[PATCH 0/2] Add possibility to specify the number of displayed logos

[PATCH 0/2] Add possibility to specify the number of displayed logos

[Peter Rosin]

Hi!

The first patch fixes the fact that there are two items numbered "4" in
the list of fbcon options. This bug is a teenager...

The second patch extends that list with a new option that allows the
user to display any number of logos (that fits on the screen). I need it
to limit the display to only one logo instead of one for each CPU core.

Cheers,
Peter

Peter Rosin (2):
  fbdev: fix numbering of fbcon options
  fbdev: fbmem: allow overriding the number of bootup logos

 Documentation/fb/fbcon.rst       | 13 +++++++++----
 drivers/video/fbdev/core/fbcon.c |  7 +++++++
 drivers/video/fbdev/core/fbmem.c |  5 ++++-
 include/linux/fb.h               |  1 +
 4 files changed, 21 insertions(+), 5 deletions(-)

-- 
2.11.0

[PATCH 1/2] fbdev: fix numbering of fbcon options

[Peter Rosin]

Three shall be the number thou shalt count, and the number of the
counting shall be three. Four shalt thou not count...

One! Two! Five!

Fixes: efb985f6b265 ("[PATCH] fbcon: Console Rotation - Add framebuffer console documentation")
Signed-off-by: Peter Rosin <peda@axentia.se>
---
 Documentation/fb/fbcon.rst | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Documentation/fb/fbcon.rst b/Documentation/fb/fbcon.rst
index ebca41785abe..65ba40255137 100644
--- a/Documentation/fb/fbcon.rst
+++ b/Documentation/fb/fbcon.rst
@@ -127,7 +127,7 @@ C. Boot options
 	is typically located on the same video card.  Thus, the consoles that
 	are controlled by the VGA console will be garbled.
 
-4. fbcon=rotate:<n>
+5. fbcon=rotate:<n>
 
 	This option changes the orientation angle of the console display. The
 	value 'n' accepts the following:
@@ -152,21 +152,21 @@ C. Boot options
 	Actually, the underlying fb driver is totally ignorant of console
 	rotation.
 
-5. fbcon=margin:<color>
+6. fbcon=margin:<color>
 
 	This option specifies the color of the margins. The margins are the
 	leftover area at the right and the bottom of the screen that are not
 	used by text. By default, this area will be black. The 'color' value
 	is an integer number that depends on the framebuffer driver being used.
 
-6. fbcon=nodefer
+7. fbcon=nodefer
 
 	If the kernel is compiled with deferred fbcon takeover support, normally
 	the framebuffer contents, left in place by the firmware/bootloader, will
 	be preserved until there actually is some text is output to the console.
 	This option causes fbcon to bind immediately to the fbdev device.
 
-7. fbcon=logo-pos:<location>
+8. fbcon=logo-pos:<location>
 
 	The only possible 'location' is 'center' (without quotes), and when
 	given, the bootup logo is moved from the default top-left corner
-- 
2.11.0

[PATCH 2/2] fbdev: fbmem: allow overriding the number of bootup logos

[Peter Rosin]

Probably most useful if you only want one logo regardless of how many
CPU cores you have.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 Documentation/fb/fbcon.rst       | 5 +++++
 drivers/video/fbdev/core/fbcon.c | 7 +++++++
 drivers/video/fbdev/core/fbmem.c | 5 ++++-
 include/linux/fb.h               | 1 +
 4 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/Documentation/fb/fbcon.rst b/Documentation/fb/fbcon.rst
index 65ba40255137..9f0b399d8d4e 100644
--- a/Documentation/fb/fbcon.rst
+++ b/Documentation/fb/fbcon.rst
@@ -174,6 +174,11 @@ C. Boot options
 	displayed due to multiple CPUs, the collected line of logos is moved
 	as a whole.
 
+9. fbcon=logo-count:<n>
+
+	The value 'n' overrides the number of bootup logos. Zero gives the
+	default, which is the number of online cpus.
+
 C. Attaching, Detaching and Unloading
 
 Before going on to how to attach, detach and unload the framebuffer console, an
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index c9235a2f42f8..be4bc5540aad 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -536,6 +536,13 @@ static int __init fb_console_setup(char *this_opt)
 				fb_center_logo = true;
 			continue;
 		}
+
+		if (!strncmp(options, "logo-count:", 11)) {
+			options += 11;
+			if (*options)
+				fb_logo_count = simple_strtoul(options, &options, 0);
+			continue;
+		}
 	}
 	return 1;
 }
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 64dd732021d8..4c57d522b72e 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -56,6 +56,9 @@ EXPORT_SYMBOL(num_registered_fb);
 bool fb_center_logo __read_mostly;
 EXPORT_SYMBOL(fb_center_logo);
 
+unsigned int fb_logo_count __read_mostly;
+EXPORT_SYMBOL(fb_logo_count);
+
 static struct fb_info *get_fb_info(unsigned int idx)
 {
 	struct fb_info *fb_info;
@@ -689,7 +692,7 @@ int fb_show_logo(struct fb_info *info, int rotate)
 	int y;
 
 	y = fb_show_logo_line(info, rotate, fb_logo.logo, 0,
-			      num_online_cpus());
+			      fb_logo_count ?: num_online_cpus());
 	y = fb_show_extra_logos(info, y, rotate);
 
 	return y;
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 303771264644..5f2b05406262 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -630,6 +630,7 @@ extern int fb_new_modelist(struct fb_info *info);
 extern struct fb_info *registered_fb[FB_MAX];
 extern int num_registered_fb;
 extern bool fb_center_logo;
+extern unsigned int fb_logo_count;
 extern struct class *fb_class;
 
 #define for_each_registered_fb(i)		\
-- 
2.11.0

Re: [PATCH 2/2] fbdev: fbmem: allow overriding the number of bootup logos

[Matthew Wilcox]

On Fri, Aug 23, 2019 at 08:47:47AM +0000, Peter Rosin wrote:
> +++ b/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -56,6 +56,9 @@ EXPORT_SYMBOL(num_registered_fb);
>  bool fb_center_logo __read_mostly;
>  EXPORT_SYMBOL(fb_center_logo);
>  
> +unsigned int fb_logo_count __read_mostly;
> +EXPORT_SYMBOL(fb_logo_count);

Why does this symbol need to be exported?  As I read the Makefile, fbcon
and fbmem are combined into the same module, so while the symbol needs
to be non-static, it doesn't need to be exported to other modules.

Re: [PATCH 2/2] fbdev: fbmem: allow overriding the number of bootup logos

[Peter Rosin]

On 2019-08-24 17:34, Matthew Wilcox wrote:
> On Fri, Aug 23, 2019 at 08:47:47AM +0000, Peter Rosin wrote:
>> +++ b/drivers/video/fbdev/core/fbcon.c
>> +++ b/drivers/video/fbdev/core/fbmem.c
>> @@ -56,6 +56,9 @@ EXPORT_SYMBOL(num_registered_fb);
>>  bool fb_center_logo __read_mostly;
>>  EXPORT_SYMBOL(fb_center_logo);
>>  
>> +unsigned int fb_logo_count __read_mostly;
>> +EXPORT_SYMBOL(fb_logo_count);
> 
> Why does this symbol need to be exported?  As I read the Makefile, fbcon
> and fbmem are combined into the same module, so while the symbol needs
> to be non-static, it doesn't need to be exported to other modules.

I guess you are right. I'll send a v2 tomorrow with an added patch to
unexport the fb_center_logo variable while at it...

Thanks for the feedback.

Cheers,
Peter