Lines Matching +full:key +full:- +full:press
1 Linux Magic System Request Key Hacks
6 What is the magic SysRq key?
9 It is a 'magical' key combo you can hit which the kernel will respond to
12 How do I enable the magic SysRq key?
15 You need to say "yes" to 'Magic SysRq key (CONFIG_MAGIC_SYSRQ)' when
18 the SysRq key. The default value in this file is set by the
22 - 0 - disable sysrq completely
23 - 1 - enable all functions of sysrq
24 - >1 - bitmask of allowed sysrq functions (see below for detailed function
27 2 = 0x2 - enable control of console logging level
28 4 = 0x4 - enable control of keyboard (SAK, unraw)
29 8 = 0x8 - enable debugging dumps of processes etc.
30 16 = 0x10 - enable sync command
31 32 = 0x20 - enable remount read-only
32 64 = 0x40 - enable signalling of processes (term, kill, oom-kill)
33 128 = 0x80 - allow reboot/poweroff
34 256 = 0x100 - allow nicing of all RT tasks
45 via a keyboard. Invocation of any operation via ``/proc/sysrq-trigger`` is
48 How do I use the magic SysRq key?
52 You press the key combo :kbd:`ALT-SysRq-<command key>`.
56 keyboards may not have a key labeled 'SysRq'. The 'SysRq' key is
57 also known as the 'Print Screen' key. Also some keyboards cannot
59 have better luck with press :kbd:`Alt`, press :kbd:`SysRq`,
60 release :kbd:`SysRq`, press :kbd:`<command key>`, release everything.
63 You press :kbd:`ALT-STOP-<command key>`, I believe.
66 You send a ``BREAK``, then within 5 seconds a command key. Sending
70 Press :kbd:`ALT - Print Screen` (or :kbd:`F13`) - :kbd:`<command key>`.
71 :kbd:`Print Screen` (or :kbd:`F13`) - :kbd:`<command key>` may suffice.
74 If you know of the key combos for other architectures, please
78 Write a character to /proc/sysrq-trigger. e.g.::
80 echo t > /proc/sysrq-trigger
82 The :kbd:`<command key>` is case sensitive.
105 ``h`` Will display help (actually any other key than those listed
106 here will display help. but ``h`` is easy to remember :-)
110 ``j`` Forcibly "Just thaw it" - filesystems frozen by the FIFREEZE ioctl.
112 ``k`` Secure Access Key (SAK) Kills all programs on the current virtual
119 ``n`` Used to make RT tasks nice-able
136 ``u`` Will attempt to remount all mounted filesystems read-only.
139 ``v`` Causes ETM buffer dump [ARM-specific]
147 ``y`` Show global CPU Registers [SPARC-64 specific]
151 ``0``-``9`` Sets the console log level, controlling which kernel messages
162 sak(k) (Secure Access Key) is useful when you want to be sure there is no
174 It seems others find it useful as (System Attention Key) which is
185 shell that provides no graceful shutdown -- it will ensure your data is
190 running system's point of view, they will be remounted read-only. The remount
193 The loglevels ``0``-``9`` are useful when your console is being flooded with
210 :kbd:`alt-sysrq-z`).
219 pre-defined value of 99
220 (see ``KEY_SYSRQ`` in ``include/uapi/linux/input-event-codes.h``), or
221 which don't have a SysRq key at all. In these cases, run ``showkey -s`` to find
227 I want to add SysRQ key events to a module, how does it work?
232 Next, you must create a ``sysrq_key_op`` struct, and populate it with A) the key
238 ``register_sysrq_key(int key, const struct sysrq_key_op *op_p);`` this will
239 register the operation pointed to by ``op_p`` at table key 'key',
241 the function ``unregister_sysrq_key(int key, const struct sysrq_key_op *op_p)``,
242 which will remove the key op pointed to by 'op_p' from the key 'key', if and
246 The Magic SysRQ system works by registering key operations against a key op
247 lookup table, which is defined in 'drivers/tty/sysrq.c'. This key table has
255 unregister_sysrq_key() to clean up the sysrq key table entry that it used.
263 When I hit a SysRq key combination only the header appears on the console?
275 to temporarily up the console loglevel using :kbd:`alt-sysrq-8` or::
277 echo 8 > /proc/sysrq-trigger
285 Just ask them on the linux-kernel mailing list:
286 linux-kernel@vger.kernel.org
291 - Written by Mydraal <vulpyne@vulpyne.net>
292 - Updated by Adam Sulmicki <adam@cfar.umd.edu>
293 - Updated by Jeremy M. Dolan <jmd@turbogeek.org> 2001/01/28 10:15:59
294 - Added to by Crutcher Dunnavant <crutcher+kernel@datastacks.com>