Hot answers tagged magic-sysrq
I found the solution myself just after asking this question. To switch back the console in which X is running (usually tty7), from ASCII mode to RAW mode execute the following command: sudo kbd_mode -s -C /dev/tty7 And now everything works as expected again. :) More information available in the question: What does raw/unraw keyboard mode mean?
When you press a key on your keyboard, it sends a numeric code to the computer, called a scan code. The scan code tells the computer which key was pressed; for example, on a typical US keyboard, the A key sends the scan code 30 when you press it (and 158 when you release it). The keyboard driver reports these codes directly to applications when the keyboard ...
You can define which type of code your keyboard sends. This is done via the keyboard mode. You can change the mode of a keyboard with kbd_mode. These are the options from the manpage: -s: scancode mode (RAW), -k: keycode mode (MEDIUMRAW), -a: ASCII mode (XLATE), -u: UTF-8 mode (UNICODE). Its much easier for a developer to catch key events ...
Assuming you have a kernel with the debugger option compiled in you can use ControlAltEscape. From there you can call boot(0) or panic. Chapter 10 of the FreeBSD developers handbook explains this in a lot more detail. So much for more or less the same as SysReq via a keyboard. On the serial console, you need to send the break signal and have the options ...
On a typical laptop, you need to press the Fn key to press SysRq. If you also press the letter in the same movement, you end up pressing Fn+Alt+SysRq+letter. But several letters are mapped to numeric keypad keys when combined with Fn. For example, if you try to press Alt+SysRq+U, you end up pressing Alt+SysRq+Num4 instead. To avoid this pitfall, press and ...
Apparently, it can be enabled/disabled using /proc/sys/kernel/sysrq if the kernel supports it, i.e., CONFIG_MAGIC_SYSRQ is enabled in the kernel config what should be the case for Slackware, according to this.
Forget about REISUB. I don't know who invented this, but it's overly complicated: half the steps are junk. If you're going to unmount and reboot, you only need two steps: U and B. At most three steps E, U, B. Alt+SysRq+R resets the keyboard mode to cooked mode (where typing a character inserts that character). That's useful if a program died and left the ...
Here you go. It's in the kernel mainline, selectable by config. Basically, sysrq enables/disables the physical magic, the others are for programmed control. The doc's pretty straightforward.
Only top voted, non community-wiki answers of a minimum length are eligible