docs/devel/kconfig.rst

31   of boards or devices.  For example, by default most targets will include
44 QEMU; the default configuration that QEMU ships with should be okay in
103 **default value**: ``default <value> [if <expr>]``
105   Default values are assigned to the config symbol if no other value was
110   the default value can be added with ``if``.
112   A configuration element can have any number of default values (usually,
113   if more than one default is present, they will have different
114   conditions). If multiple default values satisfy their condition,
117 **reverse default** (weak reverse dependency): ``imply <symbol> [if <expr>]``
120   to another symbol.  However, the lower limit is only a default
131       default y if FOO
133   The next section explains where to use ``imply`` or ``default y``.
148   Subsystems always default to false (they have no ``default`` directive)
162       default y if PCI_DEVICES
167   of directives that cooperate so that a default configuration includes
174   ``select SCSI``.  Finally, devices are usually ``default y`` if and
175   only if they have at least one ``depends on``; the default could be
193   as conditions for ``default y`` directives.
196   and ``TEST_DEVICES``.  PCI devices usually have a ``default y if
197   PCI_DEVICES`` directive rather than just ``default y``.  This lets
214       default y
233   may not be started without it.  Boards default to true, but also
257 Writing and modifying default configurations
262 initialize some Kconfig variables to non-default values and provide the
267     # Default configuration for alpha-softmmu
282 the default configuration by uncommenting lines in the first group,
286 ``--without-default-devices`` option.  When this is done, everything defaults
288 ``.mak`` files.  In other words, ``default`` and ``imply`` directives
297 without default devices might not do much more than start an empty
301 ``--without-default-devices`` are considered bugs in the test code: