From 979f26d8578055b7846559c0f36da6b1f475307a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20M=C3=BCller?= Date: Sat, 22 Oct 2022 22:19:18 -0700 Subject: [PATCH] Work around snd_pcm_poll_descriptors argument check issue MPD does not work properly with bluez-alsa driven Bluetooth devices, at least not in certain configurations. In those it emits the following error: > output: Failed to play on "XXX" (alsa): snd_pcm_poll_descriptors() failed: Invalid argument > exception: Failed to open audio output The reason seems to be that MPD makes certain assumptions about some poll file descriptor array that bluez-alsa receives (though ALSA callbacks) but disagrees with. The alsa-lib API supposedly has the contract under specified. If you feel like having a bit more life juice drained out of you, you are encouraged to read up on the circus here: https://github.com/Arkq/bluez-alsa/issues/174 https://github.com/MusicPlayerDaemon/MPD/issues/432 https://github.com/MusicPlayerDaemon/MPD/issues/548 https://github.com/MusicPlayerDaemon/MPD/issues/1037 https://github.com/MusicPlayerDaemon/MPD/issues/1204 This change works around the issue by ignoring the return value of the call to ba_dbus_connection_poll_fds from within bluealsa_poll_descriptors, which is the PCM devices poll_descriptors handler. Better than no sound... --- src/asound/bluealsa-pcm.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/src/asound/bluealsa-pcm.c b/src/asound/bluealsa-pcm.c index 4538ab..d269f7 100644 --- a/src/asound/bluealsa-pcm.c +++ b/src/asound/bluealsa-pcm.c @@ -1024,8 +1024,7 @@ static int bluealsa_poll_descriptors(snd_pcm_ioplug_t *io, struct pollfd *pfd, return -EINVAL; nfds_t dbus_nfds = nfds - 1; - if (!ba_dbus_connection_poll_fds(&pcm->dbus_ctx, &pfd[1], &dbus_nfds)) - return -EINVAL; + (void)ba_dbus_connection_poll_fds(&pcm->dbus_ctx, &pfd[1], &dbus_nfds); /* PCM plug-in relies on our internal event file descriptor. */ pfd[0].fd = pcm->event_fd; -- 2.45.2