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I'm trying to get a login prompt on an embedded system using Debian and systemd. The system is connected via a physical serial console to a host PC. If I start the kernel with the cmdline parameters console=ttyS5,115200 console=tty1 systemd.journald.forward_to_console=1 I do see all the kernel messages from /dev/kmsg and systemd logs, but I never see a login prompt. If I omit console=tty1 the kernel log is still beeing printed, but the systemd logs appear with a 30 seconds timeout for each line.

What's the problem here? The same root file system works just fine for a similar embedded system.

JohnnyFromBF
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    You say it's an embedded system. Is it an x86 system or something else? The name `ttyS5` would indicate that there are 5 other serial ports (`ttyS0` .. `ttyS4`). In a regular x86 system, only up to four classic 8250-compatible serial ports are expected by default; have you made any kernel configuration changes? What is the output of `setserial -g /dev/ttyS*`? If the serial port is not 8250-compatible, is the appropriate hardware support built into the kernel? – telcoM Dec 12 '18 at 14:11
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    You say "If I omit console=tty1 the kernel log is still beeing printed, but the systemd logs appear with a 30 seconds timeout for each line." But do you get a console prompt that way? The 30s delay, is it really for *each* line? Or does it look like the lines are "batched" together, so you get multiple lines at once every so often? – filbranden Dec 12 '18 at 14:35
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    Also posted at: https://github.com/systemd/systemd/issues/11133 – filbranden Dec 12 '18 at 19:11

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