1 files changed, 33 insertions, 18 deletions

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index ee377270beb9..fd52c48ee762 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -3,35 +3,50 @@ menu "Generic Driver Options"
 config UEVENT_HELPER_PATH
         string "path to uevent helper"
         depends on HOTPLUG
-        default "/sbin/hotplug"
+        default ""
         help
           Path to uevent helper program forked by the kernel for
           every uevent.
+          Before the switch to the netlink-based uevent source, this was
+          used to hook hotplug scripts into kernel device events. It
+          usually pointed to a shell script at /sbin/hotplug.
+          This should not be used today, because usual systems create
+          many events at bootup or device discovery in a very short time
+          frame. One forked process per event can create so many processes
+          that it creates a high system load, or on smaller systems
+          it is known to create out-of-memory situations during bootup.
 
 config DEVTMPFS
-        bool "Create a kernel maintained /dev tmpfs (EXPERIMENTAL)"
+        bool "Maintain a devtmpfs filesystem to mount at /dev"
         depends on HOTPLUG && SHMEM && TMPFS
         help
-          This creates a tmpfs filesystem, and mounts it at bootup
-          and mounts it at /dev. The kernel driver core creates device
-          nodes for all registered devices in that filesystem. All device
-          nodes are owned by root and have the default mode of 0600.
-          Userspace can add and delete the nodes as needed. This is
-          intended to simplify bootup, and make it possible to delay
-          the initial coldplug at bootup done by udev in userspace.
-          It should also provide a simpler way for rescue systems
-          to bring up a kernel with dynamic major/minor numbers.
-          Meaningful symlinks, permissions and device ownership must
-          still be handled by userspace.
-          If unsure, say N here.
+          This creates a tmpfs filesystem instance early at bootup.
+          In this filesystem, the kernel driver core maintains device
+          nodes with their default names and permissions for all
+          registered devices with an assigned major/minor number.
+          Userspace can modify the filesystem content as needed, add
+          symlinks, and apply needed permissions.
+          It provides a fully functional /dev directory, where usually
+          udev runs on top, managing permissions and adding meaningful
+          symlinks.
+          In very limited environments, it may provide a sufficient
+          functional /dev without any further help. It also allows simple
+          rescue systems, and reliably handles dynamic major/minor numbers.
 
 config DEVTMPFS_MOUNT
-        bool "Automount devtmpfs at /dev"
+        bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs"
         depends on DEVTMPFS
         help
-          This will mount devtmpfs at /dev if the kernel mounts the root
-          filesystem. It will not affect initramfs based mounting.
-          If unsure, say N here.
+          This will instruct the kernel to automatically mount the
+          devtmpfs filesystem at /dev, directly after the kernel has
+          mounted the root filesystem. The behavior can be overridden
+          with the commandline parameter: devtmpfs.mount=0|1.
+          This option does not affect initramfs based booting, here
+          the devtmpfs filesystem always needs to be mounted manually
+          after the roots is mounted.
+          With this option enabled, it allows to bring up a system in
+          rescue mode with init=/bin/sh, even when the /dev directory
+          on the rootfs is completely empty.
 
 config STANDALONE
         bool "Select only drivers that don't need compile-time external firmware" if EXPERIMENTAL