[RFC] tty/sysrq: Add alternative SysRq key

[RFC] tty/sysrq: Add alternative SysRq key

[Andrzej Pietrasiewicz]

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@collabora.com>
---
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?


 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
 	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)
-- 
2.17.1

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Randy Dunlap]

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@collabora.com>
> ---
> 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

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Andrzej Pietrasiewicz]

Hi Randy,

W dniu 03.11.2021 o 17:19, Randy Dunlap pisze:
> 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@collabora.com>
>> ---
>> 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?


Thanks... I must have sent an incorrect version (with incomplete
conflict resolution).

Andrzej

> 
> 
>>
>>   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)
>>
> 
> 

[RFC] tty/sysrq: Add alternative SysRq key

[Andrzej Pietrasiewicz]

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@collabora.com>
---


A corrected version with completed conflict resolution.



 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..fb59745b23c9 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 sysrq_key;
 	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)
-- 
2.17.1

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Greg Kroah-Hartman]

On Thu, Nov 04, 2021 at 10:34:29AM +0100, 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@collabora.com>
> ---
> 
> 
> A corrected version with completed conflict resolution.
> 
> 
> 
>  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..fb59745b23c9 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 sysrq_key;
>  	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)
> -- 
> 2.17.1
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- This looks like a new version of a previously submitted patch, but you
  did not list below the --- line any changes from the previous version.
  Please read the section entitled "The canonical patch format" in the
  kernel file, Documentation/SubmittingPatches for what needs to be done
  here to properly describe this.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
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thanks,

greg k-h's patch email bot

Re: [RFC] tty/sysrq: Add alternative SysRq key

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 44923 bytes --]

