admin-guide/media/cec.rst

1 .. SPDX-License-Identifier: GPL-2.0
12 - Exynos4
13 - Exynos5
14 - STIH4xx HDMI CEC
15 - V4L2 adv7511 (same HW, but a different driver from the drm adv7511)
16 - stm32
17 - Allwinner A10 (sun4i)
18 - Raspberry Pi
19 - dw-hdmi (Synopsis IP)
20 - amlogic (meson ao-cec and ao-cec-g12a)
21 - drm adv7511/adv7533
22 - omap4
23 - tegra
24 - rk3288, rk3399
25 - tda998x
26 - DisplayPort CEC-Tunneling-over-AUX on i915, nouveau and amdgpu
27 - ChromeOS EC CEC
28 - CEC for SECO boards (UDOO x86).
29 - Chrontel CH7322
34 - adv7604/11/12
35 - adv7842
36 - tc358743
41 - Pulse-Eight: the pulse8-cec driver implements the following module option:
45 - RainShadow Tech. Note: this driver does not support the persistent_config
46   module option of the Pulse-Eight driver. The hardware supports it, but I
47   have no plans to add this feature. But I accept patches :-)
51 - vivid: emulates a CEC receiver and CEC transmitter.
54 - cec-gpio. If the CEC pin is hooked up to a GPIO pin then
58 - cec-gpio and Allwinner A10 (or any other driver that uses the CEC pin
60   high-resolution timers. These timers are affected by NTP daemons that
71 Utilities are available here: https://git.linuxtv.org/v4l-utils.git
73 ``utils/cec-ctl``: control a CEC device
75 ``utils/cec-compliance``: test compliance of a remote CEC device
77 ``utils/cec-follower``: emulate a CEC follower device
79 Note that ``cec-ctl`` has support for the CEC Hospitality Profile as is
82 Note that the libcec library (https://github.com/Pulse-Eight/libcec) supports
104 To test: hook up your DP-to-HDMI adapter to a CEC capable device
107 	cec-ctl --playback	# Configure the PC as a CEC Playback device
108 	cec-ctl -S		# Show the CEC topology
110 The ``cec-ctl -S`` command should show at least two CEC devices,
117 USB-C to HDMI
118 -------------
120 Samsung Multiport Adapter EE-PW700: https://www.samsung.com/ie/support/model/EE-PW700BBEGWW/
122 Kramer ADC-U31C/HF: https://www.kramerav.com/product/ADC-U31C/HF
124 Club3D CAC-2504: https://www.club-3d.com/en/detail/2449/usb_3.1_type_c_to_hdmi_2.0_uhd_4k_60hz_acti…
127 -------------------
129 Club3D CAC-1080: https://www.club-3d.com/en/detail/2442/displayport_1.4_to_hdmi_2.0b_hdr/
131 …ion (SKU: CD0712): https://www.cablecreation.com/products/active-displayport-to-hdmi-adapter-4k-hdr
133 …I True 4k Adapter (P/N 2JA63AA): https://www.hp.com/us-en/shop/pdp/hp-displayport-to-hdmi-true-4k-…
135 Mini-DisplayPort to HDMI
136 ------------------------
138 Club3D CAC-1180: https://www.club-3d.com/en/detail/2443/mini_displayport_1.4_to_hdmi_2.0b_hdr/
147 whereas with the PS176 it is more hit-and-miss (mostly miss). The PS186 is
156 utility to create the ``/dev/cecX`` devices. Support for the Pulse-Eight
162 …ERNEL=="ttyACM[0-9]*", ATTRS{idVendor}=="2548", ATTRS{idProduct}=="1002", ACTION=="add", TAG+="sys…
163 …ERNEL=="ttyACM[0-9]*", ATTRS{idVendor}=="2548", ATTRS{idProduct}=="1001", ACTION=="add", TAG+="sys…
164 …NEL=="ttyACM[0-9]*", ATTRS{idVendor}=="04d8", ATTRS{idProduct}=="ff59", ACTION=="add", TAG+="syste…
168 For Pulse-Eight make /lib/systemd/system/pulse8-cec-inputattach@.service::
171 	Description=inputattach for pulse8-cec device on %I
175 	ExecStart=/usr/bin/inputattach --pulse8-cec /dev/%I
177 For the RainShadow Tech make /lib/systemd/system/rainshadow-cec-inputattach@.service::
180 	Description=inputattach for rainshadow-cec device on %I
184 	ExecStart=/usr/bin/inputattach --rainshadow-cec /dev/%I
187 For proper suspend/resume support create: /lib/systemd/system/restart-cec-inputattach.service::
195 …-c 'for d in /dev/serial/by-id/usb-Pulse-Eight*; do /usr/bin/inputattach --daemon --pulse8-cec $d;…
