From: Julian Andres Klode <julian.klode@canonical.com>
Date: Tue, 25 Jul 2023 15:35:52 +0200
Subject: Add configure option to reduce visual clutter at boot time

If this option is enabled, then do all of the following:

Don't display introductory message about line editing unless we're
actually offering a shell prompt.  (This is believed to be a workaround
for a different bug.  We'll go with this for now, but will drop this in
favour of a better fix upstream if somebody figures out what that is.)

Don't clear the screen just before booting if we never drew the menu in
the first place.

Remove verbose messages printed before reading configuration.  In some
ways this is awkward because it makes debugging harder, but it's a
requirement for a smooth-looking boot process; we may be able to do
better in future.  Upstream doesn't want this, though.

Disable the cursor as well, for similar reasons of tidiness.

Suppress kernel/initrd progress messages, except in recovery mode.

Suppress "GRUB loading" message unless Shift is held down.  Upstream
doesn't want this, as it makes debugging harder.  Ubuntu wants it to
provide a cleaner boot experience.

Author: Will Thompson <will@willthompson.co.uk>
Bug-Ubuntu: https://bugs.launchpad.net/bugs/386922
Bug-Ubuntu: https://bugs.launchpad.net/bugs/861048
Forwarded: (partial) http://lists.gnu.org/archive/html/grub-devel/2009-09/msg00056.html
Last-Update: 2021-09-24

Patch-Name: maybe-quiet.patch
---
 config.h.in                       |  2 ++
 configure.ac                      | 16 ++++++++++++++++
 grub-core/boot/i386/pc/boot.S     | 11 +++++++++++
 grub-core/boot/i386/pc/diskboot.S | 26 ++++++++++++++++++++++++++
 grub-core/kern/main.c             | 17 +++++++++++++++++
 grub-core/kern/rescue_reader.c    |  6 ++++--
 grub-core/normal/main.c           | 11 +++++++++++
 grub-core/normal/menu.c           | 15 +++++++++++++--
 util/grub.d/10_linux.in           | 17 +++++++++++++----
 9 files changed, 113 insertions(+), 8 deletions(-)

diff --git a/config.h.in b/config.h.in
index 9b1d399..9d6f369 100644
--- a/config.h.in
+++ b/config.h.in
@@ -16,6 +16,8 @@
 /* Define to 1 to enable disk cache statistics.  */
 #define DISK_CACHE_STATS @DISK_CACHE_STATS@
 #define BOOT_TIME_STATS @BOOT_TIME_STATS@
+/* Define to 1 to make GRUB quieter at boot time.  */
+#define QUIET_BOOT @QUIET_BOOT@
 
 /* We don't need those.  */
 #define MINILZO_CFG_SKIP_LZO_PTR 1
diff --git a/configure.ac b/configure.ac
index b880677..b34cbde 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2128,6 +2128,17 @@ else
 fi
 AC_SUBST([UBUNTU_RECOVERY])
 
+AC_ARG_ENABLE([quiet-boot],
+              [AS_HELP_STRING([--enable-quiet-boot],
+                              [emit fewer messages at boot time (default=no)])],
+              [], [enable_quiet_boot=no])
+if test x"$enable_quiet_boot" = xyes ; then
+  QUIET_BOOT=1
+else
+  QUIET_BOOT=0
+fi
+AC_SUBST([QUIET_BOOT])
+
 LIBS=""
 
 AC_SUBST([FONT_SOURCE])
@@ -2409,5 +2420,10 @@ echo "With stack smashing protector: Yes"
 else
 echo "With stack smashing protector: No"
 fi
+if [ x"$enable_quiet_boot" = xyes ]; then
+echo With quiet boot: Yes
+else
+echo With quiet boot: No
+fi
 echo "*******************************************************"
 ]
diff --git a/grub-core/boot/i386/pc/boot.S b/grub-core/boot/i386/pc/boot.S
index 2bd0b2d..b0c0f22 100644
--- a/grub-core/boot/i386/pc/boot.S
+++ b/grub-core/boot/i386/pc/boot.S
@@ -19,6 +19,9 @@
 
 #include <grub/symbol.h>
 #include <grub/machine/boot.h>
+#if QUIET_BOOT && !defined(HYBRID_BOOT)
+#include <grub/machine/memory.h>
+#endif
 
 /*
  *  defines for the code go here
@@ -249,9 +252,17 @@ real_start:
 	/* save drive reference first thing! */
 	pushw	%dx
 
+#if QUIET_BOOT && !defined(HYBRID_BOOT)
+	/* is either shift key held down? */
+	movw	$(GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR + 0x17), %bx
+	testb	$3, (%bx)
+	jz	2f
+#endif
+
 	/* print a notification message on the screen */
 	MSG(notification_string)
 
