tty: vt: initialize softcursor_original correctly

add_softcursor() stores the contents of the text buffer position in this
variable before drawing the softcursor, whereas hide_softcursor() writes
the value back. A value of -1 means that no cursor has been drawn and
therefore no character is to be restored. softcursor_original, however,
is only implicitly initialized with 0. Therefore, when hide_softcursor
is called for the first time (console_init -> con_init -> redraw_screen
-> hide_cursor), it wrongly writes 0x0000 in the top left corner of
the text buffer. Normally, this is just as black as the rest of the
screen (vc_video_erase_char) and can't be seen, but it appears as a
black cursor rectangle on non-black backgrounds e.g. with boot option
"vt.global_cursor_default=0 vt.color=0xf0". softcursor_original needs
to be initialized with -1.

Signed-off-by: Melchior FRANZ <mfranz@aon.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index bd51bdd0a7bf2536617b1a27e3c846105c31a821..3e3c7575e92d0eaf3363bb5c3869cc139163073e 100644 (file)
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -568,7 +568,7 @@ static void delete_char(struct vc_data *vc, unsigned int nr)
                        vc->vc_cols - vc->vc_x);
 }
 
-static int softcursor_original;
+static int softcursor_original = -1;
 
 static void add_softcursor(struct vc_data *vc)
 {