Subject: [PATCH] lz4c: shut up lz4c output

From: [email-masked] (Michal Marek)
Date: Mon, 29 Feb 2016 13:58:13 +0100

On 2016-02-29 13:40, Arnd Bergmann wrote:
> When KERNEL_LZ4 is set, we always get an output even when building
> with 'make -s':
> 
>     *** LZ4 Compression CLI , by Yann Collet (May 31 2013) ***
>     ! Generating compressed LZ4 using Legacy format (deprecated !) !
>     Using stdin for input
>     Using stdout for output
>     Compressed 11213376 bytes into 4555781 bytes ==> 40.63%
>     Done in 0.63 s ==> 16.97 MB/s
> 
> The output is not helpful in the context of building the kernel,
> so this patch hides the stdout output of the lz4 binary completely.

> -	lz4c -l -c1 stdin stdout && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
> +	lz4c -l -c1 stdin stdout && $(call size_append, $(filter-out FORCE,$^))) > $@ 2>&1 || \
>  	(rm -f $@ ; false)

Hi Arnd,

this redirection does not hide it, but rather includes it in the
compressed image file.

BTW, my copy of lz4c only displays this warning with -v.

Michal