[systemd-devel] Serial console flow control will stuck systemd

[细石泉]

systemd will write log to console directly when bootup. A unexpected serial
console flow control maybe block systemd at embedded systems. I guess
systemd doesn't do a good job of initializing the serial console.
If a noise XOFF(HEX13) generate when systemd bootup, systemd stucked.
Should systemd turn off any flow control stuff when initializing the serial
console?