From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Fri, 28 Jan 2022 12:43:49 +0100
Subject: [PATCH] EFI: console: Do not set cursor until the first text output

To allow flickerfree boot the EFI console code does not call
grub_efi_set_text_mode (1) until some text is actually output.

Depending on if the output text is because of an error loading
e.g. the .cfg file; or because of showing the menu the cursor needs
to be on or off when the first text is shown.

So far the cursor was hardcoded to being on, but this is causing
drawing artifacts + slow drawing of the menu as reported here:
https://bugzilla.redhat.com/show_bug.cgi?id=1946969

Handle the cursorstate in the same way as the colorstate to fix this,
when no text has been output yet, just cache the cursorstate and
then use the last set value when the first text is output.

Fixes: 2d7c3abd871f ("efi/console: Do not set text-mode until we actually need it")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 grub-core/term/efi/console.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/grub-core/term/efi/console.c b/grub-core/term/efi/console.c
index c44b2ac318..a3622e4fe5 100644
--- a/grub-core/term/efi/console.c
+++ b/grub-core/term/efi/console.c
@@ -31,7 +31,15 @@ typedef enum {
 }
 grub_text_mode;
 
+typedef enum {
+    GRUB_CURSOR_MODE_UNDEFINED = -1,
+    GRUB_CURSOR_MODE_OFF = 0,
+    GRUB_CURSUR_MODE_ON
+}
+grub_cursor_mode;
+
 static grub_text_mode text_mode = GRUB_TEXT_MODE_UNDEFINED;
+static grub_cursor_mode cursor_mode = GRUB_CURSOR_MODE_UNDEFINED;
 static grub_term_color_state text_colorstate = GRUB_TERM_COLOR_UNDEFINED;
 
 static grub_uint32_t
@@ -119,8 +127,12 @@ grub_console_setcursor (struct grub_term_output *term __attribute__ ((unused)),
 {
   grub_efi_simple_text_output_interface_t *o;
 
-  if (grub_efi_is_finished)
-    return;
+  if (grub_efi_is_finished || text_mode != GRUB_TEXT_MODE_AVAILABLE)
+    {
+      /* Cache cursor changes before the first text-output */
+      cursor_mode = on;
+      return;
+    }
 
   o = grub_efi_system_table->con_out;
   efi_call_2 (o->enable_cursor, o, on);
@@ -143,7 +155,8 @@ grub_prepare_for_text_output (struct grub_term_output *term)
       return GRUB_ERR_BAD_DEVICE;
     }
 
-  grub_console_setcursor (term, 1);
+  if (cursor_mode != GRUB_CURSOR_MODE_UNDEFINED)
+    grub_console_setcursor (term, cursor_mode);
   if (text_colorstate != GRUB_TERM_COLOR_UNDEFINED)
     grub_console_setcolorstate (term, text_colorstate);
   text_mode = GRUB_TEXT_MODE_AVAILABLE;