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-rw-r--r--src/mixer/plugins/AlsaMixerPlugin.cxx357
1 files changed, 357 insertions, 0 deletions
diff --git a/src/mixer/plugins/AlsaMixerPlugin.cxx b/src/mixer/plugins/AlsaMixerPlugin.cxx
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+++ b/src/mixer/plugins/AlsaMixerPlugin.cxx
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+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "mixer/MixerInternal.hxx"
+#include "mixer/Listener.hxx"
+#include "output/OutputAPI.hxx"
+#include "event/MultiSocketMonitor.hxx"
+#include "event/DeferredMonitor.hxx"
+#include "event/Loop.hxx"
+#include "util/ASCII.hxx"
+#include "util/ReusableArray.hxx"
+#include "util/Clamp.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+#include "Log.hxx"
+
+#include <algorithm>
+
+#include <alsa/asoundlib.h>
+
+#define VOLUME_MIXER_ALSA_DEFAULT "default"
+#define VOLUME_MIXER_ALSA_CONTROL_DEFAULT "PCM"
+static constexpr unsigned VOLUME_MIXER_ALSA_INDEX_DEFAULT = 0;
+
+class AlsaMixerMonitor final : MultiSocketMonitor, DeferredMonitor {
+ snd_mixer_t *mixer;
+
+ ReusableArray<pollfd> pfd_buffer;
+
+public:
+ AlsaMixerMonitor(EventLoop &_loop, snd_mixer_t *_mixer)
+ :MultiSocketMonitor(_loop), DeferredMonitor(_loop),
+ mixer(_mixer) {
+ DeferredMonitor::Schedule();
+ }
+
+private:
+ virtual void RunDeferred() override {
+ InvalidateSockets();
+ }
+
+ virtual int PrepareSockets() override;
+ virtual void DispatchSockets() override;
+};
+
+class AlsaMixer final : public Mixer {
+ EventLoop &event_loop;
+
+ const char *device;
+ const char *control;
+ unsigned int index;
+
+ snd_mixer_t *handle;
+ snd_mixer_elem_t *elem;
+ long volume_min;
+ long volume_max;
+ int volume_set;
+
+ AlsaMixerMonitor *monitor;
+
+public:
+ AlsaMixer(EventLoop &_event_loop, MixerListener &_listener)
+ :Mixer(alsa_mixer_plugin, _listener),
+ event_loop(_event_loop) {}
+
+ virtual ~AlsaMixer();
+
+ void Configure(const config_param &param);
+ bool Setup(Error &error);
+
+ /* virtual methods from class Mixer */
+ virtual bool Open(Error &error) override;
+ virtual void Close() override;
+ virtual int GetVolume(Error &error) override;
+ virtual bool SetVolume(unsigned volume, Error &error) override;
+};
+
+static constexpr Domain alsa_mixer_domain("alsa_mixer");
+
+int
+AlsaMixerMonitor::PrepareSockets()
+{
+ if (mixer == nullptr) {
+ ClearSocketList();
+ return -1;
+ }
+
+ int count = snd_mixer_poll_descriptors_count(mixer);
+ if (count < 0)
+ count = 0;
+
+ struct pollfd *pfds = pfd_buffer.Get(count);
+
+ count = snd_mixer_poll_descriptors(mixer, pfds, count);
+ if (count < 0)
+ count = 0;
+
+ ReplaceSocketList(pfds, count);
+ return -1;
+}
+
+void
+AlsaMixerMonitor::DispatchSockets()
+{
+ assert(mixer != nullptr);
+
+ int err = snd_mixer_handle_events(mixer);
+ if (err < 0) {
+ FormatError(alsa_mixer_domain,
+ "snd_mixer_handle_events() failed: %s",
+ snd_strerror(err));
+
+ if (err == -ENODEV) {
+ /* the sound device was unplugged; disable
+ this GSource */
+ mixer = nullptr;
+ InvalidateSockets();
+ return;
+ }
+ }
+}
+
+/*
+ * libasound callbacks
+ *
+ */
+
+static int
+alsa_mixer_elem_callback(snd_mixer_elem_t *elem, unsigned mask)
+{
+ AlsaMixer &mixer = *(AlsaMixer *)
+ snd_mixer_elem_get_callback_private(elem);
+
+ if (mask & SND_CTL_EVENT_MASK_VALUE) {
+ int volume = mixer.GetVolume(IgnoreError());
+ mixer.listener.OnMixerVolumeChanged(mixer, volume);
+ }
+
+ return 0;
+}
+
+/*
+ * mixer_plugin methods
+ *
+ */
+
+inline void
+AlsaMixer::Configure(const config_param &param)
+{
+ device = param.GetBlockValue("mixer_device",
+ VOLUME_MIXER_ALSA_DEFAULT);
+ control = param.GetBlockValue("mixer_control",
+ VOLUME_MIXER_ALSA_CONTROL_DEFAULT);
+ index = param.GetBlockValue("mixer_index",
+ VOLUME_MIXER_ALSA_INDEX_DEFAULT);
