ALSA: rawmidi: Add framing mode

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This commit adds a new framing mode that frames all MIDI data into
32-byte frames with a timestamp.

The main benefit is that we can get accurate timestamps even if
userspace wakeup and processing is not immediate.

Testing on a Celeron N3150 with this mode has a max jitter of 2.8 ms,
compared to the in-kernel seq implementation which has a max jitter
of 5 ms during idle and much worse when running scheduler stress tests
in parallel.

Signed-off-by: David Henningsson <coding@diwic.se>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210515071533.55332-1-coding@diwic.se
Signed-off-by: Takashi Iwai <tiwai@suse.de>

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David Henningsson 2021-05-15 09:15:33 +02:00 • committed by Takashi Iwai

parent bac5905454

commit 08fdced60c

4 changed files with 124 additions and 5 deletions

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include/uapi/sound/asound.h

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