From f05c1ffc274516ef101d2e0f860bcb9b08c6c622 Mon Sep 17 00:00:00 2001 From: Jaroslav Kysela Date: Tue, 25 Jun 2024 19:25:46 +0200 Subject: ALSA: pcm: reinvent the stream synchronization ID API Until the commit e11f0f90a626 ("ALSA: pcm: remove SNDRV_PCM_IOCTL1_INFO internal command"), there was a possibility to pass information about the synchronized streams to the user space. The mentioned commit removed blindly the appropriate code with an irrelevant comment. The revert may be appropriate, but since this API was lost for several years without any complains, it's time to improve it. The hardware parameters may change the used stream clock source (e.g. USB hardware) so move this synchronization ID to hw_params as read-only field. It seems that pipewire can benefit from this API (disable adaptive resampling for perfectly synchronized PCM streams) now. Note that the contents of ID is not supposed to be used for direct comparison with a specific byte sequence. The "empty" case is when all bytes are zero (driver does not offer this information) and all other cases must be only used for equal comparison among PCM streams (including different sound cards) if they are using identical hardware clock. Cc: Takashi Sakamoto Signed-off-by: Jaroslav Kysela Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20240625172836.589380-2-perex@perex.cz --- include/uapi/sound/asound.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'include/uapi') diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index 628d46a0da92..8bf7e8a0eb6f 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -142,7 +142,7 @@ struct snd_hwdep_dsp_image { * * *****************************************************************************/ -#define SNDRV_PCM_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 17) +#define SNDRV_PCM_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 18) typedef unsigned long snd_pcm_uframes_t; typedef signed long snd_pcm_sframes_t; @@ -334,7 +334,7 @@ union snd_pcm_sync_id { unsigned char id[16]; unsigned short id16[8]; unsigned int id32[4]; -}; +} __attribute__((deprecated)); struct snd_pcm_info { unsigned int device; /* RO/WR (control): device number */ @@ -348,7 +348,7 @@ struct snd_pcm_info { int dev_subclass; /* SNDRV_PCM_SUBCLASS_* */ unsigned int subdevices_count; unsigned int subdevices_avail; - union snd_pcm_sync_id sync; /* hardware synchronization ID */ + unsigned char pad1[16]; /* was: hardware synchronization ID */ unsigned char reserved[64]; /* reserved for future... */ }; @@ -420,7 +420,8 @@ struct snd_pcm_hw_params { unsigned int rate_num; /* R: rate numerator */ unsigned int rate_den; /* R: rate denominator */ snd_pcm_uframes_t fifo_size; /* R: chip FIFO size in frames */ - unsigned char reserved[64]; /* reserved for future */ + unsigned char sync[16]; /* R: synchronization ID (perfect sync - one clock source) */ + unsigned char reserved[48]; /* reserved for future */ }; enum { -- cgit v1.2.3 From fefbbdfb59d3a20fd98734363e6dd9fa7cc65c70 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 5 Jul 2024 18:03:42 +0200 Subject: ALSA: seq: Add tempo base unit for MIDI2 Set Tempo messages MIDI2 Set Tempo message defines the tempo in 10ns unit for finer accuracy, while MIDI1 was defined in 1us unit. For adapting this different unit, introduce "tempo_base" field to snd_seq_queue_tempo struct so that user-space can pass the proper tempo base unit. The accepted value is limited, it must be either 0, 10 or 1000. The protocol version is bumped to 1.0.4 along with this. The access with the older protocol version ignores the tempo-base value in ioctls and always treats as 1000. Reviewed-by: Jaroslav Kysela Link: https://patch.msgid.link/20240705160344.6481-1-tiwai@suse.de Signed-off-by: Takashi Iwai --- include/uapi/sound/asequencer.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'include/uapi') diff --git a/include/uapi/sound/asequencer.h b/include/uapi/sound/asequencer.h index c85fdd8895d8..39b37edcf813 100644 --- a/include/uapi/sound/asequencer.h +++ b/include/uapi/sound/asequencer.h @@ -10,7 +10,7 @@ #include /** version of the sequencer */ -#define SNDRV_SEQ_VERSION SNDRV_PROTOCOL_VERSION(1, 0, 3) +#define SNDRV_SEQ_VERSION SNDRV_PROTOCOL_VERSION(1, 0, 4) /** * definition of sequencer event types @@ -523,11 +523,12 @@ struct snd_seq_queue_status { /* queue tempo */ struct snd_seq_queue_tempo { int queue; /* sequencer queue */ - unsigned int tempo; /* current tempo, us/tick */ + unsigned int tempo; /* current tempo, us/tick (or different time-base below) */ int ppq; /* time resolution, ticks/quarter */ unsigned int skew_value; /* queue skew */ unsigned int skew_base; /* queue skew base */ - char reserved[24]; /* for the future */ + unsigned short tempo_base; /* tempo base in nsec unit; either 10 or 1000 */ + char reserved[22]; /* for the future */ }; -- cgit v1.2.3