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Merge tag 'driver-core-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH: "Here is the "big" set of changes to the driver core, and some drivers using the changes, for 5.9-rc1. "Biggest" thing in here is the device link exposure in sysfs, to help to tame the madness that is SoC device tree representations and driver interactions with it. Other stuff in here that is interesting is: - device probe log helper so that drivers can report problems in a unified way easier. - devres functions added - DEVICE_ATTR_ADMIN_* macro added to make it harder to write incorrect sysfs file permissions - documentation cleanups - ability for debugfs to be present in the kernel, yet not exposed to userspace. Needed for systems that want it enabled, but do not trust users, so they can still use some kernel functions that were otherwise disabled. - other minor fixes and cleanups The patches outside of drivers/base/ all have acks from the respective subsystem maintainers to go through this tree instead of theirs. All of these have been in linux-next with no reported issues" * tag 'driver-core-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (39 commits) drm/bridge: lvds-codec: simplify error handling drm/bridge/sii8620: fix resource acquisition error handling driver core: add deferring probe reason to devices_deferred property driver core: add device probe log helper driver core: Avoid binding drivers to dead devices Revert "test_firmware: Test platform fw loading on non-EFI systems" firmware_loader: EFI firmware loader must handle pre-allocated buffer selftest/firmware: Add selftest timeout in settings test_firmware: Test platform fw loading on non-EFI systems driver core: Change delimiter in devlink device's name to "--" debugfs: Add access restriction option tracefs: Remove unnecessary debug_fs checks. driver core: Fix probe_count imbalance in really_probe() kobject: remove unused KOBJ_MAX action driver core: Fix sleeping in invalid context during device link deletion driver core: Add waiting_for_supplier sysfs file for devices driver core: Add state_synced sysfs file for devices that support it driver core: Expose device link details in sysfs driver core: Drop mention of obsolete bus rwsem from kernel-doc debugfs: file: Remove unnecessary cast in kfree() ...
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‎Documentation/ABI/testing/sysfs-bus-platform

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devices to opt-out of driver binding using a driver_override
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name such as "none". Only a single driver may be specified in
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the override, there is no support for parsing delimiters.
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What: /sys/bus/platform/devices/.../numa_node
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Date: June 2020
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Contact: Barry Song <[email protected]>
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Description:
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This file contains the NUMA node to which the platform device
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is attached. It won't be visible if the node is unknown. The
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value comes from an ACPI _PXM method or a similar firmware
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source. Initial users for this file would be devices like
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arm smmu which are populated by arm64 acpi_iort.

‎Documentation/ABI/testing/sysfs-class-devlink

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What: /sys/class/devlink/.../
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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Provide a place in sysfs for the device link objects in the
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kernel at any given time. The name of a device link directory,
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denoted as ... above, is of the form <supplier>--<consumer>
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where <supplier> is the supplier device name and <consumer> is
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the consumer device name.
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What: /sys/class/devlink/.../auto_remove_on
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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This file indicates if the device link will ever be
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automatically removed by the driver core when the consumer and
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supplier devices themselves are still present.
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This will be one of the following strings:
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'consumer unbind'
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'supplier unbind'
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'never'
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'consumer unbind' means the device link will be removed when
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the consumer's driver is unbound from the consumer device.
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'supplier unbind' means the device link will be removed when
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the supplier's driver is unbound from the supplier device.
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'never' means the device link will not be automatically removed
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when as long as the supplier and consumer devices themselves
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are still present.
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What: /sys/class/devlink/.../consumer
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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This file is a symlink to the consumer device's sysfs directory.
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What: /sys/class/devlink/.../runtime_pm
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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This file indicates if the device link has any impact on the
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runtime power management behavior of the consumer and supplier
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devices. For example: Making sure the supplier doesn't enter
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runtime suspend while the consumer is active.
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This will be one of the following strings:
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'0' - Does not affect runtime power management
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'1' - Affects runtime power management
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What: /sys/class/devlink/.../status
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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This file indicates the status of the device link. The status
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of a device link is affected by whether the supplier and
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consumer devices have been bound to their corresponding
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drivers. The status of a device link also affects the binding
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and unbinding of the supplier and consumer devices with their
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drivers and also affects whether the software state of the
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supplier device is synced with the hardware state of the
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supplier device after boot up.
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See also: sysfs-devices-state_synced.
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This will be one of the following strings:
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'not tracked'
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'dormant'
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'available'
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'consumer probing'
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'active'
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'supplier unbinding'
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'unknown'
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'not tracked' means this device link does not track the status
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and has no impact on the binding, unbinding and syncing the
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hardware and software device state.
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'dormant' means the supplier and the consumer devices have not
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bound to their driver.
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'available' means the supplier has bound to its driver and is
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available to supply resources to the consumer device.
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'consumer probing' means the consumer device is currently
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trying to bind to its driver.
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'active' means the supplier and consumer devices have both
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bound successfully to their drivers.
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'supplier unbinding' means the supplier devices is currently in
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the process of unbinding from its driver.
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'unknown' means the state of the device link is not any of the
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above. If this is ever the value, there's a bug in the kernel.
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What: /sys/class/devlink/.../supplier
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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This file is a symlink to the supplier device's sysfs directory.
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What: /sys/class/devlink/.../sync_state_only
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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This file indicates if the device link is limited to only
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affecting the syncing of the hardware and software state of the
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supplier device.
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This will be one of the following strings:
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'0'
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'1' - Affects runtime power management
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'0' means the device link can affect other device behaviors
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like binding/unbinding, suspend/resume, runtime power
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management, etc.
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'1' means the device link will only affect the syncing of
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hardware and software state of the supplier device after boot
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up and doesn't not affect other behaviors of the devices.

