---
- branch: MAIN
  date: Sat Aug 13 06:47:41 UTC 2022
  files:
  - new: '1.135'
    old: '1.134'
    path: src/sys/dev/audio/audio.c
    pathrev: src/sys/dev/audio/audio.c@1.135
    type: modified
  - new: '1.20'
    old: '1.19'
    path: src/sys/dev/audio/audiodef.h
    pathrev: src/sys/dev/audio/audiodef.h@1.20
    type: modified
  id: 20220813T064741Z.82c9c43956fa2a42754fb85402c2d7ad89ec372c
  log: |
    audio: Rework about usrbuf allocation.
    - Allocate the usrbuf from kmem(9) instead of uvm(9).  The usrbuf has used
      uvm(9), in case mmap(2) might be issued later.  However, despite the most
      apps don't use mmap(2), allocating (and reallocating) uvm(9) every time
      would be expensive.  In addition, uvm(9) for recording usrbuf was totally
      pointless now.
    - For playback, the usrbuf memory will be allocated in pages.  Because the
      usrbuf for playback is mostly near 64KB for backward compatibility.
      This will reduce reallocation especially from the initial ulaw to the most
      commonly used format like slinear16/2ch/48kHz.
    - When mmap(2) is called, it will replace the playback usrbuf from kmem(9) to
      uvm(9).
    - Prohibit changing playback format once mmap(2) is called.
      It follows netbsd-7.
    - For recording, the usrbuf memory will be allocated in the requested size
      every time as before.  Because the usrbuf for recording is only one block
      and is enough small to the page in the most case.
    Inspired by PR kern/56947.
  module: src
  subject: 'CVS commit: src/sys/dev/audio'
  unixtime: '1660373261'
  user: isaki