[[PATCH v4]] tty: Fix the keyboard led light display problem

[[PATCH v4]] tty: Fix the keyboard led light display problem

[lianzhi chang]

Switching from the desktop environment to the tty environment,
the state of the keyboard led lights and the state of the keyboard
lock are inconsistent. This is because the attribute kb->kbdmode
of the tty bound in the desktop environment (xorg) is set to
VC_OFF, which causes the ledstate and kb->ledflagstate
values of the bound tty to always be 0, which causes the switch
from the desktop When to the tty environment, the LED light
status is inconsistent with the keyboard lock status.

Signed-off-by: lianzhi chang <changlianzhi@uniontech.com>
---
 v2-->v3:
 (1) Abandon the previous modification plan.
 (2) Added the kbd_update_ledstate function, this function gets the 
 latest state of the led from the input device, and then synchronizes
 it to the ledstate. The kbd_event function calls it.
 (3) When the tty's kbdmode==VC_OFF, the tty does not set the keyboard light (modify the kbd_bh function).
 v3-->v4:
 Correct the subject
 
 drivers/tty/vt/keyboard.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index c7fbbcdcc346..5fcdd1805b4d 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -1130,6 +1130,22 @@ static void kbd_init_leds(void)
 
 #endif
 
+static void kbd_update_ledstate(struct input_dev *dev)
+{
+	unsigned long leds = (unsigned long)ledstate;
+	
+	if (test_bit(EV_LED, dev->evbit)) {
+		if (ledstate == -1U)
+			ledstate = 0;
+		if (!!test_bit(LED_NUML, dev->led) != !!test_bit(VC_NUMLOCK, &leds))
+			ledstate ^= BIT(VC_NUMLOCK);
+		if (!!test_bit(LED_CAPSL, dev->led) != !!test_bit(VC_CAPSLOCK, &leds))
+			ledstate ^= BIT(VC_CAPSLOCK);
+		if (!!test_bit(LED_SCROLLL, dev->led) != !!test_bit(VC_SCROLLOCK, &leds))
+			ledstate ^= BIT(VC_SCROLLOCK); 
+	}
+}
+
 /*
  * The leds display either (i) the status of NumLock, CapsLock, ScrollLock,
  * or (ii) whatever pattern of lights people want to show using KDSETLED,
@@ -1249,6 +1265,10 @@ static void kbd_bh(struct tasklet_struct *unused)
 {
 	unsigned int leds;
 	unsigned long flags;
+	struct kbd_struct *kb = kbd_table + fg_console;
+
+	if (kb->kbdmode == VC_OFF)
+		return;
 
 	spin_lock_irqsave(&led_lock, flags);
 	leds = getleds();
@@ -1524,6 +1544,8 @@ static void kbd_event(struct input_handle *handle, unsigned int event_type,
 	/* We are called with interrupts disabled, just take the lock */
 	spin_lock(&kbd_event_lock);
 
+	kbd_update_ledstate(handle->dev);
+
 	if (event_type == EV_MSC && event_code == MSC_RAW &&
 			kbd_is_hw_raw(handle->dev))
 		kbd_rawcode(value);
-- 
2.20.1

Re: [[PATCH v4]] tty: Fix the keyboard led light display problem

[Andy Shevchenko]

On Wed, Oct 20, 2021 at 03:44:23PM +0800, lianzhi chang wrote:
> Switching from the desktop environment to the tty environment,
> the state of the keyboard led lights and the state of the keyboard
> lock are inconsistent. This is because the attribute kb->kbdmode
> of the tty bound in the desktop environment (xorg) is set to

Xorg

> VC_OFF, which causes the ledstate and kb->ledflagstate
> values of the bound tty to always be 0, which causes the switch
> from the desktop When to the tty environment, the LED light
> status is inconsistent with the keyboard lock status.

As per Dmitry's remark you need elaborate in the commit message why you can't
do as he suggested.

...

Accordingly to what I see the below has some trailing white spaces,
can you remove them?

> +static void kbd_update_ledstate(struct input_dev *dev)
> +{

> +	unsigned long leds = (unsigned long)ledstate;

Why casting?

> +	
> +	if (test_bit(EV_LED, dev->evbit)) {
> +		if (ledstate == -1U)

This is a bit weird, but I see that this should be changed in entire module.

> +			ledstate = 0;
> +		if (!!test_bit(LED_NUML, dev->led) != !!test_bit(VC_NUMLOCK, &leds))
> +			ledstate ^= BIT(VC_NUMLOCK);
> +		if (!!test_bit(LED_CAPSL, dev->led) != !!test_bit(VC_CAPSLOCK, &leds))
> +			ledstate ^= BIT(VC_CAPSLOCK);
> +		if (!!test_bit(LED_SCROLLL, dev->led) != !!test_bit(VC_SCROLLOCK, &leds))
> +			ledstate ^= BIT(VC_SCROLLOCK); 
> +	}
> +}

...

Can this...

>  	unsigned int leds;
>  	unsigned long flags;
> +	struct kbd_struct *kb = kbd_table + fg_console;
> +
> +	if (kb->kbdmode == VC_OFF)
> +		return;

...be written as

	struct kbd_struct *kb;
	unsigned int leds;
	unsigned long flags;

	kb = kbd_table + fg_console;
	if (kb->kbdmode == VC_OFF)
		return;

?

-- 
With Best Regards,
Andy Shevchenko