Hi Mathieu,
On Fri, Mar 22, 2013 at 08:36:42AM -0600, mathieu.poirier@xxxxxxxxxx wrote:
> +
> +static void sysrq_detect_reset_sequence(struct sysrq_state *state,
> unsigned int code, int value)
> {
> if (!test_bit(code, state->reset_keybit)) {
> @@ -628,18 +640,27 @@ static bool sysrq_detect_reset_sequence(struct sysrq_state *state,
> if (value && state->reset_seq_cnt)
> state->reset_canceled = true;
> } else if (value == 0) {
> - /* key release */
> + /*
> + * Key release - all keys in the reset sequence need
> + * to be pressed and held for the reset timeout
> + * to hold.
> + */
> + del_timer(&state->keyreset_timeout);
> +
I believe you need to cancel the timer also when any other key is
pressed (the branch above). Can you please try the version below?
I also realized that even when timer expires right away (the delay
is 0) it is not executed immediately (contrary to what I said earlier)
so I reverted to doing explicit call to reset instead of always using
timer.
Thanks.
--
Dmitry
Input: sysrq - supplementing reset sequence with timeout functionality
From: Mathieu J. Poirier <mathieu.poirier@xxxxxxxxxx>
Some devices have too few buttons, which it makes it hard to have
a reset combo that won't trigger automatically. As such a
timeout functionality that requires the combination to be held for
a given amount of time before triggering is introduced.
If a key combo is recognized and held for a 'timeout' amount of time,
the system triggers a reset. If the timeout value is omitted the
driver simply ignores the functionality.
Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---
drivers/tty/sysrq.c | 26 ++++++++++++++++++++------
1 file changed, 20 insertions(+), 6 deletions(-)
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 3687f0c..f31f417 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -43,6 +43,7 @@
#include <linux/input.h>
#include <linux/uaccess.h>
#include <linux/moduleparam.h>
+#include <linux/jiffies.h>
#include <asm/ptrace.h>
#include <asm/irq_regs.h>
@@ -51,6 +52,9 @@
static int __read_mostly sysrq_enabled = SYSRQ_DEFAULT_ENABLE;
static bool __read_mostly sysrq_always_enabled;
+unsigned short platform_sysrq_reset_seq[] __weak = { KEY_RESERVED };
+int sysrq_reset_downtime_ms __weak;
+
static bool sysrq_on(void)
{
return sysrq_enabled || sysrq_always_enabled;
@@ -586,6 +590,7 @@ struct sysrq_state {
int reset_seq_len;
int reset_seq_cnt;
int reset_seq_version;
+ struct timer_list keyreset_timer;
};
#define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */
@@ -644,6 +649,11 @@ static bool sysrq_detect_reset_sequence(struct sysrq_state *state,
return false;
}
+static void sysrq_do_reset(unsigned long dummy)
+{
+ __handle_sysrq(sysrq_xlate[KEY_B], false);
+}
+
static void sysrq_reinject_alt_sysrq(struct work_struct *work)
{
struct sysrq_state *sysrq =
@@ -748,10 +758,13 @@ static bool sysrq_handle_keypress(struct sysrq_state *sysrq,
if (was_active)
schedule_work(&sysrq->reinject_work);
- if (sysrq_detect_reset_sequence(sysrq, code, value)) {
- /* Force emergency reboot */
- __handle_sysrq(sysrq_xlate[KEY_B], false);
- }
+ if (!sysrq_detect_reset_sequence(sysrq, code, value))
+ del_timer(&sysrq->keyreset_timer);
+ else if (sysrq_reset_downtime_ms)
+ mod_timer(&sysrq->keyreset_timer,
+ jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms));
+ else
+ sysrq_do_reset(0);
} else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) {
/*
@@ -812,6 +825,7 @@ static int sysrq_connect(struct input_handler *handler,
sysrq->handle.handler = handler;
sysrq->handle.name = "sysrq";
sysrq->handle.private = sysrq;
+ setup_timer(&sysrq->keyreset_timer, sysrq_do_reset, 0);
error = input_register_handle(&sysrq->handle);
if (error) {
@@ -841,6 +855,7 @@ static void sysrq_disconnect(struct input_handle *handle)
input_close_device(handle);
cancel_work_sync(&sysrq->reinject_work);
+ del_timer_sync(&sysrq->keyreset_timer);
input_unregister_handle(handle);
kfree(sysrq);
}
@@ -870,8 +885,6 @@ static struct input_handler sysrq_handler = {
static bool sysrq_handler_registered;
-unsigned short platform_sysrq_reset_seq[] __weak = { KEY_RESERVED };
-
static inline void sysrq_register_handler(void)
{
unsigned short key;
@@ -930,6 +943,7 @@ static struct kernel_param_ops param_ops_sysrq_reset_seq = {
module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq,
&sysrq_reset_seq_len, 0644);
+module_param_named(reset_downtime_ms, sysrq_reset_downtime_ms, int, 0644);
#else
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