[patch 0/1] hvc_console: send magic sysrq key to terminal

[patch 0/1] hvc_console: send magic sysrq key to terminal

[Hendrik Brueckner]

Hello,

the patch allows to send the magic sysrq key to the terminal (if pressed twice),
so that it can be consumed by applications (e.g. ^0 is used by some editors...)


Ben, Paul, could you add the patch to your powerpc tree?

Thanks and regards, 
Hendrik

-- 
Hendrik Brueckner
D/3303 Linux on System z Development
eMail: brueckner@linux.vnet.ibm.com
IBM Deutschland Research & Development GmbH, Schoenaicher Str. 220, 71032 Boeblingen

IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martin Jetter
Geschaeftsfuehrung: Erich Baier
Sitz der Gesellschaft: Boeblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294

[patch 1/1] hvc_console: escape magic sysrq key

[Hendrik Brueckner]

From: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>

The ctrl-o (^O) is a common control key used by several applications like vim.

To allow users to send ^O to the terminal, this patch introduces a check
if ^O is pressed again if the sysrq_pressed variable is already set.
In this case, clear sysrq_pressed state and flip the ^O character to the tty.
(The old behavior has always set "sysrq_pressed" if ^0 has been entered, and it
has not flipped the ^O character to the tty.)

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
---
 drivers/char/hvc_console.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -642,8 +642,11 @@ int hvc_poll(struct hvc_struct *hp)
 				/* Handle the SysRq Hack */
 				/* XXX should support a sequence */
 				if (buf[i] == '\x0f') {	/* ^O */
-					sysrq_pressed = 1;
-					continue;
+					/* if ^0 is pressed again, reset
+					 * sysrq_pressed and flip ^0 char */
+					sysrq_pressed = (sysrq_pressed) ? 0 : 1;
+					if (sysrq_pressed)
+						continue;
 				} else if (sysrq_pressed) {
 					handle_sysrq(buf[i], tty);
 					sysrq_pressed = 0;

-- 
Hendrik Brueckner
D/3303 Linux on System z Development
eMail: brueckner@linux.vnet.ibm.com
IBM Deutschland Research & Development GmbH, Schoenaicher Str. 220, 71032 Boeblingen

IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martin Jetter
Geschaeftsfuehrung: Erich Baier
Sitz der Gesellschaft: Boeblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294

Re: [patch 1/1] hvc_console: escape magic sysrq key

[Andreas Schwab]

Hendrik Brueckner <brueckner@linux.vnet.ibm.com> writes:

> +					/* if ^0 is pressed again, reset
> +					 * sysrq_pressed and flip ^0 char */

The comment says ^0 twice when ^O is meant.

> +					sysrq_pressed = (sysrq_pressed) ? 0 : 1;

                                        sysrq_pressed = !sysrc_pressed;

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: [patch 1/1 v2] hvc_console: escape magic sysrq key

[Hendrik Brueckner]

Hello Andreas,

thanks for your comments.

On Tue, Dec 16, 2008 at 10:36:55AM +0100, Andreas Schwab wrote:
> > +					/* if ^0 is pressed again, reset
> > +					 * sysrq_pressed and flip ^0 char */
> The comment says ^0 twice when ^O is meant.
Correct. I have updated the comment.

> > +					sysrq_pressed = (sysrq_pressed) ? 0 : 1;
>                                         sysrq_pressed = !sysrc_pressed;
Ok, it might look better.


[PATCH v2] hvc_console: escape magic sysrq key

From: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>

The ctrl-o (^O) is a common control key used by several applications like vim.

To allow users to send ^O to the terminal, this patch introduces a check
if ^O is pressed again if the sysrq_pressed variable is already set.
In this case, clear sysrq_pressed state and flip the ^O character to the tty.
(The old behavior has always set "sysrq_pressed" if ^O has been entered, and it
has not flipped the ^O character to the tty.)

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
---
 drivers/char/hvc_console.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -642,8 +642,11 @@ int hvc_poll(struct hvc_struct *hp)
 				/* Handle the SysRq Hack */
 				/* XXX should support a sequence */
 				if (buf[i] == '\x0f') {	/* ^O */
-					sysrq_pressed = 1;
-					continue;
+					/* if ^O is pressed again, reset
+					 * sysrq_pressed and flip ^O char */
+					sysrq_pressed = !sysrq_pressed;
+					if (sysrq_pressed)
+						continue;
 				} else if (sysrq_pressed) {
 					handle_sysrq(buf[i], tty);
 					sysrq_pressed = 0;