Index: share/man/man4/ddb.4 =================================================================== --- share/man/man4/ddb.4 +++ share/man/man4/ddb.4 @@ -1538,41 +1538,39 @@ combination with .Nm . .Pp -For serial consoles, you can enter the debugger by sending a BREAK -condition on the serial line if +Serial consoles can break to the debugger by sending a BREAK +condition on the serial line. +This requires a kernel built with .Cd options BREAK_TO_DEBUGGER is specified in the kernel. Most terminal emulation programs can send a break sequence with a -special key sequence or via a menu item. -However, in some setups, sending the break can be difficult to arrange -or happens spuriously, so if the kernel contains +special key sequence or menu selection. +Sending the break can be difficult or even happen spuriously in some setups. +An alternative method is to build a kernel with .Cd options ALT_BREAK_TO_DEBUGGER then the sequence of CR TILDE CTRL-B enters the debugger; -CR TILDE CTRL-P causes a panic instead of entering the -debugger; and +CR TILDE CTRL-P causes a panic; and CR TILDE CTRL-R causes an immediate reboot. -In all the above sequences, CR is a Carriage Return and is usually -sent by hitting the Enter or Return key. +In all these sequences, CR represents Carriage Return and is usually +sent by pressing the Enter or Return key. TILDE is the ASCII tilde character (~). -CTRL-x is Control x created by hitting the control key and then x +CTRL-x is Control x, send by pressing the Control key, then x, then releasing both. and then releasing both. .Pp -The break to enter the debugger behavior may be enabled at run-time -by setting the +The break-to-debugger behavior can be enabled by setting .Xr sysctl 8 .Va debug.kdb.break_to_debugger to 1. -The alternate sequence to enter the debugger behavior may be enabled -at run-time by setting the +The alt-break-to-debugger behavior can be enabled by setting .Xr sysctl 8 .Va debug.kdb.alt_break_to_debugger to 1. -The debugger may be entered by setting the +The debugger can be entered by setting .Xr sysctl 8 .Va debug.kdb.enter to 1. .Pp -Output may be interrupted, paused, and resumed with the control +Output can be interrupted, paused, and resumed with the control characters CTRL-C, CTRL-S, and CTRL-Q. Because these control characters are received as in-band data from the console, there is an input buffer, and once that buffer fills