On 11/3/21 8:54 AM, Andrzej Pietrasiewicz wrote:
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>
---
I'd like to resurrect an old thread regarding supporting alternative SysRq
key for machines which don't have a physical SysRq key at all.
The old thread:
https://www.spinics.net/lists/linux-input/msg67982.html
I'm resending this patch, rebased onto v5.15.
Any (new) thoughts about it?
Hi,
Did you test it with this patch?
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 c911196ac893..6dd288e53ce9 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -634,6 +634,7 @@ 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] =
@@ -653,6 +654,7 @@ struct sysrq_state {
unsigned int alt_use;
unsigned int shift;
unsigned int shift_use;
+ unsigned short sys
That line appears to need an ending ';'.
Or maybe that line was truncated since 'sys' isn't used anywhere in this patch.
bool active;
bool need_reinject;
bool reinjecting;
@@ -802,10 +804,10 @@ 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);
@@ -845,6 +847,7 @@ static bool sysrq_handle_keypress(struct sysrq_state *sysrq,
sysrq->shift = code;
break;
+key_sysrq:
case KEY_SYSRQ:
if (value == 1 && sysrq->alt != KEY_RESERVED) {
sysrq->active = true;
@@ -867,11 +870,15 @@ 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) {
unsigned char c = sysrq_xlate[code];
@@ -970,6 +977,14 @@ 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",
@@ -1078,6 +1093,13 @@ 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)
--
~Randy
