From 275409fee3452e110fd4e21a1f0dadf4923c1d6e Mon Sep 17 00:00:00 2001 From: Kai Vehmanen Date: Fri, 29 May 2020 15:28:16 +0300 Subject: [PATCH] pcm: add documentation for -ENODATA error code This error code can be used e.g. with echo reference PCM devices (the SND_USE_CASE_MOD_ECHO_REF UCM token). Signed-off-by: Kai Vehmanen --- src/pcm/pcm.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c index 98b5ced4..45e791b7 100644 --- a/src/pcm/pcm.c +++ b/src/pcm/pcm.c @@ -292,6 +292,14 @@ This error can happen when device is physically removed (for example some hotplug devices like USB or PCMCIA, CardBus or ExpressCard can be removed on the fly). +\par -ENODATA + +This error can happen if the device data transfer is dependent on +an external condition and that condition is not met. For example, +PCM device for echo reference as described by SND_USE_CASE_MOD_ECHO_REF +UCM token, may return -ENODATA if the linked playback stream has not been +started. + \section pcm_params Managing parameters The ALSA PCM device uses two groups of PCM related parameters. The hardware -- 2.47.1