Reset all keys on keyboard reset and also make sure to stop the CTRL+ALT+DEL sending on keyboard reset, fixes spurious "Keyboard not present" errors.

src/86box.c

@@ -1250,20 +1250,48 @@ pc_send_ca(uint16_t sc)
     if (keyboard_mode >= 0x81) {
         /* Use R-Alt because PS/55 DOS and OS/2 assign L-Alt Kanji */
         keyboard_input(1, 0x1D);  /*  Ctrl key pressed */
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(1, 0x138); /* R-Alt key pressed */
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(1, sc);
+        if (keyboard_get_in_reset())
+            return;
         usleep(50000);
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(0, sc);
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(0, 0x138); /* R-Alt key released */
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(0, 0x1D);  /*  Ctrl key released */
+        if (keyboard_get_in_reset())
+            return;
     } else {
         keyboard_input(1, 0x1D); /* Ctrl key pressed */
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(1, 0x38); /* Alt key pressed */
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(1, sc);
+        if (keyboard_get_in_reset())
+            return;
         usleep(50000);
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(0, sc);
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(0, 0x38); /* Alt key released */
+        if (keyboard_get_in_reset())
+            return;
         keyboard_input(0, 0x1D); /* Ctrl key released */
+        if (keyboard_get_in_reset())
+            return;
     }
 }
 

src/device/keyboard.c

@@ -68,6 +68,7 @@ static volatile uint8_t caps_lock   = 0;
 static volatile uint8_t num_lock     = 0;
 static volatile uint8_t scroll_lock  = 0;
 static volatile uint8_t kana_lock    = 0;
+static volatile uint8_t kbd_in_reset = 0;
 static uint8_t shift                 = 0;
 
 static int key5576mode = 0;
@@ -111,6 +112,7 @@ keyboard_init(void)
     scroll_lock  = 0;
     kana_lock    = 0;
     shift        = 0;
+    kbd_in_reset = 0;
 
     memset(recv_key, 0x00, sizeof(recv_key));
     memset(recv_key_ui, 0x00, sizeof(recv_key));
@@ -343,9 +345,9 @@ void
 keyboard_all_up(void)
 {
     for (unsigned short i = 0; i < 0x200; i++) {
-        if (recv_key_ui[i]) {
+        if (recv_key_ui[i])
             recv_key_ui[i] = 0;
-        }
+
         if (recv_key[i]) {
             recv_key[i] = 0;
             key_process(i, 0);
@@ -353,6 +355,18 @@ keyboard_all_up(void)
     }
 }
 
+void
+keyboard_set_in_reset(uint8_t in_reset)
+{
+    kbd_in_reset = in_reset;
+}
+
+uint8_t
+keyboard_get_in_reset(void)
+{
+    return kbd_in_reset;
+}
+
 static uint8_t
 keyboard_do_break(uint16_t scan)
 {

src/device/keyboard_at.c

@@ -3476,7 +3476,10 @@ keyboard_at_bat(void *priv)
 
         keyboard_scan = 1;
 
+        keyboard_all_up();
         keyboard_update_states(0, 0, 0, 0);
+
+        keyboard_set_in_reset(0);
         kbc_at_dev_queue_add(dev, 0xaa, 0);
     } else {
         bat_counter--;
@@ -3714,6 +3717,7 @@ keyboard_at_write(void *priv)
                 break;
 
             case 0xff: /* reset */
+                keyboard_set_in_reset(1);
                 kbc_at_dev_reset(dev, 1);
                 bat_counter = 1000;
                 break;

src/include/86box/keyboard.h

@@ -273,6 +273,8 @@ extern void     keyboard_input(int down, uint16_t scan);
 extern void     keyboard_all_up(void);
 extern void     keyboard_update_states(uint8_t cl, uint8_t nl, uint8_t sl, uint8_t kl);
 extern uint8_t  keyboard_get_shift(void);
+extern void     keyboard_set_in_reset(uint8_t in_reset);
+extern uint8_t  keyboard_get_in_reset(void);
 extern void     keyboard_get_states(uint8_t *cl, uint8_t *nl, uint8_t *sl, uint8_t *kl);
 extern void     keyboard_set_states(uint8_t cl, uint8_t nl, uint8_t sl);
 extern int      keyboard_recv(uint16_t key);