There exist machines which don't have SysRq key at all, e.g. chromebooks.
This patch allows configuring an alternative key to act as SysRq. Devices
which declare KEY_SYSRQ in their 'keybit' bitmap continue using KEY_SYSRQ,
but other devices use the alternative SysRq key instead, by default F10.
Which key is actually used can be modified with sysrq's module parameter.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx>
---
drivers/tty/sysrq.c | 28 +++++++++++++++++++++++++---
1 file changed, 25 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 0dc3878794fd..e1d271c84746 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -604,6 +604,7 @@ EXPORT_SYMBOL(handle_sysrq);
#ifdef CONFIG_INPUT
static int sysrq_reset_downtime_ms;
+static unsigned short alternative_sysrq_key = KEY_F10;
/* Simple translation table for the SysRq keys */
static const unsigned char sysrq_xlate[KEY_CNT] =
@@ -621,6 +622,7 @@ struct sysrq_state {
unsigned long key_down[BITS_TO_LONGS(KEY_CNT)];
unsigned int alt;
unsigned int alt_use;
+ unsigned short sysrq_key;
bool active;
bool need_reinject;
bool reinjecting;
@@ -770,10 +772,10 @@ static void sysrq_reinject_alt_sysrq(struct work_struct *work)
/* Simulate press and release of Alt + SysRq */
input_inject_event(handle, EV_KEY, alt_code, 1);
- input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1);
+ input_inject_event(handle, EV_KEY, sysrq->sysrq_key, 1);
input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
- input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0);
+ input_inject_event(handle, EV_KEY, sysrq->sysrq_key, 0);
input_inject_event(handle, EV_KEY, alt_code, 0);
input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
@@ -805,6 +807,7 @@ static bool sysrq_handle_keypress(struct sysrq_state *sysrq,
}
break;
+key_sysrq:
case KEY_SYSRQ:
if (value == 1 && sysrq->alt != KEY_RESERVED) {
sysrq->active = true;
@@ -825,11 +828,15 @@ static bool sysrq_handle_keypress(struct sysrq_state *sysrq,
* triggering print screen function.
*/
if (sysrq->active)
- clear_bit(KEY_SYSRQ, sysrq->handle.dev->key);
+ clear_bit(sysrq->sysrq_key, sysrq->handle.dev->key);
break;
default:
+ /* handle non-default sysrq key */
+ if (code == sysrq->sysrq_key)
+ goto key_sysrq;
+
if (sysrq->active && value && value != 2) {
sysrq->need_reinject = false;
__handle_sysrq(sysrq_xlate[code], true);
@@ -924,6 +931,14 @@ static int sysrq_connect(struct input_handler *handler,
sysrq->handle.private = sysrq;
timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0);
+ if (test_bit(KEY_SYSRQ, dev->keybit)) {
+ sysrq->sysrq_key = KEY_SYSRQ;
+ pr_info("%s: using default sysrq key [%x]\n", dev->name, KEY_SYSRQ);
+ } else {
+ sysrq->sysrq_key = alternative_sysrq_key;
+ pr_info("%s: Using alternative sysrq key: [%x]\n", dev->name, sysrq->sysrq_key);
+ }
+
error = input_register_handle(&sysrq->handle);
if (error) {
pr_err("Failed to register input sysrq handler, error %d\n",
@@ -1032,6 +1047,13 @@ module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq,
module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644);
+module_param(alternative_sysrq_key, ushort, 0644);
+MODULE_PARM_DESC(alternative_sysrq_key,
+ "Alternative SysRq key for input devices that don't have SysRq key. F10 by default.\n"
+ "Example\n"
+ "Using F9 as SysRq:\n"
+ "sysrq.alternative_sysrq_key=0x43\n");
+
#else
static inline void sysrq_register_handler(void)
base-commit: 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162
--
2.17.1
