CVSROOT: /cvs
Module name: src
Changes by: [email protected] 2026/04/26 03:27:15
Modified files:
sys/dev/ic : com.c
Log message:
Attempt to drain the transmit FIFO before resetting or disabling it such
that output that is currently in the FIFO makes it out. We already do
this when attaching as a console by using a fixed delay, but not in
compwroff() which runs when userland closes the associated tty. Instead
of using a fixed delay, look at the LSR_TSRE bit which should get set
if the FIFO (or the itransmit shift register if the FIFO is disabled) is
empty. Use a fixed timeout such that on hardware with a non-functional
LSR_TSRE bit the loops still terminate.
This should fix issues where we lose serial output when userland closes
a tty or when com(4) attaches to the port that is used as the console.
ok deraadt@
