fbcon: logo: disable logo at boot

Add logo.nologo kernel boot option to disable the logo in order to provide
more screen space for kernel messages; especially useful when debugging and
screen space is more critical.

newport_con driver changes are untested.

[akpm@linux-foundation.org: cleanups, coding-style fixes]
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 26 insertions, 6 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 760ed5776174..eb247997f679 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -911,6 +911,11 @@ and is between 256 and 4096 characters. It is defined in the file
                         n must be a power of two.  The default size
                         is set in the kernel config file.
 
+        logo.nologo     [FB] Disables display of the built-in Linux logo.
+                        This may be used to provide more screen space for
+                        kernel log messages and is useful when debugging
+                        kernel boot problems.
+
         lp=0            [LP]    Specify parallel ports to use, e.g,
         lp=port[,port...]       lp=none,parport0 (lp0 not configured, lp1 uses
         lp=reset                first parallel port). 'lp=0' disables the
diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index dda0586ab3f3..f57d7b2758b7 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -98,14 +98,19 @@ static inline void newport_init_cmap(void)
         }
 }
 
-static void newport_show_logo(void)
+static struct linux_logo *newport_show_logo(void)
 {
 #ifdef CONFIG_LOGO_SGI_CLUT224
         const struct linux_logo *logo = fb_find_logo(8);
-        const unsigned char *clut = logo->clut;
-        const unsigned char *data = logo->data;
+        const unsigned char *clut;
+        const unsigned char *data;
         unsigned long i;
 
+        if (!logo)
+                return NULL;
+        *clut = logo->clut;
+        *data = logo->data;
+
         for (i = 0; i < logo->clutsize; i++) {
                 newport_bfwait(npregs);
                 newport_cmap_setaddr(npregs, i + 0x20);
@@ -123,6 +128,8 @@ static void newport_show_logo(void)
 
         for (i = 0; i < logo->width*logo->height; i++)
                 npregs->go.hostrw0 = *data++ << 24;
+
+        return logo;
 #endif /* CONFIG_LOGO_SGI_CLUT224 */
 }
 
@@ -465,9 +472,10 @@ static int newport_switch(struct vc_data *vc)
         npregs->cset.topscan = 0x3ff;
 
         if (!logo_drawn) {
-                newport_show_logo();
-                logo_drawn = 1;
-                logo_active = 1;
+                if (newport_show_logo()) {
+                        logo_drawn = 1;
+                        logo_active = 1;
+                }
         }
 
         return 1;
diff --git a/drivers/video/logo/logo.c b/drivers/video/logo/logo.c
index 2b0f799aa8da..a9283bae7790 100644
--- a/drivers/video/logo/logo.c
+++ b/drivers/video/logo/logo.c
@@ -34,6 +34,10 @@ extern const struct linux_logo logo_superh_vga16;
 extern const struct linux_logo logo_superh_clut224;
 extern const struct linux_logo logo_m32r_clut224;
 
+static int nologo;
+module_param(nologo, bool, 0);
+MODULE_PARM_DESC(nologo, "Disables startup logo");
+
 /* logo's are marked __initdata. Use __init_refok to tell
  * modpost that it is intended that this function uses data
  * marked __initdata.
@@ -42,6 +46,9 @@ const struct linux_logo * __init_refok fb_find_logo(int depth)
 {
         const struct linux_logo *logo = NULL;
 
+        if (nologo)
+                return NULL;
+
         if (depth >= 1) {
 #ifdef CONFIG_LOGO_LINUX_MONO
                 /* Generic Linux logo */