From: Bill Burns <bburns@redhat.com>
Date: Wed, 17 Dec 2008 08:02:53 -0500
Subject: [xen] clear screen to make LUKS passphrase visible
Message-id: 20081217130251.4307.67550.sendpatchset@localhost.localdomain
O-Subject: [RHEL5.4 PATCH 2/2] Xen patch to clear screen to make LUKS passphrase visible
Bugzilla: 475986

Fixes bz 475986

>From the following two upstream changesets, clear the
console screen of the Hypervisor messages to avoid
unreadable dom0 kernel or user output.

changeset: vga: Clear the screen when relinquishing VGA to dom0.
changeset 18872: 	5e066dc410ac
parent 18871:	b44e244d7bb9
child 18873:	eed39afde7dd
author: 	Keir Fraser <keir.fraser@citrix.com>
date: 	Fri Dec 05 11:37:20 2008 +0000 (6 days ago)
files: 	xen/drivers/video/vesa.c xen/drivers/video/vga.c
description: 	vga: Clear the screen when relinquishing VGA to dom0.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

changeset: vga: Fix screen clear at end of Xen bootstrap.
changeset 18890: 	5535efd8e011
parent 18889:	cd8c7d963af5
child 18891:	6595393a3d28
author: 	Keir Fraser <keir.fraser@citrix.com>
date: 	Tue Dec 09 13:23:15 2008 +0000 (2 days ago)
files: 	xen/drivers/video/vga.c
description: 	vga: Fix screen clear at end of Xen bootstrap.
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

diff --git a/drivers/video/vesa.c b/drivers/video/vesa.c
index 8f5b5c6..bb82647 100644
--- a/drivers/video/vesa.c
+++ b/drivers/video/vesa.c
@@ -146,10 +146,20 @@ void __init vesa_init(void)
     xfree(text_buf);
 }
 
-void __init vesa_endboot(void)
+void __init vesa_endboot(bool_t keep)
 {
-    xpos = 0;
-    vga_puts = vesa_scroll_puts;
+    if ( keep )
+    {
+        xpos = 0;
+        vga_puts = vesa_scroll_puts;
+    }
+    else
+    {
+        unsigned int i, bpp = (vlfb_info.bits_per_pixel + 7) >> 3;
+        for ( i = 0; i < vlfb_info.height; i++ )
+            memset(lfb + i * vlfb_info.bytes_per_line, 0,
+                   vlfb_info.width * bpp);
+    }
 }
 
 #if defined(CONFIG_X86)
diff --git a/drivers/video/vga.c b/drivers/video/vga.c
index ef21178..7595909 100644
--- a/drivers/video/vga.c
+++ b/drivers/video/vga.c
@@ -57,10 +57,10 @@ static unsigned int columns, lines;
 
 #ifdef CONFIG_X86_64
 void vesa_early_init(void);
-void vesa_endboot(void);
+void vesa_endboot(bool_t keep);
 #else
 #define vesa_early_init() ((void)0)
-#define vesa_endboot()    ((void)0)
+#define vesa_endboot(x)   ((void)0)
 #endif
 
 void __init vga_init(void)
@@ -99,16 +99,27 @@ void __init vga_init(void)
 
 void __init vga_endboot(void)
 {
-    if ( vga_puts == vga_noop_puts )
+    if ( !vga_console_info.video_type )
         return;
 
     printk("Xen is %s VGA console.\n",
            vgacon_keep ? "keeping" : "relinquishing");
 
-    vesa_endboot();
-
     if ( !vgacon_keep )
         vga_puts = vga_noop_puts;
+
+    switch ( vga_console_info.video_type )
+    {
+    case XEN_VGATYPE_TEXT_MODE_3:
+        if ( !vgacon_keep )
+            memset(video, 0, columns * lines * 2);
+        break;
+    case XEN_VGATYPE_VESA_LFB:
+        vesa_endboot(vgacon_keep);
+        break;
+    default:
+        BUG();
+    }
 }
 
 static void vga_text_puts(const char *s)