+}
+
+static Mixer *
+alsa_mixer_init(EventLoop &event_loop, gcc_unused AudioOutput &ao,
+ MixerListener &listener,
+ const config_param &param,
+ gcc_unused Error &error)
+{
+ AlsaMixer *am = new AlsaMixer(event_loop, listener);
+ am->Configure(param);
+
+ return am;
+}
+
+AlsaMixer::~AlsaMixer()
+{
+ /* free libasound's config cache */
+ snd_config_update_free_global();
+}
+
+gcc_pure
+static snd_mixer_elem_t *
+alsa_mixer_lookup_elem(snd_mixer_t *handle, const char *name, unsigned idx)
+{
+ for (snd_mixer_elem_t *elem = snd_mixer_first_elem(handle);
+ elem != nullptr; elem = snd_mixer_elem_next(elem)) {
+ if (snd_mixer_elem_get_type(elem) == SND_MIXER_ELEM_SIMPLE &&
+ StringEqualsCaseASCII(snd_mixer_selem_get_name(elem),
+ name) &&
+ snd_mixer_selem_get_index(elem) == idx)
+ return elem;
+ }
+
+ return nullptr;
+}
+
+inline bool
+AlsaMixer::Setup(Error &error)
+{
+ int err;
+
+ if ((err = snd_mixer_attach(handle, device)) < 0) {
+ error.Format(alsa_mixer_domain, err,
+ "failed to attach to %s: %s",
+ device, snd_strerror(err));
+ return false;
+ }
+
+ if ((err = snd_mixer_selem_register(handle, nullptr,
+ nullptr)) < 0) {
+ error.Format(alsa_mixer_domain, err,
+ "snd_mixer_selem_register() failed: %s",
+ snd_strerror(err));
+ return false;
+ }
+
+ if ((err = snd_mixer_load(handle)) < 0) {
+ error.Format(alsa_mixer_domain, err,
+ "snd_mixer_load() failed: %s\n",
+ snd_strerror(err));
+ return false;
+ }
+
+ elem = alsa_mixer_lookup_elem(handle, control, index);
+ if (elem == nullptr) {
+ error.Format(alsa_mixer_domain, 0,
+ "no such mixer control: %s", control);
+ return false;
+ }
+
+ snd_mixer_selem_get_playback_volume_range(elem, &volume_min,
+ &volume_max);
+
+ snd_mixer_elem_set_callback_private(elem, this);
+ snd_mixer_elem_set_callback(elem, alsa_mixer_elem_callback);
+
+ monitor = new AlsaMixerMonitor(event_loop, handle);
+
+ return true;
+}
+
+inline bool
+AlsaMixer::Open(Error &error)
+{
+ int err;
+
+ volume_set = -1;
+
+ err = snd_mixer_open(&handle, 0);
+ if (err < 0) {
+ error.Format(alsa_mixer_domain, err,
+ "snd_mixer_open() failed: %s", snd_strerror(err));
+ return false;
+ }
+
+ if (!Setup(error)) {
+ snd_mixer_close(handle);
+ return false;
+ }
+
+ return true;
+}
+
+inline void
+AlsaMixer::Close()
+{
+ assert(handle != nullptr);
+
+ delete monitor;
+
+ snd_mixer_elem_set_callback(elem, nullptr);
+ snd_mixer_close(handle);
+}
+
+inline int
+AlsaMixer::GetVolume(Error &error)
+{
+ int err;
+ int ret;
+ long level;
+
+ assert(handle != nullptr);
+
+ err = snd_mixer_handle_events(handle);
+ if (err < 0) {
+ error.Format(alsa_mixer_domain, err,
+ "snd_mixer_handle_events() failed: %s",
+ snd_strerror(err));
+ return false;
+ }
+
+ err = snd_mixer_selem_get_playback_volume(elem,
+ SND_MIXER_SCHN_FRONT_LEFT,
+ &level);
+ if (err < 0) {
+ error.Format(alsa_mixer_domain, err,
+ "failed to read ALSA volume: %s",
+ snd_strerror(err));
+ return false;
+ }
+
+ ret = ((volume_set / 100.0) * (volume_max - volume_min)
+ + volume_min) + 0.5;
+ if (volume_set > 0 && ret == level) {
+ ret = volume_set;
+ } else {
+ ret = (int)(100 * (((float)(level - volume_min)) /
+ (volume_max - volume_min)) + 0.5);
+ }
+
+ return ret;
+}
+
+inline bool
+AlsaMixer::SetVolume(unsigned volume, Error &error)
+{
+ float vol;
+ long level;
+ int err;
+
+ assert(handle != nullptr);
+
+ vol = volume;
+
+ volume_set = vol + 0.5;
+
+ level = (long)(((vol / 100.0) * (volume_max - volume_min) +
+ volume_min) + 0.5);
+ level = Clamp(level, volume_min, volume_max);
+
+ err = snd_mixer_selem_set_playback_volume_all(elem, level);
+ if (err < 0) {
+ error.Format(alsa_mixer_domain, err,
+ "failed to set ALSA volume: %s",
+ snd_strerror(err));
+ return false;
+ }
+
+ return true;
+}
+
+const MixerPlugin alsa_mixer_plugin = {
+ alsa_mixer_init,
+ true,
+};