Hi Andrzej,

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on linux/master]
[also build test ERROR on hid/for-next linus/master v5.15 next-20211103]
[cannot apply to tty/tty-testing]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Andrzej-Pietrasiewicz/tty-sysrq-Add-alternative-SysRq-key/20211103-235630
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2f111a6fd5b5297b4e92f53798ca086f7c7d33a4
config: um-x86_64_defconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/ed36496ef4a480d6bc468152578cfb49a500e2dd
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Andrzej-Pietrasiewicz/tty-sysrq-Add-alternative-SysRq-key/20211103-235630
        git checkout ed36496ef4a480d6bc468152578cfb49a500e2dd
        # save the attached .config to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/tty/sysrq.c:658:2: error: expected ':', ',', ';', '}' or '__attribute__' before 'bool'
     658 |  bool active;
         |  ^~~~
   drivers/tty/sysrq.c: In function 'sysrq_parse_reset_sequence':
>> drivers/tty/sysrq.c:682:7: error: 'struct sysrq_state' has no member named 'reset_seq_cnt'
     682 |  state->reset_seq_cnt = 0;
         |       ^~
>> drivers/tty/sysrq.c:690:23: error: 'struct sysrq_state' has no member named 'reset_keybit'
     690 |   __set_bit(key, state->reset_keybit);
         |                       ^~
>> drivers/tty/sysrq.c:691:8: error: 'struct sysrq_state' has no member named 'reset_seq_len'
     691 |   state->reset_seq_len++;
         |        ^~
   drivers/tty/sysrq.c:694:9: error: 'struct sysrq_state' has no member named 'reset_seq_cnt'
     694 |    state->reset_seq_cnt++;
         |         ^~
>> drivers/tty/sysrq.c:698:7: error: 'struct sysrq_state' has no member named 'reset_canceled'
     698 |  state->reset_canceled = state->reset_seq_cnt != 0;
         |       ^~
   drivers/tty/sysrq.c:698:31: error: 'struct sysrq_state' has no member named 'reset_seq_cnt'
     698 |  state->reset_canceled = state->reset_seq_cnt != 0;
         |                               ^~
>> drivers/tty/sysrq.c:700:7: error: 'struct sysrq_state' has no member named 'reset_seq_version'
     700 |  state->reset_seq_version = sysrq_reset_seq_version;
         |       ^~
   In file included from <command-line>:
   drivers/tty/sysrq.c: In function 'sysrq_do_reset':
>> include/linux/kernel.h:495:51: error: 'struct sysrq_state' has no member named 'keyreset_timer'
     495 |  BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
         |                                                   ^~
   include/linux/compiler_types.h:302:9: note: in definition of macro '__compiletime_assert'
     302 |   if (!(condition))     \
         |         ^~~~~~~~~
   include/linux/compiler_types.h:322:2: note: in expansion of macro '_compiletime_assert'
     322 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |  ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^~~~~~~~~~~~~~~~~~
   include/linux/kernel.h:495:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
     495 |  BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
         |  ^~~~~~~~~~~~~~~~
   include/linux/kernel.h:495:20: note: in expansion of macro '__same_type'
     495 |  BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
         |                    ^~~~~~~~~~~
   include/linux/timer.h:154:2: note: in expansion of macro 'container_of'
     154 |  container_of(callback_timer, typeof(*var), timer_fieldname)
         |  ^~~~~~~~~~~~
   drivers/tty/sysrq.c:705:30: note: in expansion of macro 'from_timer'
     705 |  struct sysrq_state *state = from_timer(state, t, keyreset_timer);
         |                              ^~~~~~~~~~
>> include/linux/compiler_types.h:140:35: error: 'struct sysrq_state' has no member named 'keyreset_timer'
     140 | #define __compiler_offsetof(a, b) __builtin_offsetof(a, b)
         |                                   ^~~~~~~~~~~~~~~~~~
   include/linux/stddef.h:17:32: note: in expansion of macro '__compiler_offsetof'
      17 | #define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE, MEMBER)
         |                                ^~~~~~~~~~~~~~~~~~~
   include/linux/kernel.h:498:21: note: in expansion of macro 'offsetof'
     498 |  ((type *)(__mptr - offsetof(type, member))); })
         |                     ^~~~~~~~
   include/linux/timer.h:154:2: note: in expansion of macro 'container_of'
     154 |  container_of(callback_timer, typeof(*var), timer_fieldname)
         |  ^~~~~~~~~~~~
   drivers/tty/sysrq.c:705:30: note: in expansion of macro 'from_timer'
     705 |  struct sysrq_state *state = from_timer(state, t, keyreset_timer);
         |                              ^~~~~~~~~~
>> drivers/tty/sysrq.c:707:7: error: 'struct sysrq_state' has no member named 'reset_requested'
     707 |  state->reset_requested = true;
         |       ^~
   drivers/tty/sysrq.c: In function 'sysrq_handle_reset_request':
   drivers/tty/sysrq.c:714:11: error: 'struct sysrq_state' has no member named 'reset_requested'
     714 |  if (state->reset_requested)
         |           ^~
>> drivers/tty/sysrq.c:718:19: error: 'struct sysrq_state' has no member named 'keyreset_timer'
     718 |   mod_timer(&state->keyreset_timer,
         |                   ^~
   drivers/tty/sysrq.c:721:24: error: 'struct sysrq_state' has no member named 'keyreset_timer'
     721 |   sysrq_do_reset(&state->keyreset_timer);
         |                        ^~
   drivers/tty/sysrq.c: In function 'sysrq_detect_reset_sequence':
   drivers/tty/sysrq.c:727:27: error: 'struct sysrq_state' has no member named 'reset_keybit'
     727 |  if (!test_bit(code, state->reset_keybit)) {
         |                           ^~
   drivers/tty/sysrq.c:734:21: error: 'struct sysrq_state' has no member named 'reset_seq_cnt'
     734 |   if (value && state->reset_seq_cnt) {
         |                     ^~
   drivers/tty/sysrq.c:735:9: error: 'struct sysrq_state' has no member named 'reset_canceled'
     735 |    state->reset_canceled = true;
         |         ^~
   drivers/tty/sysrq.c:736:20: error: 'struct sysrq_state' has no member named 'keyreset_timer'
     736 |    del_timer(&state->keyreset_timer);
         |                    ^~
   drivers/tty/sysrq.c:744:19: error: 'struct sysrq_state' has no member named 'keyreset_timer'
     744 |   del_timer(&state->keyreset_timer);
         |                   ^~
   drivers/tty/sysrq.c:746:14: error: 'struct sysrq_state' has no member named 'reset_seq_cnt'
     746 |   if (--state->reset_seq_cnt == 0)
         |              ^~
   drivers/tty/sysrq.c:747:9: error: 'struct sysrq_state' has no member named 'reset_canceled'
     747 |    state->reset_canceled = false;
         |         ^~
   drivers/tty/sysrq.c:750:14: error: 'struct sysrq_state' has no member named 'reset_seq_cnt'
     750 |   if (++state->reset_seq_cnt == state->reset_seq_len &&
         |              ^~
   drivers/tty/sysrq.c:750:38: error: 'struct sysrq_state' has no member named 'reset_seq_len'
     750 |   if (++state->reset_seq_cnt == state->reset_seq_len &&
