How to disable message "Uncompressing linux..." on kernel start?

Commit Message

Felipe Balbi Sept. 18, 2012, 8:49 a.m. UTC

Hi,

On Tue, Sep 18, 2012 at 08:39:53AM +0200, Maximilian Schwerin wrote:
> I have been convinced that my patch for disabling the message
> "Uncompressing linux..." on kernel start was not all that good an idea.
> As the problem still remains an issue for me and I'd like to find a fix
> for everyone I'd like to ask for pointers where or how to fix this.
> 
> To sum up my problem: I'm using the primary serial port on an OMAP3 as a
> debug console for development. In production we set the u-boot silent
> option which disables all kernel logging to this serial port. The only
> kernel message that remains is "Uncompressing linux..." at the very
> beginning. As we connect an external device via this port in production
> environments this is not acceptable.

I don't think that would be an acceptable patch upstream, but you can
hold a local patch to remove that print from your own kernel. I'd still
try to get the production environment to ignore that "Uncompressing
Linux..." string, otherwise you will have to keep patching the kernel
for every release you try to use. Anyway, this should do:

Comments

Maximilian Schwerin Sept. 18, 2012, 9:13 a.m. UTC | #1

> -----Ursprüngliche Nachricht-----
> Von: Felipe Balbi [mailto:[e-mail]] 
> Gesendet: Dienstag, 18. September 2012 10:50
> An: Maximilian Schwerin
> Cc: [e-mail]
> Betreff: Re: How to disable message "Uncompressing linux..." 
> on kernel start? (PGP: Plain, Unable to verify signature)
> 
> Hi,
> 
> On Tue, Sep 18, 2012 at 08:39:53AM +0200, Maximilian Schwerin wrote:
> > I have been convinced that my patch for disabling the message
> > "Uncompressing linux..." on kernel start was not all that 
> good an idea.
> > As the problem still remains an issue for me and I'd like 
> to find a fix
> > for everyone I'd like to ask for pointers where or how to fix this.
> > 
> > To sum up my problem: I'm using the primary serial port on 
> an OMAP3 as a
> > debug console for development. In production we set the 
> u-boot silent
> > option which disables all kernel logging to this serial 
> port. The only
> > kernel message that remains is "Uncompressing linux..." at the very
> > beginning. As we connect an external device via this port 
> in production
> > environments this is not acceptable.
> 
> I don't think that would be an acceptable patch upstream, but you can
> hold a local patch to remove that print from your own kernel. 
> I'd still
> try to get the production environment to ignore that "Uncompressing
> Linux..." string, otherwise you will have to keep patching the kernel
> for every release you try to use. Anyway, this should do:
> 
> diff --git a/arch/arm/boot/compressed/misc.c 
> b/arch/arm/boot/compressed/misc.c
> index 8e2a8fc..e7c8ff3 100644
> --- a/arch/arm/boot/compressed/misc.c
> +++ b/arch/arm/boot/compressed/misc.c
> @@ -144,11 +144,8 @@ decompress_kernel(unsigned long 
> output_start, unsigned long free_mem_ptr_p,
>  
>  	arch_decomp_setup();
>  
> -	putstr("Uncompressing Linux...");
>  	ret = do_decompress(input_data, input_data_end - input_data,
>  			    output_data, error);
>  	if (ret)
>  		error("decompressor returned an error");
> -	else
> -		putstr(" done, booting the kernel.\n");
>  }
> 
> -- 
> balbi
> 

This is more or less what I proposed in my patch (see http://www.spinics.net/lists/arm-kernel/msg195787.html) and what I have been doing up to now.

Cheers, m.

Patch

diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c
index 8e2a8fc..e7c8ff3 100644
--- a/arch/arm/boot/compressed/misc.c
+++ b/arch/arm/boot/compressed/misc.c
@@ -144,11 +144,8 @@  decompress_kernel(unsigned long output_start, unsigned long free_mem_ptr_p,
 
 	arch_decomp_setup();
 
-	putstr("Uncompressing Linux...");
 	ret = do_decompress(input_data, input_data_end - input_data,
 			    output_data, error);
 	if (ret)
 		error("decompressor returned an error");
-	else
-		putstr(" done, booting the kernel.\n");
 }