From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luca Ceresoli Date: Tue, 8 Sep 2015 23:28:50 +0200 Subject: [Buildroot] [RFC 2/6] system: clarify /dev management using devtmpfs + {mdev, eudev} In-Reply-To: <1441747734-18730-1-git-send-email-luca@lucaceresoli.net> References: <1441747734-18730-1-git-send-email-luca@lucaceresoli.net> Message-ID: <1441747734-18730-3-git-send-email-luca@lucaceresoli.net> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net We're going to introduce /dev management with mdev only (no devtmpfs), which will be called "Dynamic using mdev only". In preparation to that addition, clarify the current /dev managements systems which use devtmpfs with an additional tool. Otherwise "Dynamic using mdev" and "Dynamic using mdev only" wight look quite undistinguishable to mortals... Signed-off-by: Luca Ceresoli --- docs/manual/configure.txt | 7 ++++--- system/Config.in | 4 ++-- 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/docs/manual/configure.txt b/docs/manual/configure.txt index dd34eef..997be2b 100644 --- a/docs/manual/configure.txt +++ b/docs/manual/configure.txt @@ -295,7 +295,7 @@ different solutions to handle the +/dev+ directory : responsibility to enable those two options (if you fail to do so, your Buildroot system will not boot). - * The third solution is *Dynamic using mdev*. This method also relies + * The third solution is *Dynamic using devtmpfs + mdev*. This method also relies on the _devtmpfs_ virtual filesystem detailed above (so the requirement to have +CONFIG_DEVTMPFS+ and +CONFIG_DEVTMPFS_MOUNT+ enabled in the kernel configuration still apply), but adds the @@ -314,7 +314,7 @@ different solutions to handle the +/dev+ directory : about +mdev+ and the syntax of its configuration file, see http://git.busybox.net/busybox/tree/docs/mdev.txt. - * The fourth solution is *Dynamic using eudev*. This method also + * The fourth solution is *Dynamic using devtmpfs + eudev*. This method also relies on the _devtmpfs_ virtual filesystem detailed above, but adds the +eudev+ userspace daemon on top of it. +eudev+ is a daemon that runs in the background, and gets called by the kernel when a @@ -327,7 +327,8 @@ different solutions to handle the +/dev+ directory : The Buildroot developers recommendation is to start with the *Dynamic using devtmpfs only* solution, until you have the need for userspace to be notified when devices are added/removed, or if firmwares are -needed, in which case *Dynamic using mdev* is usually a good solution. +needed, in which case *Dynamic using devtmpfs + mdev* is usually a +good solution. Note that if +systemd+ is chosen as init system, /dev management will be performed by the +udev+ program provided by +systemd+. diff --git a/system/Config.in b/system/Config.in index fad829d..5bf5048 100644 --- a/system/Config.in +++ b/system/Config.in @@ -110,11 +110,11 @@ config BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_DEVTMPFS bool "Dynamic using devtmpfs only" config BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_MDEV - bool "Dynamic using mdev" + bool "Dynamic using devtmpfs + mdev" select BR2_PACKAGE_BUSYBOX config BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV - bool "Dynamic using eudev" + bool "Dynamic using devtmpfs + eudev" depends on BR2_USE_WCHAR depends on !BR2_STATIC_LIBS depends on BR2_USE_MMU # eudev -- 1.9.1