         |                                      ^~
   drivers/tty/sysrq.c:751:13: error: 'struct sysrq_state' has no member named 'reset_canceled'
     751 |       !state->reset_canceled) {
         |             ^~
   drivers/tty/sysrq.c: In function 'sysrq_reinject_alt_sysrq':
>> drivers/tty/sysrq.c:800:11: error: 'struct sysrq_state' has no member named 'need_reinject'
     800 |  if (sysrq->need_reinject) {
         |           ^~
>> drivers/tty/sysrq.c:802:10: error: 'struct sysrq_state' has no member named 'reinjecting'; did you mean 'reinject_work'?
     802 |   sysrq->reinjecting = true;
         |          ^~~~~~~~~~~
         |          reinject_work
>> drivers/tty/sysrq.c:807:43: error: 'struct sysrq_state' has no member named 'sysrq_key'
     807 |   input_inject_event(handle, EV_KEY, sysrq->sysrq_key, 1);
         |                                           ^~
   drivers/tty/sysrq.c:810:43: error: 'struct sysrq_state' has no member named 'sysrq_key'
     810 |   input_inject_event(handle, EV_KEY, sysrq->sysrq_key, 0);
         |                                           ^~
   drivers/tty/sysrq.c:815:10: error: 'struct sysrq_state' has no member named 'reinjecting'; did you mean 'reinject_work'?
     815 |   sysrq->reinjecting = false;
         |          ^~~~~~~~~~~
         |          reinject_work
   drivers/tty/sysrq.c: In function 'sysrq_handle_keypress':
>> drivers/tty/sysrq.c:822:25: error: 'struct sysrq_state' has no member named 'active'
     822 |  bool was_active = sysrq->active;
         |                         ^~
   drivers/tty/sysrq.c:831:13: error: 'struct sysrq_state' has no member named 'active'
     831 |    if (sysrq->active && code == sysrq->alt_use)
         |             ^~
   drivers/tty/sysrq.c:832:10: error: 'struct sysrq_state' has no member named 'active'
     832 |     sysrq->active = false;
         |          ^~
   drivers/tty/sysrq.c:838:9: error: 'struct sysrq_state' has no member named 'need_reinject'
     838 |    sysrq->need_reinject = false;
         |         ^~
   drivers/tty/sysrq.c:853:9: error: 'struct sysrq_state' has no member named 'active'
     853 |    sysrq->active = true;
         |         ^~
   drivers/tty/sysrq.c:861:9: error: 'struct sysrq_state' has no member named 'need_reinject'
     861 |    sysrq->need_reinject = true;
         |         ^~
   drivers/tty/sysrq.c:872:12: error: 'struct sysrq_state' has no member named 'active'
     872 |   if (sysrq->active)
         |            ^~
   drivers/tty/sysrq.c:873:19: error: 'struct sysrq_state' has no member named 'sysrq_key'
     873 |    clear_bit(sysrq->sysrq_key, sysrq->handle.dev->key);
         |                   ^~
   drivers/tty/sysrq.c:879:20: error: 'struct sysrq_state' has no member named 'sysrq_key'
     879 |   if (code == sysrq->sysrq_key)
         |                    ^~
   drivers/tty/sysrq.c:882:12: error: 'struct sysrq_state' has no member named 'active'
     882 |   if (sysrq->active && value && value != 2) {
         |            ^~
   drivers/tty/sysrq.c:885:9: error: 'struct sysrq_state' has no member named 'need_reinject'
     885 |    sysrq->need_reinject = false;
         |         ^~
   drivers/tty/sysrq.c:893:18: error: 'struct sysrq_state' has no member named 'active'
     893 |  suppress = sysrq->active;
         |                  ^~
   drivers/tty/sysrq.c:895:12: error: 'struct sysrq_state' has no member named 'active'
     895 |  if (!sysrq->active) {
         |            ^~
   drivers/tty/sysrq.c:900:12: error: 'struct sysrq_state' has no member named 'reset_seq_version'
     900 |   if (sysrq->reset_seq_version != sysrq_reset_seq_version)
         |            ^~
   drivers/tty/sysrq.c: In function 'sysrq_filter':
   drivers/tty/sysrq.c:940:13: error: 'struct sysrq_state' has no member named 'reinjecting'; did you mean 'reinject_work'?
     940 |  if (sysrq->reinjecting)
         |             ^~~~~~~~~~~
         |             reinject_work
   drivers/tty/sysrq.c:954:19: error: 'struct sysrq_state' has no member named 'active'
     954 |   suppress = sysrq->active;
         |                   ^~
   In file included from include/linux/workqueue.h:9,
                    from include/linux/rhashtable-types.h:15,
                    from include/linux/ipc.h:7,
                    from include/uapi/linux/sem.h:5,
                    from include/linux/sem.h:5,
                    from include/linux/sched.h:15,
                    from include/linux/sched/signal.h:7,
                    from drivers/tty/sysrq.c:18:
   drivers/tty/sysrq.c: In function 'sysrq_connect':
   drivers/tty/sysrq.c:978:20: error: 'struct sysrq_state' has no member named 'keyreset_timer'
     978 |  timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0);
         |                    ^~
   include/linux/timer.h:126:18: note: in definition of macro '__init_timer'
     126 |  init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
         |                  ^~~~~~
   drivers/tty/sysrq.c:978:2: note: in expansion of macro 'timer_setup'
     978 |  timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0);
         |  ^~~~~~~~~~~
   drivers/tty/sysrq.c:981:8: error: 'struct sysrq_state' has no member named 'sysrq_key'
     981 |   sysrq->sysrq_key = KEY_SYSRQ;
         |        ^~
   drivers/tty/sysrq.c:984:8: error: 'struct sysrq_state' has no member named 'sysrq_key'
     984 |   sysrq->sysrq_key = alternative_sysrq_key;
         |        ^~
   In file included from include/linux/kernel.h:19,
                    from include/linux/list.h:9,
                    from include/linux/rculist.h:10,
                    from include/linux/sched/signal.h:5,
                    from drivers/tty/sysrq.c:18:
   drivers/tty/sysrq.c:985:70: error: 'struct sysrq_state' has no member named 'sysrq_key'
     985 |   pr_info("%s: Using alternative sysrq key: [%x]\n", dev->name, sysrq->sysrq_key);
         |                                                                      ^~
   include/linux/printk.h:418:19: note: in definition of macro 'printk_index_wrap'
     418 |   _p_func(_fmt, ##__VA_ARGS__);    \
         |                   ^~~~~~~~~~~
   include/linux/printk.h:519:2: note: in expansion of macro 'printk'
     519 |  printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
         |  ^~~~~~
   drivers/tty/sysrq.c:985:3: note: in expansion of macro 'pr_info'
     985 |   pr_info("%s: Using alternative sysrq key: [%x]\n", dev->name, sysrq->sysrq_key);
         |   ^~~~~~~
   In file included from include/linux/workqueue.h:9,
                    from include/linux/rhashtable-types.h:15,
                    from include/linux/ipc.h:7,
                    from include/uapi/linux/sem.h:5,
                    from include/linux/sem.h:5,
                    from include/linux/sched.h:15,
                    from include/linux/sched/signal.h:7,
                    from drivers/tty/sysrq.c:18:
   drivers/tty/sysrq.c: In function 'sysrq_disconnect':
   drivers/tty/sysrq.c:1016:23: error: 'struct sysrq_state' has no member named 'keyreset_timer'


