* Re: [PATCH] Stateful Magic Sysrq Key
@ 2001-10-02 8:48 willy tarreau
2001-10-02 14:18 ` Crutcher Dunnavant
0 siblings, 1 reply; 3+ messages in thread
From: willy tarreau @ 2001-10-02 8:48 UTC (permalink / raw)
To: Ian Stirling, linux-kernel
> I'd suggest either making this behaviour optional,
or making it
> so that hitting alt-sysrq twice, without any other
keys being
> pressed makes the next key stick.
I agree with you that there's a risk. Mike Harris had
written a
patch for 2.2 which did something similar, but
slightly better
IMO since it avoids risks of mis-press, handles
correctly
broken keyboards and keeps compatible with the
existing
method. Basically, it allows the user to press Alt,
then SysRQ,
release SysRQ then press the desired key, and later
release
Alt. In fact, it only resets the "magic-key-mode" flag
after Alt
has been released, and doesn't bother when SysRq is
released.
I don't remember where it was available, but if
someone needs
it, I still have it here for 2.2.
Willy
___________________________________________________________
Do You Yahoo!? -- Un e-mail gratuit @yahoo.fr !
Yahoo! Courrier : http://fr.mail.yahoo.com
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Stateful Magic Sysrq Key
2001-10-02 8:48 [PATCH] Stateful Magic Sysrq Key willy tarreau
@ 2001-10-02 14:18 ` Crutcher Dunnavant
2001-10-03 14:05 ` [PATCH] Stateful Magic Sysrq Key + Sticky Tag Crutcher Dunnavant
0 siblings, 1 reply; 3+ messages in thread
From: Crutcher Dunnavant @ 2001-10-02 14:18 UTC (permalink / raw)
To: linux-kernel
++ 02/10/01 10:48 +0200 - willy tarreau:
> > I'd suggest either making this behaviour optional,
> or making it
> > so that hitting alt-sysrq twice, without any other
> keys being
> > pressed makes the next key stick.
>
> I agree with you that there's a risk. Mike Harris had
> written a
> patch for 2.2 which did something similar, but
> slightly better
> IMO since it avoids risks of mis-press, handles
> correctly
> broken keyboards and keeps compatible with the
> existing
> method. Basically, it allows the user to press Alt,
> then SysRQ,
> release SysRQ then press the desired key, and later
> release
> Alt. In fact, it only resets the "magic-key-mode" flag
> after Alt
> has been released, and doesn't bother when SysRq is
> released.
But this would require that alt be pressed. This is not acceptable on
exactly the sort of boards which require this patch.
I will look at adding a 'sysrq-sticky' entry to proc, which will do the
obvious thing. I think that this should address everyone's concerns.
--
Crutcher <crutcher@datastacks.com>
GCS d--- s+:>+:- a-- C++++$ UL++++$ L+++$>++++ !E PS+++ PE Y+ PGP+>++++
R-(+++) !tv(+++) b+(++++) G+ e>++++ h+>++ r* y+>*$
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] Stateful Magic Sysrq Key + Sticky Tag
2001-10-02 14:18 ` Crutcher Dunnavant
@ 2001-10-03 14:05 ` Crutcher Dunnavant
0 siblings, 0 replies; 3+ messages in thread
From: Crutcher Dunnavant @ 2001-10-03 14:05 UTC (permalink / raw)
To: linux-kernel; +Cc: Linus Torvalds, Alan Cox
[-- Attachment #1: Type: text/plain, Size: 1936 bytes --]
This is the previous stateful sysrq patch, plus a 'sysrq-sticky' proc
entry, which defaults to off, that controls whether the stateful mode
will be used or not.
This reworked patch is against 2.4.11-pre2.
++ 02/10/01 10:18 -0400 - Crutcher Dunnavant:
> ++ 02/10/01 10:48 +0200 - willy tarreau:
> > > I'd suggest either making this behaviour optional,
> > or making it
> > > so that hitting alt-sysrq twice, without any other
> > keys being
> > > pressed makes the next key stick.
