, NULL);
-    }
+    if (u->devices)
+        pa_hashmap_free(u->devices);
 
     pa_xfree(u);
 }