vim +658 drivers/tty/sysrq.c

97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  638  
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  639  /* Simple translation table for the SysRq keys */
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  640  static const unsigned char sysrq_xlate[KEY_CNT] =
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  641  	"\000\0331234567890-=\177\t"                    /* 0x00 - 0x0f */
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  642  	"qwertyuiop[]\r\000as"                          /* 0x10 - 0x1f */
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  643  	"dfghjkl;'`\000\\zxcv"                          /* 0x20 - 0x2f */
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  644  	"bnm,./\000*\000 \000\201\202\203\204\205"      /* 0x30 - 0x3f */
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  645  	"\206\207\210\211\212\000\000789-456+1"         /* 0x40 - 0x4f */
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  646  	"230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  647  	"\r\000/";                                      /* 0x60 - 0x6f */
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  648  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  649  struct sysrq_state {
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  650  	struct input_handle handle;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  651  	struct work_struct reinject_work;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  652  	unsigned long key_down[BITS_TO_LONGS(KEY_CNT)];
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  653  	unsigned int alt;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  654  	unsigned int alt_use;
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  655  	unsigned int shift;
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  656  	unsigned int shift_use;
ed36496ef4a480 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2021-11-03  657  	unsigned short sys
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15 @658  	bool active;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  659  	bool need_reinject;
7ab7b5adfb9239 drivers/char/sysrq.c Dmitry Torokhov       2011-02-02  660  	bool reinjecting;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  661  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  662  	/* reset sequence handling */
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  663  	bool reset_canceled;
3d289517dfd48f drivers/tty/sysrq.c  Mathieu J. Poirier    2013-06-05  664  	bool reset_requested;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  665  	unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)];
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  666  	int reset_seq_len;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  667  	int reset_seq_cnt;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  668  	int reset_seq_version;
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  669  	struct timer_list keyreset_timer;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  670  };
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  671  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  672  #define SYSRQ_KEY_RESET_MAX	20 /* Should be plenty */
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  673  static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX];
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  674  static unsigned int sysrq_reset_seq_len;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  675  static unsigned int sysrq_reset_seq_version = 1;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  676  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  677  static void sysrq_parse_reset_sequence(struct sysrq_state *state)
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  678  {
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  679  	int i;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  680  	unsigned short key;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  681  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06 @682  	state->reset_seq_cnt = 0;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  683  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  684  	for (i = 0; i < sysrq_reset_seq_len; i++) {
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  685  		key = sysrq_reset_seq[i];
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  686  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  687  		if (key == KEY_RESERVED || key > KEY_MAX)
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  688  			break;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  689  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06 @690  		__set_bit(key, state->reset_keybit);
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06 @691  		state->reset_seq_len++;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  692  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  693  		if (test_bit(key, state->key_down))
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  694  			state->reset_seq_cnt++;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  695  	}
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  696  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  697  	/* Disable reset until old keys are not released */
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06 @698  	state->reset_canceled = state->reset_seq_cnt != 0;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  699  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06 @700  	state->reset_seq_version = sysrq_reset_seq_version;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  701  }
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  702  
8c318fa93dfcd1 drivers/tty/sysrq.c  Kees Cook             2017-10-16  703  static void sysrq_do_reset(struct timer_list *t)
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  704  {
8c318fa93dfcd1 drivers/tty/sysrq.c  Kees Cook             2017-10-16  705  	struct sysrq_state *state = from_timer(state, t, keyreset_timer);
3d289517dfd48f drivers/tty/sysrq.c  Mathieu J. Poirier    2013-06-05  706  
3d289517dfd48f drivers/tty/sysrq.c  Mathieu J. Poirier    2013-06-05 @707  	state->reset_requested = true;
3d289517dfd48f drivers/tty/sysrq.c  Mathieu J. Poirier    2013-06-05  708  
8fefbc6d4b2660 drivers/tty/sysrq.c  Mark Tomlinson        2018-11-27  709  	orderly_reboot();
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  710  }
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  711  
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  712  static void sysrq_handle_reset_request(struct sysrq_state *state)
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  713  {
3d289517dfd48f drivers/tty/sysrq.c  Mathieu J. Poirier    2013-06-05  714  	if (state->reset_requested)
3d289517dfd48f drivers/tty/sysrq.c  Mathieu J. Poirier    2013-06-05  715  		__handle_sysrq(sysrq_xlate[KEY_B], false);
3d289517dfd48f drivers/tty/sysrq.c  Mathieu J. Poirier    2013-06-05  716  
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  717  	if (sysrq_reset_downtime_ms)
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01 @718  		mod_timer(&state->keyreset_timer,
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  719  			jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms));
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  720  	else
8c318fa93dfcd1 drivers/tty/sysrq.c  Kees Cook             2017-10-16  721  		sysrq_do_reset(&state->keyreset_timer);
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  722  }
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  723  
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  724  static void sysrq_detect_reset_sequence(struct sysrq_state *state,
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  725  					unsigned int code, int value)
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  726  {
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  727  	if (!test_bit(code, state->reset_keybit)) {
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  728  		/*
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  729  		 * Pressing any key _not_ in reset sequence cancels
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  730  		 * the reset sequence.  Also cancelling the timer in
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  731  		 * case additional keys were pressed after a reset
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  732  		 * has been requested.
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  733  		 */
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  734  		if (value && state->reset_seq_cnt) {
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  735  			state->reset_canceled = true;
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  736  			del_timer(&state->keyreset_timer);
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  737  		}
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  738  	} else if (value == 0) {
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  739  		/*
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  740  		 * Key release - all keys in the reset sequence need
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  741  		 * to be pressed and held for the reset timeout
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  742  		 * to hold.
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  743  		 */
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  744  		del_timer(&state->keyreset_timer);
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  745  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  746  		if (--state->reset_seq_cnt == 0)
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  747  			state->reset_canceled = false;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  748  	} else if (value == 1) {
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  749  		/* key press, not autorepeat */
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  750  		if (++state->reset_seq_cnt == state->reset_seq_len &&
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  751  		    !state->reset_canceled) {
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  752  			sysrq_handle_reset_request(state);
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  753  		}
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  754  	}
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  755  }
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  756  
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  757  #ifdef CONFIG_OF
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  758  static void sysrq_of_get_keyreset_config(void)
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  759  {
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  760  	u32 key;
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  761  	struct device_node *np;
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  762  	struct property *prop;
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  763  	const __be32 *p;
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  764  
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  765  	np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq");
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  766  	if (!np) {
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  767  		pr_debug("No sysrq node found");
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  768  		return;
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  769  	}
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  770  
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  771  	/* Reset in case a __weak definition was present */
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  772  	sysrq_reset_seq_len = 0;
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  773  
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  774  	of_property_for_each_u32(np, "keyset", prop, p, key) {
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  775  		if (key == KEY_RESERVED || key > KEY_MAX ||
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  776  		    sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX)
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  777  			break;
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  778  
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  779  		sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key;
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  780  	}
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  781  
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  782  	/* Get reset timeout if any. */
