1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index bcf59b28a14f..d27fa91e5886 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -95,6 +95,7 @@ static unsigned long vgacon_uni_pagedir[2];
 /* Description of the hardware situation */
 static unsigned long    vga_vram_base;          /* Base of video memory */
 static unsigned long    vga_vram_end;           /* End of video memory */
+static int              vga_vram_size;          /* Size of video memory */
 static u16              vga_video_port_reg;     /* Video register select port */
 static u16              vga_video_port_val;     /* Video register value port */
 static unsigned int     vga_video_num_columns;  /* Number of text columns */
@@ -288,6 +289,7 @@ static const char __init *vgacon_startup(void)
 
         vga_vram_base = VGA_MAP_MEM(vga_vram_base);
         vga_vram_end = VGA_MAP_MEM(vga_vram_end);
+        vga_vram_size = vga_vram_end - vga_vram_base;
 
         /*
          *      Find out if there is a graphics card present.
@@ -504,9 +506,13 @@ static int vgacon_switch(struct vc_data *c)
          */
         vga_video_num_columns = c->vc_cols;
         vga_video_num_lines = c->vc_rows;
+
+        /* We can only copy out the size of the video buffer here,
+         * otherwise we get into VGA BIOS */
+
         if (!vga_is_gfx)
                 scr_memcpyw((u16 *) c->vc_origin, (u16 *) c->vc_screenbuf,
-                            c->vc_screenbuf_size);
+                            c->vc_screenbuf_size > vga_vram_size ? vga_vram_size : c->vc_screenbuf_size);
         return 0;               /* Redrawing not needed */
 }
 
@@ -961,7 +967,6 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines)
         if (!lines)             /* Turn scrollback off */
                 c->vc_visible_origin = c->vc_origin;
         else {
-                int vram_size = vga_vram_end - vga_vram_base;
                 int margin = c->vc_size_row * 4;
                 int ul, we, p, st;
 
@@ -971,7 +976,7 @@ static int vgacon_scrolldelta(struct vc_data *c, int lines)
                         we = vga_rolled_over + c->vc_size_row;
                 } else {
                         ul = 0;
-                        we = vram_size;
+                        we = vga_vram_size;
                 }
                 p = (c->vc_visible_origin - vga_vram_base - ul + we) % we +
                     lines * c->vc_size_row;
@@ -1012,9 +1017,13 @@ static void vgacon_save_screen(struct vc_data *c)
                 c->vc_x = ORIG_X;
                 c->vc_y = ORIG_Y;
         }
+
+        /* We can't copy in more then the size of the video buffer,
+         * or we'll be copying in VGA BIOS */
+
         if (!vga_is_gfx)
                 scr_memcpyw((u16 *) c->vc_screenbuf, (u16 *) c->vc_origin,
-                            c->vc_screenbuf_size);
+                            c->vc_screenbuf_size > vga_vram_size ? vga_vram_size : c->vc_screenbuf_size);
 }
 
 static int vgacon_scroll(struct vc_data *c, int t, int b, int dir,