safe. knote_locked(9) will not grab kernel lock, so call it directly from
interrupt handlers instead of scheduling software interrupts.
feedback and ok ratchov
selwakeup() needs to be protected by KERNEL_LOCK, but we're not
allowed to grab KERNEL_LOCK on interrupt context because midi runs at
IPL_AUDIO with the audio_lock held. Furthermore, doing so is a locking
order bug: syscall code-path grabs KERNEL_LOCK first while interrupt
code-path does the opposite when calling selwakeup().
ok visa
the preferred method to access MIDI hardware is through sndiod(8) which
doesn't use it.
Fixes a potential issue with a stale struct proc pointer found by Ilja van
Sprundel.
ok deraadt@, ratchov@
maintaining a "dying" flag which is already present in the device
structure. As a side-effect, this adds the missing refcounting
that mididetach() was missing. With from mpi@ and dlg@
ok mpi
just return and make the midi(4) driver retry later. UART buffers
are large enough for this, except eap(4) which uses interrupts for
output.
help from and ok jsg@
