Documentation/driver-api/device_link.rst

27 In its standard or *managed* form, a device link combines *both* dependency
57 device ``->probe`` callback or a boot-time PCI quirk.
61 ``->probe`` callback while the supplier hasn't started to probe yet:  Had the
65 non-presence.  [Note that it is valid to create a link from the consumer's
66 ``->probe`` callback while the supplier is still probing, but the consumer must
72 is added in the ``->probe`` callback of the supplier or consumer driver, it is
73 typically deleted in its ``->remove`` callback for symmetry.  That way, if the
77 to deletion.  Device links managed by the driver core are deleted automatically
87 link is added from the consumer's ``->probe`` callback:  ``DL_FLAG_RPM_ACTIVE``
93 Similarly, when the device link is added from supplier's ``->probe`` callback,
109 Driver authors should be aware that a driver presence dependency for managed
116 Moreover, managed device links cannot be deleted directly.  They are deleted
125 :c:func:`device_link_add()` may cause the PM-runtime usage counter of the
129 called twice in a row for the same consumer-supplier pair without removing the
130 link between these calls, in which case allowing the PM-runtime usage counter
132 suspended while the consumer is still PM-runtime-active and that has to be
135 it with PM-runtime disabled, between the :c:func:`device_link_add()` and
142 resources at probe time but on non-presence there is no way to know whether
156   power domain.  The MMU implements DMA address translation for the busmaster
164   The fact that both devices share the same power domain would normally
166   however these are not independent devices that happen to share a power
173   the NHI device needs to re-establish PCI tunnels to attached devices
183   of the VGA device, yet both share the same power domain and the HDA
189   A classical example is when ACPI power management methods on one device
191   I\ :sup:`2`\ C controller to be present and functional for the power
206   devices and turn off the power switch only when all of them are runtime
217 The device hierarchy, which -- as the name implies -- is a tree,
222 no device links present, the two lists are a flattened, one-dimensional
225 or OpenFirmware device tree top-down and appending devices to the lists
231 entire sub-graph below it (all children and consumers of the consumer)
256 .. kernel-doc:: include/linux/device.h