[alsa-devel] [PATCH v2 00/10] audio timestamping evolutions
Jaroslav Kysela
perex at perex.cz
Fri Dec 19 21:38:41 CET 2014
Dne 19.12.2014 v 18:25 Pierre-Louis Bossart napsal(a):
> This series of patches was inspired by recent threads on the alsa
> mailing list, as well issues detected with existing and upcoming
> hardware:
I don't like some aspects in the interface:
1) ext_info member is not required - the standard info field
has enough free bits
2) the whole struct snd_pcm_status is R/O -
_IOR('A', 0x20, struct snd_pcm_status); I believe that it's much
better to add new audio_tstamp_type to sw_params, but see (4)
3) accuracy - I would use uint64_t and report accuracy in pico-seconds
(range from 0 picoseconds to 18446744 seconds); yes, use next bytes
from the reserved part of status struct. the __u32 might be used only
for flags
4) if there is a motivation to call / obtain timestamps for multiple
purposes (audio tstamp types), then offer to return all these
timestamps in one shot rather than do multiple queries (again, use
reserved bytes)
Thanks,
Jaroslav
--
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project; Red Hat, Inc.
More information about the Alsa-devel
mailing list