[SeaBIOS] [PATCH v3 1/2] boot.c: delay exiting boot if menu key is ESC

[Paolo Bonzini]

If the menu key is ESC, do not restart boot unless
1.5 seconds have passed.  Otherwise users (trained by years of
repeatedly hitting keys to enter the BIOS) will end up hitting ESC
multiple times and immediately booting the primary boot device.

Suggested-by: Matt DeVillier 
Signed-off-by: Paolo Bonzini 
---
 src/boot.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/boot.c b/src/boot.c
index f23e9e1..3aab8d4 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -486,9 +486,15 @@ interactive_bootmenu(void)
                , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
     }

-    // Get key press
+    // Get key press.  If the menu key is ESC, do not restart boot unless
+    // 1.5 seconds have passed.  Otherwise users (trained by years of
+    // repeatedly hitting keys to enter the BIOS) will end up hitting ESC
+    // multiple times and immediately booting the primary boot device.
+    int esc_accepted_time = irqtimer_calc(menukey == 1 ? 1500 : 0);
     for (;;) {
         scan_code = get_keystroke(1000);
+        if (scan_code == 1 && !irqtimer_check(esc_accepted_time))
+            continue;
         if (scan_code >= 1 && scan_code <= maxmenu+1)
             break;
     }