From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lasse Collin Subject: Re: [PATCH 2/2] Squashfs: Add XZ compression configuration option Date: Fri, 10 Dec 2010 12:37:23 +0200 Message-ID: <201012101237.23379.lasse.collin@tukaani.org> References: <4D007315.1090704@lougher.demon.co.uk> <201012091109.32084.lasse.collin@tukaani.org> <4D01D70A.5050508@lougher.demon.co.uk> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4D01D70A.5050508@lougher.demon.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: Text/Plain; charset="us-ascii" To: Phillip Lougher Cc: Linux Kernel Development , linux-fsdevel@vger.kernel.org, Linux Embedded Maillist On 2010-12-10 Phillip Lougher wrote: > Lasse Collin wrote: > > On 2010-12-09 Phillip Lougher wrote: > >> +config SQUASHFS_XZ > >> + bool "Include support for XZ compressed file systems" > >> + depends on SQUASHFS > >> + default n > >> + select XZ_DEC > > > > Should "select XZ_DEC" be replaced with "depends on XZ_DEC"? XZ_DEC > > requires CRC32, so if "select XZ_DEC" is used, there needs to be > > also "select CRC32". > > XZ_DEC selects CRC32, kbuild handles these nested selects quite > happily, so if something selects XZ_DEC it knows it has to also > select CRC32. OK, I had misunderstood the notice about "select" and dependencies in Documentation/kbuild/kconfig-language.txt. > Depends on has quite different semantics to selects. If SQUASHFS_XZ > was made to depend on XZ_DEC then the option simply won't appear > unless the user knew to select XZ_DEC first (as it's default n). > This would prove extremely confusing, and probably lead to most > people thinking Squashfs didn't have XZ support, which is somewhat > undesirable. Good point. I always keep the inactive options visible in xconfig so I missed this. I will need to update my XZ boot-time support patch to use "select" instead of "depends on" too. Thanks! -- Lasse Collin | IRC: Larhzu @ IRCnet & Freenode