Root/drivers/base/Kconfig

1menu "Generic Driver Options"
2
3config UEVENT_HELPER_PATH
4    string "path to uevent helper"
5    depends on HOTPLUG
6    default ""
7    help
8      Path to uevent helper program forked by the kernel for
9      every uevent.
10      Before the switch to the netlink-based uevent source, this was
11      used to hook hotplug scripts into kernel device events. It
12      usually pointed to a shell script at /sbin/hotplug.
13      This should not be used today, because usual systems create
14      many events at bootup or device discovery in a very short time
15      frame. One forked process per event can create so many processes
16      that it creates a high system load, or on smaller systems
17      it is known to create out-of-memory situations during bootup.
18
19config DEVTMPFS
20    bool "Maintain a devtmpfs filesystem to mount at /dev"
21    depends on HOTPLUG && SHMEM && TMPFS
22    help
23      This creates a tmpfs filesystem instance early at bootup.
24      In this filesystem, the kernel driver core maintains device
25      nodes with their default names and permissions for all
26      registered devices with an assigned major/minor number.
27      Userspace can modify the filesystem content as needed, add
28      symlinks, and apply needed permissions.
29      It provides a fully functional /dev directory, where usually
30      udev runs on top, managing permissions and adding meaningful
31      symlinks.
32      In very limited environments, it may provide a sufficient
33      functional /dev without any further help. It also allows simple
34      rescue systems, and reliably handles dynamic major/minor numbers.
35
36config DEVTMPFS_MOUNT
37    bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs"
38    depends on DEVTMPFS
39    help
40      This will instruct the kernel to automatically mount the
41      devtmpfs filesystem at /dev, directly after the kernel has
42      mounted the root filesystem. The behavior can be overridden
43      with the commandline parameter: devtmpfs.mount=0|1.
44      This option does not affect initramfs based booting, here
45      the devtmpfs filesystem always needs to be mounted manually
46      after the roots is mounted.
47      With this option enabled, it allows to bring up a system in
48      rescue mode with init=/bin/sh, even when the /dev directory
49      on the rootfs is completely empty.
50
51config STANDALONE
52    bool "Select only drivers that don't need compile-time external firmware" if EXPERIMENTAL
53    default y
54    help
55      Select this option if you don't have magic firmware for drivers that
56      need it.
57
58      If unsure, say Y.
59
60config PREVENT_FIRMWARE_BUILD
61    bool "Prevent firmware from being built"
62    default y
63    help
64      Say yes to avoid building firmware. Firmware is usually shipped
65      with the driver, and only when updating the firmware a rebuild
66      should be made.
67      If unsure say Y here.
68
69config FW_LOADER
70    tristate "Userspace firmware loading support" if EMBEDDED
71    depends on HOTPLUG
72    default y
73    ---help---
74      This option is provided for the case where no in-kernel-tree modules
75      require userspace firmware loading support, but a module built outside
76      the kernel tree does.
77
78config FIRMWARE_IN_KERNEL
79    bool "Include in-kernel firmware blobs in kernel binary"
80    depends on FW_LOADER
81    default y
82    help
83      The kernel source tree includes a number of firmware 'blobs'
84      which are used by various drivers. The recommended way to
85      use these is to run "make firmware_install" and to copy the
86      resulting binary files created in usr/lib/firmware directory
87      of the kernel tree to the /lib/firmware on your system so
88      that they can be loaded by userspace helpers on request.
89
90      Enabling this option will build each required firmware blob
91      into the kernel directly, where request_firmware() will find
92      them without having to call out to userspace. This may be
93      useful if your root file system requires a device which uses
94      such firmware, and do not wish to use an initrd.
95
96      This single option controls the inclusion of firmware for
97      every driver which uses request_firmware() and ships its
98      firmware in the kernel source tree, to avoid a proliferation
99      of 'Include firmware for xxx device' options.
100
101      Say 'N' and let firmware be loaded from userspace.
102
103config EXTRA_FIRMWARE
104    string "External firmware blobs to build into the kernel binary"
105    depends on FW_LOADER
106    help
107      This option allows firmware to be built into the kernel, for the
108      cases where the user either cannot or doesn't want to provide it from
109      userspace at runtime (for example, when the firmware in question is
110      required for accessing the boot device, and the user doesn't want to
111      use an initrd).
112
113      This option is a string, and takes the (space-separated) names of the
114      firmware files -- the same names which appear in MODULE_FIRMWARE()
115      and request_firmware() in the source. These files should exist under
116      the directory specified by the EXTRA_FIRMWARE_DIR option, which is
117      by default the firmware/ subdirectory of the kernel source tree.
118
119      So, for example, you might set CONFIG_EXTRA_FIRMWARE="usb8388.bin",
120      copy the usb8388.bin file into the firmware/ directory, and build the
121      kernel. Then any request_firmware("usb8388.bin") will be
122      satisfied internally without needing to call out to userspace.
123
124      WARNING: If you include additional firmware files into your binary
125      kernel image which are not available under the terms of the GPL,
126      then it may be a violation of the GPL to distribute the resulting
127      image -- since it combines both GPL and non-GPL work. You should
128      consult a lawyer of your own before distributing such an image.
129
130config EXTRA_FIRMWARE_DIR
131    string "Firmware blobs root directory"
132    depends on EXTRA_FIRMWARE != ""
133    default "firmware"
134    help
135      This option controls the directory in which the kernel build system
136      looks for the firmware files listed in the EXTRA_FIRMWARE option.
137      The default is the firmware/ directory in the kernel source tree,
138      but by changing this option you can point it elsewhere, such as
139      the /lib/firmware/ directory or another separate directory
140      containing firmware files.
141
142config DEBUG_DRIVER
143    bool "Driver Core verbose debug messages"
144    depends on DEBUG_KERNEL
145    help
146      Say Y here if you want the Driver core to produce a bunch of
147      debug messages to the system log. Select this if you are having a
148      problem with the driver core and want to see more of what is
149      going on.
150
151      If you are unsure about this, say N here.
152
153config DEBUG_DEVRES
154    bool "Managed device resources verbose debug messages"
155    depends on DEBUG_KERNEL
156    help
157      This option enables kernel parameter devres.log. If set to
158      non-zero, devres debug messages are printed. Select this if
159      you are having a problem with devres or want to debug
160      resource management for a managed device. devres.log can be
161      switched on and off from sysfs node.
162
163      If you are unsure about this, Say N here.
164
165config SYS_HYPERVISOR
166    bool
167    default n
168
169endmenu
170

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