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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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David NyströmandAlexandre Belloni
8ea0b60bc0
Allow userspace to request dynamic address assignment, which is useful for i3cdev devices with broken hot-join support. This will assign dynamic addresses to all devices on the I3C bus which are currently unassigned. Signed-off-by: David Nyström <david.nystrom@est.tech> Reviewed-by: Frank Li <Frank.Li@nxp.com> Reviewed-by: Meagan Lloyd <meaganlloyd@linux.microsoft.com> Link: https://patch.msgid.link/20260219-i3c_rescan-v6-1-b81d6cc3cb30@est.tech Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
195 lines
7.2 KiB
Plaintext
195 lines
7.2 KiB
Plaintext
What: /sys/bus/i3c/devices/i3c-<bus-id>
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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An I3C bus. This directory will contain one sub-directory per
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I3C device present on the bus.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/current_master
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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Expose the master that owns the bus (<bus-id>-<master-pid>) at
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the time this file is read. Note that bus ownership can change
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overtime, so there's no guarantee that when the read() call
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returns, the value returned is still valid.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/mode
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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I3C bus mode. Can be "pure", "mixed-fast" or "mixed-slow". See
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the I3C specification for a detailed description of what each
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of these modes implies.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/i3c_scl_frequency
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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The frequency (expressed in Hz) of the SCL signal when
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operating in I3C SDR mode.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/i2c_scl_frequency
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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The frequency (expressed in Hz) of the SCL signal when
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operating in I2C mode.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/dynamic_address
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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Dynamic address assigned to the master controller. This
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address may change if the bus is re-initialized.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/bcr
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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BCR stands for Bus Characteristics Register and express the
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device capabilities in term of speed, maximum read/write
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length, etc. See the I3C specification for more details.
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This entry describes the BCR of the master controller driving
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the bus.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/dcr
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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DCR stands for Device Characteristics Register and express the
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device capabilities in term of exposed features. See the I3C
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specification for more details.
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This entry describes the DCR of the master controller driving
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the bus.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/pid
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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PID stands for Provisioned ID and is used to uniquely identify
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a device on a bus. This PID contains information about the
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vendor, the part and an instance ID so that several devices of
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the same type can be connected on the same bus.
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See the I3C specification for more details.
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This entry describes the PID of the master controller driving
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the bus.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/hdrcap
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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Expose the HDR (High Data Rate) capabilities of a device.
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Returns a list of supported HDR mode, each element is separated
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by space. Modes can be "hdr-ddr", "hdr-tsp" and "hdr-tsl".
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See the I3C specification for more details about these HDR
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modes.
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This entry describes the HDRCAP of the master controller
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driving the bus.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/hotjoin
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KernelVersion: 6.8
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Contact: linux-i3c@vger.kernel.org
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Description:
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I3C’s Hot-Join mechanism allows an I3C Device to inform the
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Active Controller that a newly-joined Target is present on the
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I3C Bus and is ready to receive a Dynamic Address, in order to
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become fully functional on the Bus. Hot-Join is used when the
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Target is mounted on the same I3C bus and remains depowered
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until needed or until the Target is physically inserted into the
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I3C bus
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This entry allows to enable or disable Hot-join of the Current
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Controller driving the bus.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/<bus-id>-<device-pid>
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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An I3C device present on I3C bus identified by <bus-id>. Note
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that all devices are represented including the master driving
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the bus.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/<bus-id>-<device-pid>/dynamic_address
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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Dynamic address assigned to device <bus-id>-<device-pid>. This
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address may change if the bus is re-initialized.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/<bus-id>-<device-pid>/bcr
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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BCR stands for Bus Characteristics Register and express the
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device capabilities in term of speed, maximum read/write
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length, etc. See the I3C specification for more details.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/<bus-id>-<device-pid>/dcr
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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DCR stands for Device Characteristics Register and express the
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device capabilities in term of exposed features. See the I3C
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specification for more details.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/<bus-id>-<device-pid>/pid
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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PID stands for Provisioned ID and is used to uniquely identify
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a device on a bus. This PID contains information about the
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vendor, the part and an instance ID so that several devices of
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the same type can be connected on the same bus.
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See the I3C specification for more details.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/<bus-id>-<device-pid>/hdrcap
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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Expose the HDR (High Data Rate) capabilities of a device.
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Returns a list of supported HDR mode, each element is separated
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by space. Modes can be "hdr-ddr", "hdr-tsp" and "hdr-tsl".
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See the I3C specification for more details about these HDR
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modes.
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What: /sys/bus/i3c/devices/<bus-id>-<device-pid>
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KernelVersion: 5.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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These directories are just symbolic links to
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/sys/bus/i3c/devices/i3c-<bus-id>/<bus-id>-<device-pid>.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/<bus-id>-<device-pid>/dev_nack_retry_count
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KernelVersion: 6.18
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Contact: linux-i3c@vger.kernel.org
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Description:
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Expose the dev_nak_retry_count which controls the number of
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automatic retries that will be performed by the controller when
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the target device returns a NACK response. A value of 0 disables
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the automatic retries. Exist only when I3C constroller supports
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this retry on nack feature.
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What: /sys/bus/i3c/devices/i3c-<bus-id>/do_daa
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KernelVersion: 7.0
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Contact: linux-i3c@vger.kernel.org
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Description:
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Write-only attribute that triggers a Dynamic Address Assignment
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(DAA) procedure which discovers new I3C devices on the bus.
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Writing a boolean true value (1, y, yes, true, on) to this
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attribute causes the master controller to perform DAA, which
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includes broadcasting an ENTDAA (Enter Dynamic Address Assignment)
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Common Command Code (CCC) on the bus. Writing a false value
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returns -EINVAL.
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This is useful for discovering I3C devices that were not present
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during initial bus initialization and are unable to issue
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Hot-Join. Only devices without a currently assigned dynamic address
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will respond to the ENTDAA broadcast and be assigned addresses.
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Note that this mechanism is distinct from Hot-Join, since this is
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controller-initiated discovery, while Hot-Join is device-initiated
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method to provoke controller discovery procedure.
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