diff options
| -rw-r--r-- | docs/manual/configure.txt | 57 | ||||
| -rw-r--r-- | system/Config.in | 4 |
2 files changed, 32 insertions, 29 deletions
diff --git a/docs/manual/configure.txt b/docs/manual/configure.txt index dd34eef1f..44f5d244d 100644 --- a/docs/manual/configure.txt +++ b/docs/manual/configure.txt @@ -295,39 +295,42 @@ 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 - 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 - +mdev+ userspace utility on top of it. +mdev+ is a program part of - BusyBox that the kernel will call every time a device is added or - removed. Thanks to the +/etc/mdev.conf+ configuration file, +mdev+ - can be configured to for example, set specific permissions or - ownership on a device file, call a script or application whenever a - device appears or disappear, etc. Basically, it allows _userspace_ - to react on device addition and removal events. +mdev+ can for - example be used to automatically load kernel modules when devices - appear on the system. +mdev+ is also important if you have devices - that require a firmware, as it will be responsible for pushing the - firmware contents to the kernel. +mdev+ is a lightweight - implementation (with fewer features) of +udev+. For more details - about +mdev+ and the syntax of its configuration file, see + * 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 +mdev+ userspace utility on top of it. +mdev+ + is a program part of BusyBox that the kernel will call every time a + device is added or removed. Thanks to the +/etc/mdev.conf+ + configuration file, +mdev+ can be configured to for example, set + specific permissions or ownership on a device file, call a script + or application whenever a device appears or disappear, + etc. Basically, it allows _userspace_ to react on device addition + and removal events. +mdev+ can for example be used to automatically + load kernel modules when devices appear on the system. +mdev+ is + also important if you have devices that require a firmware, as it + will be responsible for pushing the firmware contents to the + kernel. +mdev+ is a lightweight implementation (with fewer + features) of +udev+. For more details 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 - 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 - device gets added or removed from the system. It is a more - heavyweight solution than +mdev+, but provides higher flexibility. - +eudev+ is a standalone version of +udev+, the original userspace - daemon used in most desktop Linux distributions, which is now part - of Systemd. For more details, see http://en.wikipedia.org/wiki/Udev. + * 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 device gets added or removed from the system. It is a + more heavyweight solution than +mdev+, but provides higher + flexibility. +eudev+ is a standalone version of +udev+, the + original userspace daemon used in most desktop Linux distributions, + which is now part of Systemd. For more details, see + http://en.wikipedia.org/wiki/Udev. 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 45170d8d0..6afe8962d 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 |