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

@@ -12,6 +12,8 @@
 /* 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

configure.ac

@@ -1915,6 +1915,17 @@ 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])
@@ -2177,5 +2188,10 @@ 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 "*******************************************************"
 ]

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
 

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 "."

grub-core/kern/main.c

@@ -265,15 +265,25 @@ reclaim_module_space (void)
 void __attribute__ ((noreturn))
 grub_main (void)
 {
+#if QUIET_BOOT
+  struct grub_term_output *term;
+#endif
+
   /* First of all, initialize the machine.  */
   grub_machine_init ();
 
   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
   /* Hello.  */
   grub_setcolorstate (GRUB_TERM_COLOR_HIGHLIGHT);
   grub_printf ("Welcome to GRUB!\n\n");
   grub_setcolorstate (GRUB_TERM_COLOR_STANDARD);
+#endif
 
   /* Init verifiers API. */
   grub_verifiers_init ();
@@ -312,5 +322,12 @@ 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 ();
 }

grub-core/kern/rescue_reader.c

@@ -78,7 +78,9 @@ 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
 
   while (1)
     {

grub-core/normal/main.c

@@ -407,6 +407,15 @@ 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.  */
@@ -459,7 +468,9 @@ grub_cmdline_run (int nested, int force_auth)
       return;
     }
 
+#if !QUIET_BOOT
   grub_normal_reader_init (nested);
+#endif
 
   while (1)
     {

grub-core/normal/menu.c

@@ -807,12 +807,18 @@ run_menu (grub_menu_t menu, int nested, int *auto_boot)
 
 /* Callback invoked immediately before a menu entry is executed.  */
 static void
-notify_booting (grub_menu_entry_t entry,
+notify_booting (grub_menu_entry_t entry
+#if QUIET_BOOT
+		__attribute__((unused))
+#endif
+		,
 		void *userdata __attribute__((unused)))
 {
+#if !QUIET_BOOT
   grub_printf ("  ");
   grub_printf_ (N_("Booting `%s'"), entry->title);
   grub_printf ("\n\n");
+#endif
 }
 
 /* Callback invoked when a default menu entry executed because of a timeout
@@ -860,6 +866,9 @@ show_menu (grub_menu_t menu, int nested, int autobooted)
       int boot_entry;
       grub_menu_entry_t e;
       int auto_boot;
+#if QUIET_BOOT
+      int initial_timeout = grub_menu_get_timeout ();
+#endif
 
       boot_entry = run_menu (menu, nested, &auto_boot);
       if (boot_entry < 0)
@@ -869,7 +878,11 @@ show_menu (grub_menu_t menu, int nested, int autobooted)
       if (! e)
 	continue; /* Menu is empty.  */
 
-      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 ();
 
       if (auto_boot)
 	grub_menu_execute_with_fallback (menu, e, autobooted,

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"
 
@@ -158,10 +159,12 @@ 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
   if test -d /sys/firmware/efi && test -e "${linux}.efi.signed"; then
     sed "s/^/$submenu_indentation/" << EOF
 	linux	${rel_dirname}/${basename}.efi.signed root=${linux_root_device_thisversion} ro ${args}
@@ -173,13 +176,17 @@ EOF
   fi
   if test -n "${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