+2:
 	/* set %si to the disk address packet */
 	movw	$disk_address_packet, %si
 
diff --git a/grub-core/boot/i386/pc/diskboot.S b/grub-core/boot/i386/pc/diskboot.S
index c1addc0..9b6d7a7 100644
--- a/grub-core/boot/i386/pc/diskboot.S
+++ b/grub-core/boot/i386/pc/diskboot.S
@@ -18,6 +18,9 @@
 
 #include <grub/symbol.h>
 #include <grub/machine/boot.h>
+#if QUIET_BOOT
+#include <grub/machine/memory.h>
+#endif
 
 /*
  *  defines for the code go here
@@ -25,6 +28,12 @@
 
 #define MSG(x)	movw $x, %si; call LOCAL(message)
 
+#if QUIET_BOOT
+#define SILENT(x)	call LOCAL(check_silent); jz LOCAL(x)
+#else
+#define SILENT(x)
+#endif
+
 	.file	"diskboot.S"
 
 	.text
@@ -50,11 +59,14 @@ _start:
 	/* save drive reference first thing! */
 	pushw	%dx
 
+	SILENT(after_notification_string)
+
 	/* print a notification message on the screen */
 	pushw	%si
 	MSG(notification_string)
 	popw	%si
 
+LOCAL(after_notification_string):
 	/* this sets up for the first run through "bootloop" */
 	movw	$LOCAL(firstlist), %di
 
@@ -279,7 +291,10 @@ LOCAL(copy_buffer):
 	/* restore addressing regs and print a dot with correct DS
 	   (MSG modifies SI, which is saved, and unused AX and BX) */
 	popw	%ds
+	SILENT(after_notification_step)
 	MSG(notification_step)
+
+LOCAL(after_notification_step):
 	popa
 
 	/* check if finished with this dataset */
@@ -295,8 +310,11 @@ LOCAL(copy_buffer):
 /* END OF MAIN LOOP */
 
 LOCAL(bootit):
+	SILENT(after_notification_done)
 	/* print a newline */
 	MSG(notification_done)
+
+LOCAL(after_notification_done):
 	popw	%dx	/* this makes sure %dl is our "boot" drive */
 	ljmp	$0, $(GRUB_BOOT_MACHINE_KERNEL_ADDR + 0x200)
 
@@ -320,6 +338,14 @@ LOCAL(general_error):
 /* go here when you need to stop the machine hard after an error condition */
 LOCAL(stop):	jmp	LOCAL(stop)
 
+#if QUIET_BOOT
+LOCAL(check_silent):
+	/* is either shift key held down? */
+	movw	$(GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR + 0x17), %bx
+	testb	$3, (%bx)
+	ret
+#endif
+
 notification_string:	.asciz "loading"
 
 notification_step:	.asciz "."
diff --git a/grub-core/kern/main.c b/grub-core/kern/main.c
index 143a232..60eed47 100644
--- a/grub-core/kern/main.c
+++ b/grub-core/kern/main.c
@@ -303,6 +303,10 @@ reclaim_module_space (void)
 void __attribute__ ((noreturn))
 grub_main (void)
 {
+#if QUIET_BOOT
+  struct grub_term_output *term;
+#endif
+
 #ifdef GRUB_STACK_PROTECTOR
   /*
    * This call should only be made from a function that does not return because
@@ -318,12 +322,18 @@ grub_main (void)
 
   grub_boot_time ("After machine init.");
 
+#if QUIET_BOOT
+  /* Disable the cursor until we need it.  */
+  FOR_ACTIVE_TERM_OUTPUTS(term)
+    grub_term_setcursor (term, 0);
+#else
   /* This breaks flicker-free boot on EFI systems, so disable it there. */
 #ifndef GRUB_MACHINE_EFI
   /* Hello.  */
   grub_setcolorstate (GRUB_TERM_COLOR_HIGHLIGHT);
   grub_printf ("Welcome to GRUB!\n\n");
   grub_setcolorstate (GRUB_TERM_COLOR_STANDARD);
+#endif
 #endif
 
   /* Init verifiers API. */
@@ -366,5 +376,12 @@ grub_main (void)
   grub_boot_time ("After execution of embedded config. Attempt to go to normal mode");
 
   grub_load_normal_mode ();
+
+#if QUIET_BOOT
+  /* If we have to enter rescue mode, enable the cursor again.  */
+  FOR_ACTIVE_TERM_OUTPUTS(term)
+    grub_term_setcursor (term, 1);
+#endif
+
   grub_rescue_run ();
 }
diff --git a/grub-core/kern/rescue_reader.c b/grub-core/kern/rescue_reader.c
index a71ada8..932254a 100644
--- a/grub-core/kern/rescue_reader.c
+++ b/grub-core/kern/rescue_reader.c
@@ -78,6 +78,10 @@ grub_rescue_read_line (char **line, int cont,
 void __attribute__ ((noreturn))
 grub_rescue_run (void)
 {
+#if QUIET_BOOT
+  grub_printf ("Entering rescue mode...\n");
+#endif
+
   /* Stall if the CLI has been disabled */
   if (grub_is_cli_disabled () || grub_is_cli_need_auth ())
     {
@@ -91,8 +95,6 @@ grub_rescue_run (void)
       while (1);
     }
 