> >
> > I agree with you that there's a risk. Mike Harris had
> > written a
> > patch for 2.2 which did something similar, but
> > slightly better
> > IMO since it avoids risks of mis-press, handles
> > correctly
> > broken keyboards and keeps compatible with the
> > existing
> > method. Basically, it allows the user to press Alt,
> > then SysRQ,
> > release SysRQ then press the desired key, and later
> > release
> > Alt. In fact, it only resets the "magic-key-mode" flag
> > after Alt
> > has been released, and doesn't bother when SysRq is
> > released.
>
> But this would require that alt be pressed. This is not acceptable on
> exactly the sort of boards which require this patch.
>
> I will look at adding a 'sysrq-sticky' entry to proc, which will do the
> obvious thing. I think that this should address everyone's concerns.
>
> --
> Crutcher <crutcher@datastacks.com>
> GCS d--- s+:>+:- a-- C++++$ UL++++$ L+++$>++++ !E PS+++ PE Y+ PGP+>++++
> R-(+++) !tv(+++) b+(++++) G+ e>++++ h+>++ r* y+>*$
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
Crutcher <crutcher@datastacks.com>
GCS d--- s+:>+:- a-- C++++$ UL++++$ L+++$>++++ !E PS+++ PE Y+ PGP+>++++
R-(+++) !tv(+++) b+(++++) G+ e>++++ h+>++ r* y+>*$
[-- Attachment #2: patch-2.4.11-pre2-stateful_sticky_sysrq --]
[-- Type: text/plain, Size: 6975 bytes --]
diff -ur linux-2.4.11-pre2/drivers/char/keyboard.c linux-2.4.11-pre2-stateful_sysrq/drivers/char/keyboard.c
--- linux-2.4.11-pre2/drivers/char/keyboard.c Tue Sep 18 16:39:51 2001
+++ linux-2.4.11-pre2-stateful_sysrq/drivers/char/keyboard.c Wed Oct 3 00:15:08 2001
@@ -21,6 +21,12 @@
*
* 27-05-97: Added support for the Magic SysRq Key (Martin Mares)
* 30-07-98: Dead keys redone, aeb@cwi.nl.
+ *
+ * 28-09-2001: Crutcher Dunnavant <crutcher+kernel@datastacks.com>
+ * Add stateful sysrq features, based upon work from:
+ * Mathew Mills <mmills@amazon.com>
+ * Norman Murray <nmurray@redhat.com>
+ *
*/
#include <linux/config.h>
@@ -157,7 +163,14 @@
struct pt_regs * kbd_pt_regs;
#ifdef CONFIG_MAGIC_SYSRQ
-static int sysrq_pressed;
+static enum {
+ UP_AND_CLEAR,
+ DOWN_AND_WAITING,
+ DOWN_AND_DONE,
+ UP_AND_WAITING,
+ DOWN_AND_PASS
+} sysrq_state;
+extern struct sysrq_ctls_struct sysrq_ctls;
#endif
static struct pm_dev *pm_kbd;
@@ -246,15 +259,76 @@
} else
rep = test_and_set_bit(keycode, key_down);
-#ifdef CONFIG_MAGIC_SYSRQ /* Handle the SysRq Hack */
- if (keycode == SYSRQ_KEY) {
- sysrq_pressed = !up_flag;
- goto out;
- } else if (sysrq_pressed) {
- if (!up_flag) {
- handle_sysrq(kbd_sysrq_xlate[keycode], kbd_pt_regs, kbd, tty);
- goto out;
+#ifdef CONFIG_MAGIC_SYSRQ /* Handle the SysRq Hack */
+ /*
+ Pressing magic + command key acts as a chorded command.
+ Pressing and releasing magic without a command key acts sticky,
+ using the next non-magic key as a command key
+ Pressing magic twice without a command key passes the magic key
+ through.
