Rockbox open source high quality audio player as a Music Player Daemon
mpris
rockbox
mpd
libadwaita
audio
rust
zig
deno
FS#13836 - Remove the pcm sink_mutex to unbreak usb_dac mode
The purpose of the mutex is to make it possible to switch pcm sinks
safely, but pcm_play_lock/unlock and pcm_set_frequency need to be
called from IRQ context which is fundamentally incompatible with
our mutex implementation.
The proper path forward will be to promote the counter-based per-sink
lock/unlock implementation to the pcm core, and only allowing sink
switching when the counter is 0.
In the mean time, just remove sink_mutex entirely as the sink switching
code has yet to be committed.
Change-Id: I029459d7ec6ea47c6e2b8fce52d203129a282832
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firmware/pcm.c
-9
firmware/pcm.c
···
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[PCM_SINK_BUILTIN] = &builtin_pcm_sink,
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};
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static enum pcm_sink_ids cur_sink = PCM_SINK_BUILTIN;
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static struct mutex sink_mutex; /* protects sinks and cur_sink */
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/* The registered callback function to ask for more mp3 data */
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volatile pcm_play_callback_type
···
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*/
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void pcm_play_lock(void) {
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mutex_lock(&sink_mutex);
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sinks[cur_sink]->ops.lock();
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/* hold sink_mutex until pcm_play_unlock() */
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}
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void pcm_play_unlock(void) {
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sinks[cur_sink]->ops.unlock();
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mutex_unlock(&sink_mutex);
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}
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/* This should only be called at startup before any audio playback or
···
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{
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logf("pcm_init");
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mutex_init(&sink_mutex);
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for(size_t i = 0; i < ARRAYLEN(sinks); i += 1) {
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sinks[i]->pending_freq = sinks[i]->caps.default_freq;
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sinks[i]->configured_freq = -1UL;
···
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samplerate = pcm_sampr_to_hw_sampr(samplerate, type);
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#endif /* CONFIG_SAMPR_TYPES */
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mutex_lock(&sink_mutex);
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struct pcm_sink* sink = sinks[cur_sink];
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index = round_value_to_list32(samplerate, sink->caps.samprs, sink->caps.num_samprs, false);
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···
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index = sink->caps.default_freq; /* Invalid = default */
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sink->pending_freq = index;
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mutex_unlock(&sink_mutex);
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}
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/* return last-set frequency */
···
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pcm_wait_for_init();
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mutex_lock(&sink_mutex);
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struct pcm_sink* sink = sinks[cur_sink];
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if(sink->pending_freq != sink->configured_freq) {
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logf(" sink->set_freq");
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sink->ops.set_freq(sink->pending_freq);
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sink->configured_freq = sink->pending_freq;
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}
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mutex_unlock(&sink_mutex);
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}
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#ifdef HAVE_RECORDING