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  783  	of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms);
279070b96a5a08 drivers/tty/sysrq.c  Yangtao Li            2018-11-21  784  
279070b96a5a08 drivers/tty/sysrq.c  Yangtao Li            2018-11-21  785  	of_node_put(np);
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  786  }
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  787  #else
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  788  static void sysrq_of_get_keyreset_config(void)
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  789  {
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  790  }
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  791  #endif
4c076eb0cfd9fa drivers/tty/sysrq.c  Mathieu J. Poirier    2013-08-03  792  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  793  static void sysrq_reinject_alt_sysrq(struct work_struct *work)
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  794  {
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  795  	struct sysrq_state *sysrq =
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  796  			container_of(work, struct sysrq_state, reinject_work);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  797  	struct input_handle *handle = &sysrq->handle;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  798  	unsigned int alt_code = sysrq->alt_use;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  799  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15 @800  	if (sysrq->need_reinject) {
7ab7b5adfb9239 drivers/char/sysrq.c Dmitry Torokhov       2011-02-02  801  		/* we do not want the assignment to be reordered */
7ab7b5adfb9239 drivers/char/sysrq.c Dmitry Torokhov       2011-02-02 @802  		sysrq->reinjecting = true;
7ab7b5adfb9239 drivers/char/sysrq.c Dmitry Torokhov       2011-02-02  803  		mb();
7ab7b5adfb9239 drivers/char/sysrq.c Dmitry Torokhov       2011-02-02  804  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  805  		/* Simulate press and release of Alt + SysRq */
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  806  		input_inject_event(handle, EV_KEY, alt_code, 1);
ed36496ef4a480 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2021-11-03 @807  		input_inject_event(handle, EV_KEY, sysrq->sysrq_key, 1);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  808  		input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  809  
ed36496ef4a480 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2021-11-03  810  		input_inject_event(handle, EV_KEY, sysrq->sysrq_key, 0);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  811  		input_inject_event(handle, EV_KEY, alt_code, 0);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  812  		input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
7ab7b5adfb9239 drivers/char/sysrq.c Dmitry Torokhov       2011-02-02  813  
7ab7b5adfb9239 drivers/char/sysrq.c Dmitry Torokhov       2011-02-02  814  		mb();
7ab7b5adfb9239 drivers/char/sysrq.c Dmitry Torokhov       2011-02-02  815  		sysrq->reinjecting = false;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  816  	}
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  817  }
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  818  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  819  static bool sysrq_handle_keypress(struct sysrq_state *sysrq,
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  820  				  unsigned int code, int value)
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  821  {
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15 @822  	bool was_active = sysrq->active;
1966cb225c6f90 drivers/char/sysrq.c Dmitry Torokhov       2010-09-29  823  	bool suppress;
1966cb225c6f90 drivers/char/sysrq.c Dmitry Torokhov       2010-09-29  824  
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  825  	switch (code) {
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  826  
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  827  	case KEY_LEFTALT:
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  828  	case KEY_RIGHTALT:
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  829  		if (!value) {
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  830  			/* One of ALTs is being released */
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  831  			if (sysrq->active && code == sysrq->alt_use)
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  832  				sysrq->active = false;
f5dec51172b81d drivers/char/sysrq.c Dmitry Torokhov       2010-06-09  833  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  834  			sysrq->alt = KEY_RESERVED;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  835  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  836  		} else if (value != 2) {
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  837  			sysrq->alt = code;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  838  			sysrq->need_reinject = false;
f5dec51172b81d drivers/char/sysrq.c Dmitry Torokhov       2010-06-09  839  		}
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  840  		break;
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  841  
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  842  	case KEY_LEFTSHIFT:
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  843  	case KEY_RIGHTSHIFT:
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  844  		if (!value)
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  845  			sysrq->shift = KEY_RESERVED;
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  846  		else if (value != 2)
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  847  			sysrq->shift = code;
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  848  		break;
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  849  
ed36496ef4a480 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2021-11-03  850  key_sysrq:
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  851  	case KEY_SYSRQ:
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  852  		if (value == 1 && sysrq->alt != KEY_RESERVED) {
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  853  			sysrq->active = true;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  854  			sysrq->alt_use = sysrq->alt;
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  855  			/* either RESERVED (for released) or actual code */
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  856  			sysrq->shift_use = sysrq->shift;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  857  			/*
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  858  			 * If nothing else will be pressed we'll need
7ab7b5adfb9239 drivers/char/sysrq.c Dmitry Torokhov       2011-02-02  859  			 * to re-inject Alt-SysRq keysroke.
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  860  			 */
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  861  			sysrq->need_reinject = true;
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  862  		}
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  863  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  864  		/*
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  865  		 * Pretend that sysrq was never pressed at all. This
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  866  		 * is needed to properly handle KGDB which will try
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  867  		 * to release all keys after exiting debugger. If we
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  868  		 * do not clear key bit it KGDB will end up sending
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  869  		 * release events for Alt and SysRq, potentially
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  870  		 * triggering print screen function.
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  871  		 */
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  872  		if (sysrq->active)
ed36496ef4a480 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2021-11-03  873  			clear_bit(sysrq->sysrq_key, sysrq->handle.dev->key);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  874  
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  875  		break;
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  876  
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  877  	default:
ed36496ef4a480 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2021-11-03  878  		/* handle non-default sysrq key */
ed36496ef4a480 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2021-11-03  879  		if (code == sysrq->sysrq_key)
ed36496ef4a480 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2021-11-03  880  			goto key_sysrq;
ed36496ef4a480 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2021-11-03  881  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  882  		if (sysrq->active && value && value != 2) {
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  883  			unsigned char c = sysrq_xlate[code];
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  884  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  885  			sysrq->need_reinject = false;
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  886  			if (sysrq->shift_use != KEY_RESERVED)
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  887  				c = toupper(c);
a27eb0cb4b2104 drivers/tty/sysrq.c  Andrzej Pietrasiewicz 2020-08-18  888  			__handle_sysrq(c, true);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  889  		}
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  890  		break;
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  891  	}
97f5f0cd8cd0a0 drivers/char/sysrq.c Dmitry Torokhov       2010-03-21  892  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  893  	suppress = sysrq->active;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  894  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  895  	if (!sysrq->active) {
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  896  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  897  		/*
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  898  		 * See if reset sequence has changed since the last time.
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  899  		 */
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  900  		if (sysrq->reset_seq_version != sysrq_reset_seq_version)
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  901  			sysrq_parse_reset_sequence(sysrq);
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  902  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  903  		/*
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  904  		 * If we are not suppressing key presses keep track of
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  905  		 * keyboard state so we can release keys that have been
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  906  		 * pressed before entering SysRq mode.
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  907  		 */
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  908  		if (value)
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  909  			set_bit(code, sysrq->key_down);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  910  		else
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  911  			clear_bit(code, sysrq->key_down);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  912  
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  913  		if (was_active)
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  914  			schedule_work(&sysrq->reinject_work);
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  915  
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  916  		/* Check for reset sequence */
3903078677a8dc drivers/tty/sysrq.c  Mathieu J. Poirier    2013-04-01  917  		sysrq_detect_reset_sequence(sysrq, code, value);
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  918  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  919  	} else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) {
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  920  		/*
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  921  		 * Pass on release events for keys that was pressed before
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  922  		 * entering SysRq mode.
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  923  		 */
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  924  		suppress = false;
fcb7193096969c drivers/char/sysrq.c Dmitry Torokhov       2010-11-15  925  	}
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  926  
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  927  	return suppress;
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  928  }
154b7a489a5b1d drivers/tty/sysrq.c  Mathieu Poirier       2013-01-06  929  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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Re: [RFC] tty/sysrq: Add alternative SysRq key