+ */
+
+ if (sysrq_ctls.enabled) {
+ if (keycode == sysrq_ctls.keycode) switch(sysrq_state) {
+ case UP_AND_CLEAR:
+ sysrq_state = up_flag ? UP_AND_CLEAR :
+ DOWN_AND_WAITING;
+ /* consume the key event */
+ goto out;
+
+ case DOWN_AND_WAITING:
+ if (up_flag) {
+ if (sysrq_ctls.sticky) {
+ sysrq_state = UP_AND_WAITING;
+ } else {
+ sysrq_state = UP_AND_CLEAR;
+ }
+ } else {
+ sysrq_state = DOWN_AND_WAITING;
+ }
+ /* consume the key event */
+ goto out;
+
+ case DOWN_AND_DONE:
+ sysrq_state = up_flag ? UP_AND_CLEAR :
+ DOWN_AND_DONE;
+ /* consume the key event */
+ goto out;
+
+ case DOWN_AND_PASS:
+ case UP_AND_WAITING:
+ sysrq_state = up_flag ? UP_AND_CLEAR :
+ DOWN_AND_PASS;
+ /* pass the key event through */
+ break;
+
+ } else switch(sysrq_state) {
+ case UP_AND_WAITING:
+ case DOWN_AND_WAITING:
+ case DOWN_AND_DONE:
+ if (!up_flag) {
+ handle_sysrq(kbd_sysrq_xlate[keycode],
+ kbd_pt_regs, kbd, tty);
+ }
+
+ if (sysrq_state == UP_AND_WAITING) {
+ sysrq_state = UP_AND_CLEAR;
+ } else {
+ sysrq_state = DOWN_AND_DONE;
+ }
+
+ /* consume the key event */
+ goto out;
+
+
+ case DOWN_AND_PASS:
+ case UP_AND_CLEAR:
+ /* pass the key event through */
+ break;
+
}
+ } else {
+ sysrq_state = UP_AND_CLEAR;
}
#endif
diff -ur linux-2.4.11-pre2/drivers/char/sysrq.c linux-2.4.11-pre2-stateful_sysrq/drivers/char/sysrq.c
--- linux-2.4.11-pre2/drivers/char/sysrq.c Mon Oct 1 23:13:36 2001
+++ linux-2.4.11-pre2-stateful_sysrq/drivers/char/sysrq.c Wed Oct 3 09:55:42 2001
@@ -32,12 +32,24 @@
#include <asm/ptrace.h>
+/* for the SYSRQ_KEY definition */
+#include <asm/keyboard.h>
+
extern void reset_vc(unsigned int);
extern struct list_head super_blocks;
/* Whether we react on sysrq keys or just ignore them */
-int sysrq_enabled = 1;
+struct sysrq_ctls_struct sysrq_ctls = {
+ /* Whether we react on sysrq keys or just ignore them */
+ enabled: 1,
+
+ /* The keycode for the magic key, referred to as sysrq */
+ keycode: SYSRQ_KEY,
+ /* is the sysrq key 'sticky'? */
+ sticky: 0,
+};
+
/* Machine specific power off function */
void (*sysrq_power_off)(void);
@@ -231,7 +243,7 @@
static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
emergency_sync_scheduled = EMERG_REMOUNT;
- wakeup_bdflush(0);
+ wakeup_bdflush();
}
static struct sysrq_key_op sysrq_mountro_op = {
handler: sysrq_handle_mountro,
@@ -433,7 +445,7 @@
void handle_sysrq(int key, struct pt_regs *pt_regs,
struct kbd_struct *kbd, struct tty_struct *tty) {
- if (!sysrq_enabled)
+ if (!sysrq_ctls.enabled)
return;
__sysrq_lock_table();
@@ -453,7 +465,7 @@
int orig_log_level;
int i, j;
- if (!sysrq_enabled)
+ if (!sysrq_ctls.enabled)
return;
orig_log_level = console_loglevel;