-  grub_printf ("Entering rescue mode...\n");
-
   while (1)
     {
       char *line;
diff --git a/grub-core/normal/main.c b/grub-core/normal/main.c
index 96abfda..c363874 100644
--- a/grub-core/normal/main.c
+++ b/grub-core/normal/main.c
@@ -408,6 +408,15 @@ static grub_err_t
 grub_normal_read_line_real (char **line, int cont, int nested)
 {
   const char *prompt;
+#if QUIET_BOOT
+  static int displayed_intro;
+
+  if (! displayed_intro)
+    {
+      grub_normal_reader_init (nested);
+      displayed_intro = 1;
+    }
+#endif
 
   if (cont)
     /* TRANSLATORS: it's command line prompt.  */
@@ -464,7 +473,9 @@ grub_cmdline_run (int nested, int force_auth)
       return;
     }
 
+#if !QUIET_BOOT
   grub_normal_reader_init (nested);
+#endif
 
   while (1)
     {
diff --git a/grub-core/normal/menu.c b/grub-core/normal/menu.c
index b946c83..1b8b91b 100644
--- a/grub-core/normal/menu.c
+++ b/grub-core/normal/menu.c
@@ -815,14 +815,18 @@ run_menu (grub_menu_t menu, int nested, int *auto_boot, int *notify_boot)
 static void
 notify_booting (grub_menu_entry_t entry, void *userdata)
 {
+#if !QUIET_BOOT
   int *notify_boot = userdata;
-
   if (*notify_boot)
     {
       grub_printf ("  ");
       grub_printf_ (N_("Booting `%s'"), entry->title);
       grub_printf ("\n\n");
     }
+#else
+  (void) userdata;
+  (void) entry;
+#endif
 }
 
 /* Callback invoked when a default menu entry executed because of a timeout
@@ -871,6 +875,9 @@ show_menu (grub_menu_t menu, int nested, int autobooted)
       grub_menu_entry_t e;
       int auto_boot;
       int notify_boot;
+#if QUIET_BOOT
+      int initial_timeout = grub_menu_get_timeout ();
+#endif
 
       boot_entry = run_menu (menu, nested, &auto_boot, &notify_boot);
       if (boot_entry < 0)
@@ -885,7 +892,11 @@ show_menu (grub_menu_t menu, int nested, int autobooted)
 					 &execution_callback, &notify_boot);
       else
 	{
-	  grub_cls ();
+#if QUIET_BOOT
+          /* Only clear the screen if we drew the menu in the first place.  */
+          if (initial_timeout != 0)
+#endif
+	    grub_cls ();
 	  grub_menu_execute_entry (e, 0);
 	}
       if (autobooted)
diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
index 19a2251..7ef8672 100644
--- a/util/grub.d/10_linux.in
+++ b/util/grub.d/10_linux.in
@@ -21,6 +21,7 @@ prefix="@prefix@"
 exec_prefix="@exec_prefix@"
 datarootdir="@datarootdir@"
 ubuntu_recovery="@UBUNTU_RECOVERY@"
+quiet_boot="@QUIET_BOOT@"
 
 . "$pkgdatadir/grub-mkconfig_lib"
 
@@ -154,20 +155,28 @@ linux_entry ()
     fi
     printf '%s\n' "${prepare_boot_cache}" | sed "s/^/$submenu_indentation/"
   fi
-  message="$(gettext_printf "Loading Linux %s ..." ${version})"
-  sed "s/^/$submenu_indentation/" << EOF
+  if [ x"$quiet_boot" = x0 ] || [ x"$type" != xsimple ]; then
+    message="$(gettext_printf "Loading Linux %s ..." ${version})"
+    sed "s/^/$submenu_indentation/" << EOF
 	echo	'$(echo "$message" | grub_quote)'
+EOF
+  fi
+  sed "s/^/$submenu_indentation/" << EOF
 	linux	${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro ${args}
 EOF
   if test -n "${initrd}" ; then
     # TRANSLATORS: ramdisk isn't identifier. Should be translated.
-    message="$(gettext_printf "Loading initial ramdisk ...")"
+    if [ x"$quiet_boot" = x0 ] || [ x"$type" != xsimple ]; then
+      message="$(gettext_printf "Loading initial ramdisk ...")"
+      sed "s/^/$submenu_indentation/" << EOF
+	echo	'$(echo "$message" | grub_quote)'
+EOF
+    fi
     initrd_path=
     for i in ${initrd}; do
       initrd_path="${initrd_path} ${rel_dirname}/${i}"
     done
     sed "s/^/$submenu_indentation/" << EOF
-	echo	'$(echo "$message" | grub_quote)'
 	initrd	$(echo $initrd_path)
 EOF
   fi