18c2ecf20Sopenharmony_ci# SPDX-License-Identifier: GPL-2.0-only 28c2ecf20Sopenharmony_ciconfig SYSFS 38c2ecf20Sopenharmony_ci bool "sysfs file system support" if EXPERT 48c2ecf20Sopenharmony_ci default y 58c2ecf20Sopenharmony_ci select KERNFS 68c2ecf20Sopenharmony_ci help 78c2ecf20Sopenharmony_ci The sysfs filesystem is a virtual filesystem that the kernel uses to 88c2ecf20Sopenharmony_ci export internal kernel objects, their attributes, and their 98c2ecf20Sopenharmony_ci relationships to one another. 108c2ecf20Sopenharmony_ci 118c2ecf20Sopenharmony_ci Users can use sysfs to ascertain useful information about the running 128c2ecf20Sopenharmony_ci kernel, such as the devices the kernel has discovered on each bus and 138c2ecf20Sopenharmony_ci which driver each is bound to. sysfs can also be used to tune devices 148c2ecf20Sopenharmony_ci and other kernel subsystems. 158c2ecf20Sopenharmony_ci 168c2ecf20Sopenharmony_ci Some system agents rely on the information in sysfs to operate. 178c2ecf20Sopenharmony_ci /sbin/hotplug uses device and object attributes in sysfs to assist in 188c2ecf20Sopenharmony_ci delegating policy decisions, like persistently naming devices. 198c2ecf20Sopenharmony_ci 208c2ecf20Sopenharmony_ci sysfs is currently used by the block subsystem to mount the root 218c2ecf20Sopenharmony_ci partition. If sysfs is disabled you must specify the boot device on 228c2ecf20Sopenharmony_ci the kernel boot command line via its major and minor numbers. For 238c2ecf20Sopenharmony_ci example, "root=03:01" for /dev/hda1. 248c2ecf20Sopenharmony_ci 258c2ecf20Sopenharmony_ci Designers of embedded systems may wish to say N here to conserve space. 26