From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnout Vandecappelle Date: Wed, 9 Sep 2015 22:33:29 +0200 Subject: [Buildroot] [RFC 3/6] system: add mdev-only /dev management (without devtmpfs) In-Reply-To: <20150909132929.5c01433e@free-electrons.com> References: <1441747734-18730-1-git-send-email-luca@lucaceresoli.net> <1441747734-18730-4-git-send-email-luca@lucaceresoli.net> <20150909132929.5c01433e@free-electrons.com> Message-ID: <55F09799.6030609@mind.be> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net On 09-09-15 13:29, Thomas Petazzoni wrote: > Luca, > > On Tue, 8 Sep 2015 23:28:51 +0200, Luca Ceresoli wrote: >> There are a few reasons for an embedded Linux system not to use devtmpfs, >> but still want to have dynamic /dev management. The most notable is to use >> a kernel < 2.6.32, which have no devtmpfs support. >> >> For such corner cases, we introduce the ability to use busybox mdev for >> /dev management even without devtmpfs. >> >> First, we need the BR2_ROOTFS_STATIC_DEVICE_TABLE just like the static >> /dev management, in order to have the very basic devices such as /dev/null >> and /dev/console until mdev is enabled. > > As said in another e-mail, this is not really true: we just need a very > simple, two devices long, hard-coded device table. There is no need to > allow the user to customize it. It would in fact be potentially > misleading because the user who would add more devices in this static > device table would not see them on the target: they would be > "overridden" by the tmpfs mounted in /dev. Right! So: define BUSYBOX_DEVICES /dev/console c 666 0 0 5 1 - - - /dev/null c 666 0 0 1 3 0 0 - endef Regards, Arnout [snip] -- Arnout Vandecappelle arnout at mind be Senior Embedded Software Architect +32-16-286500 Essensium/Mind http://www.mind.be G.Geenslaan 9, 3001 Leuven, Belgium BE 872 984 063 RPR Leuven LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle GPG fingerprint: 7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF