[-mm patch] x86: start early_printk at sensible screen row

[-mm patch] x86: start early_printk at sensible screen row

[Chuck Ebbert]

Use boot info to start early_printk() at the proper row on VGA console.

Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>

--- 2.6.16-rc4-mm2-64.orig/arch/x86_64/kernel/early_printk.c
+++ 2.6.16-rc4-mm2-64/arch/x86_64/kernel/early_printk.c
@@ -244,7 +244,7 @@ int __init setup_early_printk(char *opt)
 	           && SCREEN_INFO.orig_video_isVGA == 1) {
 		max_xpos = SCREEN_INFO.orig_video_cols;
 		max_ypos = SCREEN_INFO.orig_video_lines;
-		current_ypos = max_ypos;
+		current_ypos = SCREEN_INFO.orig_y;
 		early_console = &early_vga_console; 
  	} else if (!strncmp(buf, "simnow", 6)) {
  		simnow_init(buf + 6);
-- 
Chuck
"Equations are the Devil's sentences."  --Stephen Colbert

Re: [-mm patch] x86: start early_printk at sensible screen row

[Andrew Morton]

Chuck Ebbert <76306.1226@compuserve.com> wrote:
>
> Use boot info to start early_printk() at the proper row on VGA console.
> 

Define "proper".

> 
> --- 2.6.16-rc4-mm2-64.orig/arch/x86_64/kernel/early_printk.c
> +++ 2.6.16-rc4-mm2-64/arch/x86_64/kernel/early_printk.c
> @@ -244,7 +244,7 @@ int __init setup_early_printk(char *opt)
>  	           && SCREEN_INFO.orig_video_isVGA == 1) {
>  		max_xpos = SCREEN_INFO.orig_video_cols;
>  		max_ypos = SCREEN_INFO.orig_video_lines;
> -		current_ypos = max_ypos;
> +		current_ypos = SCREEN_INFO.orig_y;
>  		early_console = &early_vga_console; 
>   	} else if (!strncmp(buf, "simnow", 6)) {
>   		simnow_init(buf + 6);

Is that the place at which the boot loader left the cursor?

Re: [-mm patch] x86: start early_printk at sensible screen row

[Chuck Ebbert]

In-Reply-To: <20060225001533.3b06bbe0.akpm@osdl.org>

On Sat, 25 Feb 2006 at 00:15:33 -0800, Andrew Morton wrote:

> >
> > Use boot info to start early_printk() at the proper row on VGA console.
> > 
> 
> Define "proper".
> 
> > 
> > -           current_ypos = max_ypos;
> > +           current_ypos = SCREEN_INFO.orig_y;
> 
> Is that the place at which the boot loader left the cursor?

Yes, that's what I should have said instead of "proper".

So far I can't break it; after booting with "vga=ask" and doing some
things at the prompt, the kernel output still starts at the right place.

But the emergency fallback early_printk still starts at a fixed place
and the x86_64 'direct mapping' message will screw things up when there's
no earlyprintk boot parameter.

-- 
Chuck
"Equations are the Devil's sentences."  --Stephen Colbert