200 And run ``systemctl enable restart-cec-inputattach``.
203 EDID changes, you can use ``cec-ctl`` with the ``-E`` option::
205 	cec-ctl -E /sys/class/drm/card0-DP-1/edid
207 This assumes the dongle is connected to the card0-DP-1 output (``xrandr`` will tell
212 ``crontab -e`` and add this line::
214 	@reboot /usr/local/bin/cec-ctl -E /sys/class/drm/card0-DP-1/edid
220 CEC Without HPD
226 adapters can support this. An example is the Odroid-U3 SBC that has a
227 level-shifter that is powered off when the HPD signal is low, thus
228 blocking the CEC pin. Even though the SoC can use CEC without a HPD,
229 the level-shifter will prevent this from functioning.
243 1) Get a Pulse-Eight USB CEC dongle, connect an HDMI cable from your
244    device to the Pulse-Eight, but do not connect the Pulse-Eight to
247    Now configure the Pulse-Eight dongle::
249 	cec-ctl -p0.0.0.0 --tv
253 	sudo cec-ctl -M
257 	cec-ctl --playback
262 	cec-ctl -t0 --image-view-on
264    The Pulse-Eight should see the <Image View On> message. If not,
269    Pulse-Eight to a CEC-enabled display and run the same command
270    on your device: now there is a HPD, so you should see the command
271    arriving at the Pulse-Eight.
273 2) If you have another linux device supporting CEC without HPD, then
275    two HDMI outputs together. You won't have a HPD (which is what we
280 If CEC messages do not come through when there is no HPD, then you
282 or the software powers off the CEC core when the HPD goes low. The
292 have timing issues. This is hard to discover unless you can hook up a low-level
309 your own low-level CEC debugger.
311 The critical component is one of these HDMI female-female passthrough connectors
314 …om/collections/camera/products/hdmi-af-af-v1a-hdmi-type-a-female-to-hdmi-type-a-female-pass-throug…
316 The video quality is variable and certainly not enough to pass-through 4kp60
322 http://www.dx.com/p/diy-40p-male-to-female-male-to-male-female-to-female-dupont-line-wire-3pcs-3560…
324 If you want to monitor the HPD and/or 5V lines as well, then you need one of
336 GPIO 6 and GPIO 7. The optional HPD pin of the HDMI connector should
339 level shifter to these pins: GPIO 25 and GPIO 22. Monitoring the HPD and
342 This device tree addition in ``arch/arm/boot/dts/bcm2711-rpi-4-b.dts``
343 will hook up the cec-gpio driver correctly::
346 		compatible = "cec-gpio";
347 		cec-gpios = <&gpio 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
348 		hpd-gpios = <&gpio 23 GPIO_ACTIVE_HIGH>;
349 		v5-gpios = <&gpio 25 GPIO_ACTIVE_HIGH>;
353 		compatible = "cec-gpio";
354 		cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
355 		hpd-gpios = <&gpio 12 GPIO_ACTIVE_HIGH>;
356 		v5-gpios = <&gpio 22 GPIO_ACTIVE_HIGH>;
359 If you haven't hooked up the HPD and/or 5V lines, then just delete those
368 The minimum configuration is one HDMI female-female passthrough connector
369 and two female-female breadboard wires: one for connecting the HDMI ground
375 ``cec-ctl --monitor-pin`` will do low-level CEC bus sniffing and analysis.
376 You can also store the CEC traffic to file using ``--store-pin`` and analyze
377 it later using ``--analyze-pin``.
379 You can also use this as a full-fledged CEC device by configuring it
380 using ``cec-ctl --tv -p0.0.0.0`` or ``cec-ctl --playback -p1.0.0.0``.