CVSROOT: /cvs
Module name: src
Changes by: [email protected] 2019/12/22 12:11:45
Modified files:
sys/dev : midi.c
Log message:
midi(4): *sleep(9) -> *sleep_nsec(9)
These are straightforward except for the tsleep(9) conversion. ratchov@
had a bit to say about that code:
https://marc.info/?l=openbsd-tech&m=157665936017373&w=2
> The problem is that close(2) may reset the transmitter before the few
> bytes of its internal buffer is sent on the wire; there's no "wait for
> completion" feature in such simple hardware, so we just wait few
> milliseconds.
>
> The transmitter buffer size is around 16 bytes, the byte rate is 3125
> bytes/second. So if we wait at least 16B / 3125B/s = 5.12ms, we're
> safe. Waiting 10ms-20ms is enough and is unnoticeable.
Hence, in this diff we wait a flat 20ms in that situation.
ok ratchov@
