1 files changed, 107 insertions, 0 deletions
diff --git a/config/grub/default/patches/0003-keyboardfix/0001-at_keyboard-coreboot-force-scancodes2-translate.patch b/config/grub/default/patches/0003-keyboardfix/0001-at_keyboard-coreboot-force-scancodes2-translate.patch
new file mode 100644
index 00000000..21e8630b
--- /dev/null
+++ b/config/grub/default/patches/0003-keyboardfix/0001-at_keyboard-coreboot-force-scancodes2-translate.patch
@@ -0,0 +1,107 @@
+From 96c0bbe5d406b616360a7fce7cee67d7692c0d6d Mon Sep 17 00:00:00 2001
+From: Leah Rowe <leah@libreboot.org>
+Date: Mon, 30 Oct 2023 22:19:21 +0000
+Subject: [PATCH 1/1] at_keyboard coreboot: force scancodes2+translate
+
+Scan code set 2 with translation should be assumed in
+every case, as the default starting position.
+
+However, GRUB is trying to detect and use other modes
+such as set 2 without translation, or set 1 without
+translation from set 2; it also detects no-mode and
+assumes mode 1, on really old keyboards.
+
+The current behaviour has been retained, for everything
+except GRUB_MACHINE_COREBOOT; for the latter, scan code
+set 2 with translation is hardcoded, and forced in code.
+
+This is required to make keyboard initialisation work on
+the MEC5035 EC used by the Dell Latitude E6400, when
+running GRUB as a coreboot payload on that laptop. The
+EC reports scancode set 2 with translation when probed,
+but actually only outputs scancode set 1.
+
+Since GRUB is attempting to use it without translation,
+and since the machine reports set 2 with translation,
+but only ever outputs set 1 scancodes, this results in
+wrong keypresses for every key.
+
+This fix fixed that, by forcing set 2 with translation,
+treating it as set 1, but only on coreboot. This is the
+same behaviour used in GNU+Linux systems and SeaBIOS.
+With this change, GRUB keyboard initialisation now works
+just fine on those machines.
+
+This has *also* been tested on other coreboot machines
+running GRUB; several HP EliteBooks, ThinkPads and
+Dell Precision T1650. All seems to work just fine.
+
+Signed-off-by: Leah Rowe <leah@libreboot.org>
+---
+ grub-core/term/at_keyboard.c | 20 ++++++++++++++++++--
+ 1 file changed, 18 insertions(+), 2 deletions(-)
+
+diff --git a/grub-core/term/at_keyboard.c b/grub-core/term/at_keyboard.c
+index f8a129eb7..8207225c2 100644
+--- a/grub-core/term/at_keyboard.c
++++ b/grub-core/term/at_keyboard.c
+@@ -138,6 +138,7 @@ write_mode (int mode)
+   return (i != GRUB_AT_TRIES);
+ }
+ 
++#if !defined (GRUB_MACHINE_COREBOOT)
+ static int
+ query_mode (void)
+ {
+@@ -161,10 +162,12 @@ query_mode (void)
+     return 3;
+   return 0;
+ }
++#endif
+ 
+ static void
+ set_scancodes (void)
+ {
++#if !defined (GRUB_MACHINE_COREBOOT)
+   /* You must have visited computer museum. Keyboard without scancode set
+      knowledge. Assume XT. */
+   if (!grub_keyboard_orig_set)
+@@ -173,20 +176,33 @@ set_scancodes (void)
+       ps2_state.current_set = 1;
+       return;
+     }
++#endif
+ 
+ #if !USE_SCANCODE_SET
+   ps2_state.current_set = 1;
+   return;
+-#else
++#endif
+ 
++#if defined (GRUB_MACHINE_COREBOOT)
++  /* enable translation */
++  grub_keyboard_controller_write (grub_keyboard_controller_orig
++				  & ~KEYBOARD_AT_DISABLE);
++#else
++  /* if not coreboot, disable translation and try mode 2 first, before 1 */
+   grub_keyboard_controller_write (grub_keyboard_controller_orig
+ 				  & ~KEYBOARD_AT_TRANSLATE
+ 				  & ~KEYBOARD_AT_DISABLE);
++#endif
+ 
+   keyboard_controller_wait_until_ready ();
+   grub_outb (KEYBOARD_COMMAND_ENABLE, KEYBOARD_REG_DATA);
+-
+   write_mode (2);
++
++#if defined (GRUB_MACHINE_COREBOOT)
++  /* mode 2 with translation, so make grub treat as set 1 */
++  ps2_state.current_set = 1;
++#else
++  /* if not coreboot, translation isn't set; test 2 and fall back to 1 */
+   ps2_state.current_set = query_mode ();
+   grub_dprintf ("atkeyb", "returned set %d\n", ps2_state.current_set);
+   if (ps2_state.current_set == 2)
+-- 
+2.39.2
+