[Pavel Machek]

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Hi!

> 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.

Is F10 sensible default? Would it make sense to use something like
alt-shift-esc so that this can be enabled by default?

Best regards,
								Pavel
-- 
http://www.livejournal.com/~pavelmachek

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Re: [RFC] tty/sysrq: Add alternative SysRq key

[Andrzej Pietrasiewicz]

Hi Pavel,

W dniu 04.11.2021 o 13:01, Pavel Machek pisze:
> Hi!
> 
>> 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.
> 
> Is F10 sensible default? Would it make sense to use something like
> alt-shift-esc so that this can be enabled by default?

Why "alt-shift-esc" could be enabled by default? Do you mean to enable it for
all systems regardless of whether they declare or don't declare KEY_SYSRQ
in their 'keybit' bitmap?

Andrzej

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Maciej W. Rozycki]

On Thu, 4 Nov 2021, Andrzej Pietrasiewicz wrote:

> > Is F10 sensible default? Would it make sense to use something like
> > alt-shift-esc so that this can be enabled by default?
> 
> Why "alt-shift-esc" could be enabled by default? Do you mean to enable it for
> all systems regardless of whether they declare or don't declare KEY_SYSRQ
> in their 'keybit' bitmap?

 FWIW from my perspective it'll work better as a replacement rather than 
additional key combination.

 The reason for this is with their more recent laptops Lenovo in their 
infinite wisdom have placed the <PrintScreen> key (which in a traditional 
PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their 
keyboards between the right <Alt> and <Ctrl> keys.  With thumbs not being 
as accurate as other fingers (and the overall misdesign of the keyboard 
and touchpad interface) you can imagine how often I have inadvertently hit 
<SysRq> combined with a letter key, wreaking havoc to my system (and of 
course I want to keep the key enabled for times when I do need it).

 Also Documentation/admin-guide/sysrq.rst mentions that you can set an 
alternative keycode sequence for KEY_SYSRQ with `setkeycodes <sequence> 
99' already, but I find this pretty limiting as this only works for single 
keypresses rather than combinations of keys, because <sequence> actually 
refers to a single scancode (possibly 0xe0-prefixed).

  Maciej

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Maciej W. Rozycki]

On Thu, 4 Nov 2021, Maciej W. Rozycki wrote:

>  The reason for this is with their more recent laptops Lenovo in their 
> infinite wisdom have placed the <PrintScreen> key (which in a traditional 
> PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their 
> keyboards between the right <Alt> and <Ctrl> keys.  With thumbs not being 
> as accurate as other fingers (and the overall misdesign of the keyboard 
> and touchpad interface) you can imagine how often I have inadvertently hit 
> <SysRq> combined with a letter key, wreaking havoc to my system (and of 
> course I want to keep the key enabled for times when I do need it).

 On second thoughts this can be disabled with `setkeycodes 54 0' once we 
do have an alternative combination available.

  Maciej

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Andrzej Pietrasiewicz]

Hi Maciej,

W dniu 04.11.2021 o 14:13, Maciej W. Rozycki pisze:
> On Thu, 4 Nov 2021, Maciej W. Rozycki wrote:
> 
>>   The reason for this is with their more recent laptops Lenovo in their
>> infinite wisdom have placed the <PrintScreen> key (which in a traditional
>> PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their
>> keyboards between the right <Alt> and <Ctrl> keys.  With thumbs not being
>> as accurate as other fingers (and the overall misdesign of the keyboard
>> and touchpad interface) you can imagine how often I have inadvertently hit
>> <SysRq> combined with a letter key, wreaking havoc to my system (and of
>> course I want to keep the key enabled for times when I do need it).
> 
>   On second thoughts this can be disabled with `setkeycodes 54 0' once we
> do have an alternative combination available.
> 

Doesn't `setkeycodes` affect only one keyboard? What if there are more
keyboards connected to a machine?

 From drivers/tty/vt/keyboard.c:

/*
  * Translation of scancodes to keycodes. We set them on only the first
  * keyboard in the list that accepts the scancode and keycode.
  * Explanation for not choosing the first attached keyboard anymore:
  *  USB keyboards for example have two event devices: one for all "normal"
  *  keys and one for extra function keys (like "volume up", "make coffee",
  *  etc.). So this means that scancodes for the extra function keys won't
  *  be valid for the first event device, but will be for the second.
  */

Regards,

Andrzej

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Andrzej Pietrasiewicz]

Hi,

W dniu 04.11.2021 o 15:17, Andrzej Pietrasiewicz pisze:
> Hi Maciej,
> 
> W dniu 04.11.2021 o 14:13, Maciej W. Rozycki pisze:
>> On Thu, 4 Nov 2021, Maciej W. Rozycki wrote:
>>
>>>   The reason for this is with their more recent laptops Lenovo in their
>>> infinite wisdom have placed the <PrintScreen> key (which in a traditional
>>> PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their
>>> keyboards between the right <Alt> and <Ctrl> keys.  With thumbs not being
>>> as accurate as other fingers (and the overall misdesign of the keyboard
>>> and touchpad interface) you can imagine how often I have inadvertently hit
>>> <SysRq> combined with a letter key, wreaking havoc to my system (and of
>>> course I want to keep the key enabled for times when I do need it).
>>
>>   On second thoughts this can be disabled with `setkeycodes 54 0' once we
>> do have an alternative combination available.
>>
> 
> Doesn't `setkeycodes` affect only one keyboard? What if there are more
> keyboards connected to a machine?
> 
>  From drivers/tty/vt/keyboard.c:
> 
> /*
>   * Translation of scancodes to keycodes. We set them on only the first
>   * keyboard in the list that accepts the scancode and keycode.
>   * Explanation for not choosing the first attached keyboard anymore:
>   *  USB keyboards for example have two event devices: one for all "normal"
>   *  keys and one for extra function keys (like "volume up", "make coffee",
>   *  etc.). So this means that scancodes for the extra function keys won't
>   *  be valid for the first event device, but will be for the second.
>   */
> 

My second thoughts: if we run `setkeycodes` to map, say, F10 as SysRq,
don't we lose F10?

