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Date:   Fri, 15 Oct 2021 16:37:31 +0800
From:   lianzhi chang <changlianzhi@...ontech.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-input@...r.kernel.org,
        lianzhi chang <changlianzhi@...ontech.com>
Subject: [PATCH] input&tty: Fix the keyboard led light display problem

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@...ontech.com>
---
The latest changes:
(1) Move the definition of ledstate to the input module (/drivers/input/input.c), 
and set or get its value through the input_update_ledstate and input_get_ledstate 
functions.
(2) To update the ledstate reference in keyboard.c, you must first get the value 
through input_get_ledstate.
(3) Other necessary changes

 drivers/input/input.c     | 46 ++++++++++++++++++++++++++++++++++++++-
 drivers/tty/vt/keyboard.c | 19 ++++++++++++++--
 include/linux/input.h     |  3 +++
 3 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/drivers/input/input.c b/drivers/input/input.c
index ccaeb2426385..8c0ef947ac34 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -37,6 +37,11 @@ static DEFINE_IDA(input_ida);
 static LIST_HEAD(input_dev_list);
 static LIST_HEAD(input_handler_list);
 
+#define VC_SCROLLOCK	0	/* scroll-lock mode */
+#define VC_NUMLOCK	1	/* numeric lock mode */
+#define VC_CAPSLOCK	2	/* capslock mode */
+static unsigned int ledstate = -1U;			/* undefined */
+
 /*
  * input_mutex protects access to both input_dev_list and input_handler_list.
  * This also causes input_[un]register_device and input_[un]register_handler
@@ -472,8 +477,12 @@ void input_inject_event(struct input_handle *handle,
 
 		rcu_read_lock();
 		grab = rcu_dereference(dev->grab);
-		if (!grab || grab == handle)
+		if (!grab || grab == handle) {
 			input_handle_event(dev, type, code, value);
+
+			if (type == EV_LED && code <= LED_SCROLLL)
+				input_update_ledstate(code, value);
+		}
 		rcu_read_unlock();
 
 		spin_unlock_irqrestore(&dev->event_lock, flags);
@@ -481,6 +490,41 @@ void input_inject_event(struct input_handle *handle,
 }
 EXPORT_SYMBOL(input_inject_event);
 
+void input_update_ledstate(unsigned int flag, unsigned int value)
+{
+	unsigned int bit;
+
+	switch (flag) {
+	case LED_NUML:
+		bit = VC_NUMLOCK;
+		break;
+	case LED_CAPSL:
+		bit = VC_CAPSLOCK;
+		break;
+	case LED_SCROLLL:
+		bit = VC_SCROLLOCK;
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	if (ledstate == -1U)
+		ledstate = 0;
+
+	if (value)
+		ledstate |= BIT(bit);
+	else
+		ledstate &= ~BIT(bit);
+}
+EXPORT_SYMBOL(input_update_ledstate);
+
+unsigned int input_get_ledstate(void)
+{
+	return ledstate;
+}
+EXPORT_SYMBOL(input_get_ledstate);
+
 /**
  * input_alloc_absinfo - allocates array of input_absinfo structs
  * @dev: the input device emitting absolute events
diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index c7fbbcdcc346..0cfccb1d7992 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -151,7 +151,6 @@ static bool rep;			/* flag telling character repeat */
 
 static int shift_state = 0;
 
-static unsigned int ledstate = -1U;			/* undefined */
 static unsigned char ledioctl;
 
 /*
@@ -1021,10 +1020,14 @@ struct kbd_led_trigger {
 
 static int kbd_led_trigger_activate(struct led_classdev *cdev)
 {
+	unsigned int ledstate;
+
 	struct kbd_led_trigger *trigger =
 		container_of(cdev->trigger, struct kbd_led_trigger, trigger);
 
 	tasklet_disable(&keyboard_tasklet);
+
+	ledstate = input_get_ledstate();
 	if (ledstate != -1U)
 		led_trigger_event(&trigger->trigger,
 				  ledstate & trigger->mask ?
@@ -1137,6 +1140,10 @@ static void kbd_init_leds(void)
  */
 static unsigned char getledstate(void)
 {
+	unsigned int ledstate;
+
+	ledstate = input_get_ledstate();
+
 	return ledstate & 0xff;
 }
 
@@ -1248,16 +1255,21 @@ void vt_kbd_con_stop(unsigned int console)
 static void kbd_bh(struct tasklet_struct *unused)
 {
 	unsigned int leds;
+	unsigned int ledstate;
 	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();
+	ledstate = input_get_ledstate();
 	leds |= (unsigned int)kbd->lockstate << 8;
 	spin_unlock_irqrestore(&led_lock, flags);
 
 	if (leds != ledstate) {
 		kbd_propagate_led_state(ledstate, leds);
-		ledstate = leds;
 	}
 }
 
@@ -1604,8 +1616,11 @@ static void kbd_disconnect(struct input_handle *handle)
  */
 static void kbd_start(struct input_handle *handle)
 {
+	unsigned int ledstate;
+
 	tasklet_disable(&keyboard_tasklet);
 
+	ledstate = input_get_ledstate();
 	if (ledstate != -1U)
 		kbd_update_leds_helper(handle, &ledstate);
 
diff --git a/include/linux/input.h b/include/linux/input.h
index 0354b298d874..0e0ba53a9cc7 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -420,6 +420,9 @@ ktime_t *input_get_timestamp(struct input_dev *dev);
 void input_event(struct input_dev *dev, unsigned int type, unsigned int code, int value);
 void input_inject_event(struct input_handle *handle, unsigned int type, unsigned int code, int value);
 
+void input_update_ledstate(unsigned int flag, unsigned int value);
+unsigned int input_get_ledstate(void);
+
 static inline void input_report_key(struct input_dev *dev, unsigned int code, int value)
 {
 	input_event(dev, EV_KEY, code, !!value);
-- 
2.20.1



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