‎Documentation/ABI/testing/sysfs-devices-consumer

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What: /sys/devices/.../consumer:<consumer>
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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The /sys/devices/.../consumer:<consumer> are symlinks to device
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links where this device is the supplier. <consumer> denotes the
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name of the consumer in that device link. There can be zero or
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more of these symlinks for a given device.

‎Documentation/ABI/testing/sysfs-devices-state_synced

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What: /sys/devices/.../state_synced
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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The /sys/devices/.../state_synced attribute is only present for
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devices whose bus types or driver provides the .sync_state()
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callback. The number read from it (0 or 1) reflects the value
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of the device's 'state_synced' field. A value of 0 means the
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.sync_state() callback hasn't been called yet. A value of 1
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means the .sync_state() callback has been called.
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Generally, if a device has sync_state() support and has some of
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the resources it provides enabled at the time the kernel starts
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(Eg: enabled by hardware reset or bootloader or anything that
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run before the kernel starts), then it'll keep those resources
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enabled and in a state that's compatible with the state they
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were in at the start of the kernel. The device will stop doing
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this only when the sync_state() callback has been called --
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which happens only when all its consumer devices are registered
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and have probed successfully. Resources that were left disabled
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at the time the kernel starts are not affected or limited in
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any way by sync_state() callbacks.
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‎Documentation/ABI/testing/sysfs-devices-supplier

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What: /sys/devices/.../supplier:<supplier>
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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The /sys/devices/.../supplier:<supplier> are symlinks to device
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links where this device is the consumer. <supplier> denotes the
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name of the supplier in that device link. There can be zero or
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more of these symlinks for a given device.

‎Documentation/ABI/testing/sysfs-devices-waiting_for_supplier

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What: /sys/devices/.../waiting_for_supplier
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Date: May 2020
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Contact: Saravana Kannan <[email protected]>
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Description:
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The /sys/devices/.../waiting_for_supplier attribute is only
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present when fw_devlink kernel command line option is enabled
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and is set to something stricter than "permissive". It is
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removed once a device probes successfully (because the
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information is no longer relevant). The number read from it (0
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or 1) reflects whether the device is waiting for one or more
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suppliers to be added and then linked to using device links
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before the device can probe.
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A value of 0 means the device is not waiting for any suppliers
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to be added before it can probe. A value of 1 means the device
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is waiting for one or more suppliers to be added before it can
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probe.

‎Documentation/admin-guide/kernel-parameters.txt

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useful to also enable the page_owner functionality.
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on: enable the feature
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debugfs= [KNL] This parameter enables what is exposed to userspace
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and debugfs internal clients.
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Format: { on, no-mount, off }
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on: All functions are enabled.
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no-mount:
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Filesystem is not registered but kernel clients can
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access APIs and a crashkernel can be used to read
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its content. There is nothing to mount.
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off: Filesystem is not registered and clients
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get a -EPERM as result when trying to register files
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or directories within debugfs.
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This is equivalent of the runtime functionality if
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debugfs was not enabled in the kernel at all.
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Default value is set in build-time with a kernel configuration.
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debugpat [X86] Enable PAT debugging
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decnet.addr= [HW,NET]

‎Documentation/driver-api/driver-model/platform.rst

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Embedded systems frequently need one or more clocks for platform devices,
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which are normally kept off until they're actively needed (to save power).
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System setup also associates those clocks with the device, so that that
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System setup also associates those clocks with the device, so that
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calls to clk_get(&pdev->dev, clock_name) return them as needed.
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‎drivers/base/base.h

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struct klist_node knode_class;
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struct list_head deferred_probe;
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struct device_driver *async_driver;
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char *deferred_probe_reason;
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struct device *device;
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u8 dead:1;
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};
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extern void driver_detach(struct device_driver *drv);
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extern int driver_probe_device(struct device_driver *drv, struct device *dev);
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extern void driver_deferred_probe_del(struct device *dev);
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extern void device_set_deferred_probe_reason(const struct device *dev,
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struct va_format *vaf);
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static inline int driver_match_device(struct device_driver *drv,
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struct device *dev)
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{

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