---
- branch: MAIN
  date: Mon Mar 28 12:39:29 UTC 2022
  files:
  - new: '1.300'
    old: '1.299'
    path: src/sys/kern/tty.c
    pathrev: src/sys/kern/tty.c@1.300
    type: modified
  - new: '1.96'
    old: '1.95'
    path: src/sys/sys/tty.h
    pathrev: src/sys/sys/tty.h@1.96
    type: modified
  id: 20220328T123929Z.6656aadbb6aa85b1ef18332103a757e3c1cbbcff
  log: |
    tty(9): New ttycancel function.

    This causes any current and future ttyopens to fail until ttyclose.

    This is necessary for revoke to work reliably for device detach like
    ucom(4) removable USB devices.  A tty driver for a removable device
    needs some way to interrupt a pending .d_open so it returns promptly.
    But ttyclose only interrupts ttyopen if it's already sleeping; it
    won't cause a concurrent .d_open call which _will call_ but _hasn't
    yet called_ ttyopen to avoid sleeping.  Using ttycancel in the tty
    driver's .d_cancel makes this work.
  module: src
  subject: 'CVS commit: src/sys'
  unixtime: '1648471169'
  user: riastradh