On Mar 25, 2024, at 00:51, Lexi Winter <l...@le-fay.org> wrote: > Lexi Winter: >> . . . > > . . . > > - even with the working keyboard, ctrl+alt+esc doesn't seem to work to > break into kdb when the problem occurs. i'm not sure if i'm doing > something wrong here or that key sequence doesn't work over USB, so i > wanted to try it via a serial console instead, which led to... > > . . .
https://man.freebsd.org/cgi/man.cgi?ddb(4) reports: QUOTE Serial consoles can break to the debugger by sending a BREAK condition on the serial line. This requires a kernel built with options BREAK_TO_DEBUGGER is specified in the kernel. Most terminal emulation programs can send a break sequence with a special key sequence or menu selection. Sending the break can be difficult or even happen spuri- ously in some setups. An alternative method is to build a kernel with options ALT_BREAK_TO_DEBUGGER then the sequence of CR TILDE CTRL-B en- ters the debugger; CR TILDE CTRL-P causes a panic; and CR TILDE CTRL-R causes an immediate reboot. In all these sequences, CR represents Car- riage Return and is usually sent by pressing the Enter or Return key. TILDE is the ASCII tilde character (~). CTRL-x is Control x, sent by pressing the Control key, then x, then releasing both. END QUOTE Note the lack of mention of the ctrl+alt+esc . I expect that the: https://docs.freebsd.org/en/books/developers-handbook/kerneldebug/ reference to "The default break-to-debugger sequence is Ctrl+Alt+ESC" may be x86/i386 specific (historical tier 1) or have some other specific type of context it applies to. I've historically used ALT_BREAK_TO_DEBUGGER and its CR TILDE CTRL-B on everything to get to the ddb> prompt via keyboards, including the serial console. (But, thinking about it, I've not used that in some time.) === Mark Millard marklmi at yahoo.com