diff -ur linux-2.4.11-pre2/include/linux/sysctl.h linux-2.4.11-pre2-stateful_sysrq/include/linux/sysctl.h
--- linux-2.4.11-pre2/include/linux/sysctl.h Mon Oct 1 23:13:44 2001
+++ linux-2.4.11-pre2-stateful_sysrq/include/linux/sysctl.h Wed Oct 3 00:17:13 2001
@@ -106,7 +106,7 @@
KERN_MSGMAX=35, /* int: Maximum size of a messege */
KERN_MSGMNB=36, /* int: Maximum message queue size */
KERN_MSGPOOL=37, /* int: Maximum system message pool size */
- KERN_SYSRQ=38, /* int: Sysreq enable */
+ KERN_SYSRQ=38, /* struct: Sysreq enable, keycode, sticky */
KERN_MAX_THREADS=39, /* int: Maximum nr of threads in the system */
KERN_RANDOM=40, /* Random driver */
KERN_SHMALL=41, /* int: Maximum size of shared memory */
diff -ur linux-2.4.11-pre2/include/linux/sysrq.h linux-2.4.11-pre2-stateful_sysrq/include/linux/sysrq.h
--- linux-2.4.11-pre2/include/linux/sysrq.h Mon Oct 1 23:13:44 2001
+++ linux-2.4.11-pre2-stateful_sysrq/include/linux/sysrq.h Wed Oct 3 00:15:26 2001
@@ -26,6 +26,13 @@
#ifdef CONFIG_MAGIC_SYSRQ
+/* sysrq_ctls - controls aspects of the SYSRQ magic key hack*/
+struct sysrq_ctls_struct {
+ int enabled;
+ int keycode;
+ int sticky;
+};
+
/* Generic SysRq interface -- you may call it from any device driver, supplying
* ASCII code of the key, pointer to registers and kbd/tty structs (if they
* are available -- else NULL's).
diff -ur linux-2.4.11-pre2/kernel/sysctl.c linux-2.4.11-pre2-stateful_sysrq/kernel/sysctl.c
--- linux-2.4.11-pre2/kernel/sysctl.c Mon Oct 1 23:13:44 2001
+++ linux-2.4.11-pre2-stateful_sysrq/kernel/sysctl.c Wed Oct 3 00:18:43 2001
@@ -46,7 +46,7 @@
extern int sysctl_overcommit_memory;
extern int max_threads;
extern int nr_queued_signals, max_queued_signals;
-extern int sysrq_enabled;
+extern struct sysrq_ctls_struct sysrq_ctls;
extern int core_uses_pid;
extern int cad_pid;
@@ -233,7 +233,11 @@
0644, NULL, &proc_dointvec},
#endif
#ifdef CONFIG_MAGIC_SYSRQ
- {KERN_SYSRQ, "sysrq", &sysrq_enabled, sizeof (int),
+ {KERN_SYSRQ, "sysrq", &sysrq_ctls.enabled, sizeof (int),
+ 0644, NULL, &proc_dointvec},
+ {KERN_SYSRQ, "sysrq-key", &sysrq_ctls.keycode, sizeof (sysrq_ctls.keycode),
+ 0644, NULL, &proc_dointvec},
+ {KERN_SYSRQ, "sysrq-sticky", &sysrq_ctls.sticky, sizeof (sysrq_ctls.sticky),
0644, NULL, &proc_dointvec},
#endif
{KERN_CADPID, "cad_pid", &cad_pid, sizeof (int),
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2001-10-03 14:05 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2001-10-02 8:48 [PATCH] Stateful Magic Sysrq Key willy tarreau
2001-10-02 14:18 ` Crutcher Dunnavant
2001-10-03 14:05 ` [PATCH] Stateful Magic Sysrq Key + Sticky Tag Crutcher Dunnavant
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox