[PATCH v3] fbcon: Silence fbcon logo on 'quiet' boots

[Prarit Bhargava]

On text-based systems the 'quiet' boot option will show printk levels
higher than CONSOLE_LOGLEVEL_QUIET.  The displaying of the Tux logo
during boot can cause some consoles to lose display data and as a result
confuse the end user.

Do not display the Tux logo on systems that are in 'quiet' boot.

v2: It helps to commit all my changes before sending them.  Remove extra
bracket.
v3: buildbot error fix: fbcon can be built as part of a module so export console_printk

Signed-off-by: Prarit Bhargava <prarit at redhat.com>
Cc: Hans de Goede <hdegoede at redhat.com>
Cc: Marko Myllynen <myllynen at redhat.com>
Cc: Steven Rostedt (VMware) <rostedt at goodmis.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
Cc: Kees Cook <keescook at chromium.org>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Thierry Reding <treding at nvidia.com>
Cc: Yisheng Xie <ysxie at foxmail.com>
Cc: dri-devel at lists.freedesktop.org
---
 drivers/video/fbdev/core/fbcon.c | 13 ++++++++-----
 kernel/printk/printk.c           |  1 +
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 8958ccc8b1ac..08e092eaf45c 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -649,11 +649,14 @@ static void fbcon_prepare_logo(struct vc_data *vc, struct fb_info *info,
 		kfree(save);
 	}
 
+	if (logo_shown == FBCON_LOGO_DONTSHOW)
+		return;
+
 	if (logo_lines > vc->vc_bottom) {
 		logo_shown = FBCON_LOGO_CANSHOW;
 		printk(KERN_INFO
 		       "fbcon_init: disable boot-logo (boot-logo bigger than screen).\n");
-	} else if (logo_shown != FBCON_LOGO_DONTSHOW) {
+	} else {
 		logo_shown = FBCON_LOGO_DRAW;
 		vc->vc_top = logo_lines;
 	}
@@ -1051,7 +1054,7 @@ static void fbcon_init(struct vc_data *vc, int init)
 	struct vc_data **default_mode = vc->vc_display_fg;
 	struct vc_data *svc = *default_mode;
 	struct display *t, *p = &fb_display[vc->vc_num];
-	int logo = 1, new_rows, new_cols, rows, cols, charcnt = 256;
+	int new_rows, new_cols, rows, cols, charcnt = 256;
 	int cap, ret;
 
 	if (info_idx == -1 || info == NULL)
@@ -1059,9 +1062,9 @@ static void fbcon_init(struct vc_data *vc, int init)
 
 	cap = info->flags;
 
-	if (vc != svc || logo_shown == FBCON_LOGO_DONTSHOW ||
+	if (vc != svc || console_loglevel <= CONSOLE_LOGLEVEL_QUIET ||
 	    (info->fix.type == FB_TYPE_TEXT))
-		logo = 0;
+		logo_shown = FBCON_LOGO_DONTSHOW;
 
 	if (var_to_display(p, &info->var, info))
 		return;
@@ -1176,7 +1179,7 @@ static void fbcon_init(struct vc_data *vc, int init)
 	} else
 		vc_resize(vc, new_cols, new_rows);
 
-	if (logo)
+	if (logo_shown != FBCON_LOGO_DONTSHOW)
 		fbcon_prepare_logo(vc, info, cols, rows, new_cols, new_rows);
 
 	if (vc == svc && softback_buf)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index b77150ad1965..391e390feac9 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -66,6 +66,7 @@ int console_printk[4] = {
 	CONSOLE_LOGLEVEL_MIN,		/* minimum_console_loglevel */
 	CONSOLE_LOGLEVEL_DEFAULT,	/* default_console_loglevel */
 };
+EXPORT_SYMBOL(console_printk);
 
 atomic_t ignore_console_lock_warning __read_mostly = ATOMIC_INIT(0);
 EXPORT_SYMBOL(ignore_console_lock_warning);
-- 
2.14.5