[PATCH] at_keyboard.c: add timeout to fix hang on hp elitebooks

[Riku Viitanen]

This fixes GRUB on Coreboot on HP EliteBooks by implementing
a 200ms timeout. GRUB used to hang. See: https://ticket.coreboot.org/issues/141
---
 grub-core/term/at_keyboard.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/grub-core/term/at_keyboard.c b/grub-core/term/at_keyboard.c
index 597111077..28d1d0a77 100644
--- a/grub-core/term/at_keyboard.c
+++ b/grub-core/term/at_keyboard.c
@@ -42,7 +42,16 @@ keyboard_controller_wait_until_ready (void)
 {
   /* 50 us would be enough but our current time resolution is 1ms.  */
   grub_millisleep (1);
-  while (! KEYBOARD_COMMAND_ISREADY (grub_inb (KEYBOARD_REG_STATUS)));
+
+  unsigned i = 200;
+  while (! KEYBOARD_COMMAND_ISREADY (grub_inb (KEYBOARD_REG_STATUS))) {
+    grub_millisleep (1);
+
+    /* Timeout */
+    if (! i--) {
+      break;
+    }
+  }
 }
 
 static grub_uint8_t
-- 
2.40.0