From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Wed, 9 Sep 2015 13:23:33 +0200 Subject: [Buildroot] [RFC 3/6] system: add mdev-only /dev management (without devtmpfs) In-Reply-To: <55EFFD38.5010104@mind.be> References: <1441747734-18730-1-git-send-email-luca@lucaceresoli.net> <1441747734-18730-4-git-send-email-luca@lucaceresoli.net> <55EFFD38.5010104@mind.be> Message-ID: <20150909132333.5bbaf57c@free-electrons.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Arnout, Luca, On Wed, 9 Sep 2015 11:34:48 +0200, Arnout Vandecappelle wrote: > On 08-09-15 23:28, Luca Ceresoli wrote: > > 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. > > Actually, I don't think this is a good idea: we're asking the user to configure > a static device table which is not going to be used anyway. > > I think it's better to move /dev/null and /dev/console to device_table.txt - > i.e., include them in every rootfs. It just increases the size with a few > hundred bytes, it doesn't hurt because devtmpfs is normally automounted over it > right away, and it is better for the cpio/initramfs case because you won't get > the 'Unable to open initial console' message anymore (I think). Plus, the > redirects can be removed from fs/cpio/init since they'll be automatic. > > What do the other developers think? I would prefer to keep /dev/null and /dev/console in a special device table, used only for the mdev without devtmpfs case, but not make it configurable. So, I would actually not make the option BR2_ROOTFS_STATIC_DEVICE_TABLE visible for the BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_MDEV_ONLY case, and instead force using a minimal, hard-coded, device table in this case. There is no reason whatsoever to have anything else but /dev/null and /dev/zero in the mdev without devtmpfs case. Best regards, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com