Andrzej

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Greg Kroah-Hartman]

On Fri, Nov 05, 2021 at 02:01:23PM +0100, Andrzej Pietrasiewicz wrote:
> Hi,
> 
> W dniu 04.11.2021 o 15:17, Andrzej Pietrasiewicz pisze:
> > Hi Maciej,
> > 
> > W dniu 04.11.2021 o 14:13, Maciej W. Rozycki pisze:
> > > On Thu, 4 Nov 2021, Maciej W. Rozycki wrote:
> > > 
> > > >   The reason for this is with their more recent laptops Lenovo in their
> > > > infinite wisdom have placed the <PrintScreen> key (which in a traditional
> > > > PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their
> > > > keyboards between the right <Alt> and <Ctrl> keys.  With thumbs not being
> > > > as accurate as other fingers (and the overall misdesign of the keyboard
> > > > and touchpad interface) you can imagine how often I have inadvertently hit
> > > > <SysRq> combined with a letter key, wreaking havoc to my system (and of
> > > > course I want to keep the key enabled for times when I do need it).
> > > 
> > >   On second thoughts this can be disabled with `setkeycodes 54 0' once we
> > > do have an alternative combination available.
> > > 
> > 
> > Doesn't `setkeycodes` affect only one keyboard? What if there are more
> > keyboards connected to a machine?
> > 
> >  From drivers/tty/vt/keyboard.c:
> > 
> > /*
> >   * Translation of scancodes to keycodes. We set them on only the first
> >   * keyboard in the list that accepts the scancode and keycode.
> >   * Explanation for not choosing the first attached keyboard anymore:
> >   *  USB keyboards for example have two event devices: one for all "normal"
> >   *  keys and one for extra function keys (like "volume up", "make coffee",
> >   *  etc.). So this means that scancodes for the extra function keys won't
> >   *  be valid for the first event device, but will be for the second.
> >   */
> > 
> 
> My second thoughts: if we run `setkeycodes` to map, say, F10 as SysRq,
> don't we lose F10?

The fact that this patch adds a "new" sysrq key no matter what is a
non-starter, please think through the consequences of such a change...

So no, as-is, this change is not acceptable at all, and I would be
amazed if anyone would ship such a thing.

thanks,

greg k-h

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Andrzej Pietrasiewicz]

Hi Greg,

W dniu 05.11.2021 o 14:27, Greg Kroah-Hartman pisze:
> On Fri, Nov 05, 2021 at 02:01:23PM +0100, Andrzej Pietrasiewicz wrote:
>> Hi,
>>
>> W dniu 04.11.2021 o 15:17, Andrzej Pietrasiewicz pisze:
>>> Hi Maciej,
>>>
>>> W dniu 04.11.2021 o 14:13, Maciej W. Rozycki pisze:
>>>> On Thu, 4 Nov 2021, Maciej W. Rozycki wrote:
>>>>
>>>>>    The reason for this is with their more recent laptops Lenovo in their
>>>>> infinite wisdom have placed the <PrintScreen> key (which in a traditional
>>>>> PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their
>>>>> keyboards between the right <Alt> and <Ctrl> keys.  With thumbs not being
>>>>> as accurate as other fingers (and the overall misdesign of the keyboard
>>>>> and touchpad interface) you can imagine how often I have inadvertently hit
>>>>> <SysRq> combined with a letter key, wreaking havoc to my system (and of
>>>>> course I want to keep the key enabled for times when I do need it).
>>>>
>>>>    On second thoughts this can be disabled with `setkeycodes 54 0' once we
>>>> do have an alternative combination available.
>>>>
>>>
>>> Doesn't `setkeycodes` affect only one keyboard? What if there are more
>>> keyboards connected to a machine?
>>>
>>>   From drivers/tty/vt/keyboard.c:
>>>
>>> /*
>>>    * Translation of scancodes to keycodes. We set them on only the first
>>>    * keyboard in the list that accepts the scancode and keycode.
>>>    * Explanation for not choosing the first attached keyboard anymore:
>>>    *  USB keyboards for example have two event devices: one for all "normal"
>>>    *  keys and one for extra function keys (like "volume up", "make coffee",
>>>    *  etc.). So this means that scancodes for the extra function keys won't
>>>    *  be valid for the first event device, but will be for the second.
>>>    */
>>>
>>
>> My second thoughts: if we run `setkeycodes` to map, say, F10 as SysRq,
>> don't we lose F10?
> 
> The fact that this patch adds a "new" sysrq key no matter what is a
> non-starter, please think through the consequences of such a change...
> 

I wouldn't say this RFC adds a "new" sysrq no matter what. It does so only
when the input device (keyboard) does _not_ have SysRq key at all. So I would
say that this patch adds a replacement SysRq key if the SysRq key proper is
_physically_ absent. Which seems not such a bad thing to me. The problem I'm
trying to solve is exactly this: what to use as SysRq if there's no SysRq?

Andrzej

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Andrzej Pietrasiewicz]

Jiri, Greg,


W dniu 05.11.2021 o 15:06, Andrzej Pietrasiewicz pisze:
> Hi Greg,
> 
> W dniu 05.11.2021 o 14:27, Greg Kroah-Hartman pisze:
>> On Fri, Nov 05, 2021 at 02:01:23PM +0100, Andrzej Pietrasiewicz wrote:
>>> Hi,
>>>
>>> W dniu 04.11.2021 o 15:17, Andrzej Pietrasiewicz pisze:
>>>> Hi Maciej,
>>>>
>>>> W dniu 04.11.2021 o 14:13, Maciej W. Rozycki pisze:
>>>>> On Thu, 4 Nov 2021, Maciej W. Rozycki wrote:
>>>>>
>>>>>>    The reason for this is with their more recent laptops Lenovo in their
>>>>>> infinite wisdom have placed the <PrintScreen> key (which in a traditional
>>>>>> PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their
>>>>>> keyboards between the right <Alt> and <Ctrl> keys.  With thumbs not being
>>>>>> as accurate as other fingers (and the overall misdesign of the keyboard
>>>>>> and touchpad interface) you can imagine how often I have inadvertently hit
>>>>>> <SysRq> combined with a letter key, wreaking havoc to my system (and of
>>>>>> course I want to keep the key enabled for times when I do need it).
>>>>>
>>>>>    On second thoughts this can be disabled with `setkeycodes 54 0' once we
>>>>> do have an alternative combination available.
>>>>>
>>>>
>>>> Doesn't `setkeycodes` affect only one keyboard? What if there are more
>>>> keyboards connected to a machine?
>>>>
>>>>   From drivers/tty/vt/keyboard.c:
>>>>
>>>> /*
>>>>    * Translation of scancodes to keycodes. We set them on only the first
>>>>    * keyboard in the list that accepts the scancode and keycode.
>>>>    * Explanation for not choosing the first attached keyboard anymore:
>>>>    *  USB keyboards for example have two event devices: one for all "normal"
>>>>    *  keys and one for extra function keys (like "volume up", "make coffee",
>>>>    *  etc.). So this means that scancodes for the extra function keys won't
>>>>    *  be valid for the first event device, but will be for the second.
>>>>    */
>>>>
>>>
>>> My second thoughts: if we run `setkeycodes` to map, say, F10 as SysRq,
>>> don't we lose F10?
>>
>> The fact that this patch adds a "new" sysrq key no matter what is a
>> non-starter, please think through the consequences of such a change...
>>
> 
> I wouldn't say this RFC adds a "new" sysrq no matter what. It does so only
> when the input device (keyboard) does _not_ have SysRq key at all. So I would
> say that this patch adds a replacement SysRq key if the SysRq key proper is
> _physically_ absent. Which seems not such a bad thing to me. The problem I'm
> trying to solve is exactly this: what to use as SysRq if there's no SysRq?
> 

What approach is acceptable then? Any criteria other than "go guess"?
Is "connect an external keyboard" the _only_ choice Linux wants to offer
to its users in case of devices such as e.g. Chromebooks?

Regards,

Andrzej

Re: [RFC] tty/sysrq: Add alternative SysRq key

[Greg Kroah-Hartman]

On Mon, Nov 15, 2021 at 03:48:59PM +0100, Andrzej Pietrasiewicz wrote:
> Jiri, Greg,
> 
> 
> W dniu 05.11.2021 o 15:06, Andrzej Pietrasiewicz pisze:
> > Hi Greg,
> > 
> > W dniu 05.11.2021 o 14:27, Greg Kroah-Hartman pisze:
> > > On Fri, Nov 05, 2021 at 02:01:23PM +0100, Andrzej Pietrasiewicz wrote:
> > > > Hi,
> > > > 
> > > > W dniu 04.11.2021 o 15:17, Andrzej Pietrasiewicz pisze:
> > > > > Hi Maciej,
> > > > > 
> > > > > W dniu 04.11.2021 o 14:13, Maciej W. Rozycki pisze:
> > > > > > On Thu, 4 Nov 2021, Maciej W. Rozycki wrote:
> > > > > > 
> > > > > > >    The reason for this is with their more recent laptops Lenovo in their
> > > > > > > infinite wisdom have placed the <PrintScreen> key (which in a traditional
> > > > > > > PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their
> > > > > > > keyboards between the right <Alt> and <Ctrl> keys.  With thumbs not being
> > > > > > > as accurate as other fingers (and the overall misdesign of the keyboard
> > > > > > > and touchpad interface) you can imagine how often I have inadvertently hit
> > > > > > > <SysRq> combined with a letter key, wreaking havoc to my system (and of
> > > > > > > course I want to keep the key enabled for times when I do need it).
> > > > > > 
> > > > > >    On second thoughts this can be disabled with `setkeycodes 54 0' once we
> > > > > > do have an alternative combination available.
> > > > > > 
> > > > > 
> > > > > Doesn't `setkeycodes` affect only one keyboard? What if there are more
> > > > > keyboards connected to a machine?
> > > > > 
> > > > >   From drivers/tty/vt/keyboard.c:
> > > > > 
> > > > > /*
> > > > >    * Translation of scancodes to keycodes. We set them on only the first
> > > > >    * keyboard in the list that accepts the scancode and keycode.
> > > > >    * Explanation for not choosing the first attached keyboard anymore:
> > > > >    *  USB keyboards for example have two event devices: one for all "normal"
> > > > >    *  keys and one for extra function keys (like "volume up", "make coffee",
> > > > >    *  etc.). So this means that scancodes for the extra function keys won't
> > > > >    *  be valid for the first event device, but will be for the second.
> > > > >    */
> > > > > 
> > > > 
> > > > My second thoughts: if we run `setkeycodes` to map, say, F10 as SysRq,
> > > > don't we lose F10?
> > > 
> > > The fact that this patch adds a "new" sysrq key no matter what is a
> > > non-starter, please think through the consequences of such a change...
> > > 
> > 
> > I wouldn't say this RFC adds a "new" sysrq no matter what. It does so only
> > when the input device (keyboard) does _not_ have SysRq key at all. So I would
> > say that this patch adds a replacement SysRq key if the SysRq key proper is
> > _physically_ absent. Which seems not such a bad thing to me. The problem I'm
> > trying to solve is exactly this: what to use as SysRq if there's no SysRq?
> > 
> 
> What approach is acceptable then? Any criteria other than "go guess"?
> Is "connect an external keyboard" the _only_ choice Linux wants to offer
> to its users in case of devices such as e.g. Chromebooks?

I don't see how this patch only kicks in if a keyboard does not have a
sysrq key present given that you are allowing a different key to be used
as it also.

Anyway, it's an RFC, which can't be applied to the tree so I'll wait to
review it "for real" when you feel comfortable enough to submit it for
inclusion.

thanks,

greg k-h