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Diffstat (limited to 'Documentation/admin-guide/media/cec.rst')
| -rw-r--r-- | Documentation/admin-guide/media/cec.rst | 168 |
1 files changed, 133 insertions, 35 deletions
diff --git a/Documentation/admin-guide/media/cec.rst b/Documentation/admin-guide/media/cec.rst index 5c7259371494..b2e7a300494a 100644 --- a/Documentation/admin-guide/media/cec.rst +++ b/Documentation/admin-guide/media/cec.rst @@ -42,10 +42,14 @@ dongles): ``persistent_config``: by default this is off, but when set to 1 the driver will store the current settings to the device's internal eeprom and restore it the next time the device is connected to the USB port. + - RainShadow Tech. Note: this driver does not support the persistent_config module option of the Pulse-Eight driver. The hardware supports it, but I have no plans to add this feature. But I accept patches :-) +- Extron DA HD 4K PLUS HDMI Distribution Amplifier. See + :ref:`extron_da_hd_4k_plus` for more information. + Miscellaneous: - vivid: emulates a CEC receiver and CEC transmitter. @@ -55,6 +59,15 @@ Miscellaneous: you can control the CEC line through this driver. This supports error injection as well. +- cec-gpio and Allwinner A10 (or any other driver that uses the CEC pin + framework to drive the CEC pin directly): the CEC pin framework uses + high-resolution timers. These timers are affected by NTP daemons that + speed up or slow down the clock to sync with the official time. The + chronyd server will by default increase or decrease the clock by + 1/12th. This will cause the CEC timings to go out of spec. To fix this, + add a 'maxslewrate 40000' line to chronyd.conf. This limits the clock + frequency change to 1/25th, which keeps the CEC timings within spec. + Utilities ========= @@ -296,69 +309,71 @@ broadcast messages twice to reduce the chance of them being lost. Specifically Making a CEC debugger ===================== -By using a Raspberry Pi 2B/3/4 and some cheap components you can make +By using a Raspberry Pi 4B and some cheap components you can make your own low-level CEC debugger. -Here is a picture of my setup: - -https://hverkuil.home.xs4all.nl/rpi3-cec.jpg - -It's a Raspberry Pi 3 together with a breadboard and some breadboard wires: - -http://www.dx.com/p/diy-40p-male-to-female-male-to-male-female-to-female-dupont-line-wire-3pcs-356089#.WYLOOXWGN7I - -Finally on of these HDMI female-female passthrough connectors (full soldering type 1): +The critical component is one of these HDMI female-female passthrough connectors +(full soldering type 1): https://elabbay.myshopify.com/collections/camera/products/hdmi-af-af-v1a-hdmi-type-a-female-to-hdmi-type-a-female-pass-through-adapter-breakout-board?variant=45533926147 -We've tested this and it works up to 4kp30 (297 MHz). The quality is not high -enough to pass-through 4kp60 (594 MHz). - -I also added an RTC and a breakout shield: +The video quality is variable and certainly not enough to pass-through 4kp60 +(594 MHz) video. You might be able to support 4kp30, but more likely you will +be limited to 1080p60 (148.5 MHz). But for CEC testing that is fine. -https://www.amazon.com/Makerfire%C2%AE-Raspberry-Module-DS1307-Battery/dp/B00ZOXWHK4 +You need a breadboard and some breadboard wires: -https://www.dx.com/p/raspberry-pi-gpio-expansion-board-breadboard-easy-multiplexing-board-one-to-three-with-screw-for-raspberry-pi-2-3-b-b-2729992.html#.YGRCG0MzZ7I - -These two are not needed but they make life a bit easier. +http://www.dx.com/p/diy-40p-male-to-female-male-to-male-female-to-female-dupont-line-wire-3pcs-356089#.WYLOOXWGN7I -If you want to monitor the HPD line as well, then you need one of these -level shifters: +If you want to monitor the HPD and/or 5V lines as well, then you need one of +these 5V to 3.3V level shifters: https://www.adafruit.com/product/757 (This is just where I got these components, there are many other places you can get similar things). +The ground pin of the HDMI connector needs to be connected to a ground +pin of the Raspberry Pi, of course. + The CEC pin of the HDMI connector needs to be connected to these pins: -CE0/IO8 and CE1/IO7 (pull-up GPIOs). The (optional) HPD pin of the HDMI -connector should be connected (via a level shifter to convert the 5V -to 3.3V) to these pins: IO17 and IO27. The (optional) 5V pin of the HDMI -connector should be connected (via a level shifter) to these pins: IO22 -and IO24. Monitoring the HPD an 5V lines is not necessary, but it is helpful. +GPIO 6 and GPIO 7. The optional HPD pin of the HDMI connector should +be connected via the level shifter to these pins: GPIO 23 and GPIO 12. +The optional 5V pin of the HDMI connector should be connected via the +level shifter to these pins: GPIO 25 and GPIO 22. Monitoring the HPD and +5V lines is not necessary, but it is helpful. -This kernel patch will hook up the cec-gpio driver correctly to -e.g. ``arch/arm/boot/dts/bcm2837-rpi-3-b-plus.dts``:: +This device tree addition in ``arch/arm/boot/dts/bcm2711-rpi-4-b.dts`` +will hook up the cec-gpio driver correctly:: - cec-gpio@7 { + cec@6 { compatible = "cec-gpio"; - cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; - hpd-gpios = <&gpio 17 GPIO_ACTIVE_HIGH>; - v5-gpios = <&gpio 22 GPIO_ACTIVE_HIGH>; + cec-gpios = <&gpio 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; + hpd-gpios = <&gpio 23 GPIO_ACTIVE_HIGH>; + v5-gpios = <&gpio 25 GPIO_ACTIVE_HIGH>; }; - cec-gpio@8 { + cec@7 { compatible = "cec-gpio"; - cec-gpios = <&gpio 8 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; - hpd-gpios = <&gpio 27 GPIO_ACTIVE_HIGH>; - v5-gpios = <&gpio 24 GPIO_ACTIVE_HIGH>; + cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; + hpd-gpios = <&gpio 12 GPIO_ACTIVE_HIGH>; + v5-gpios = <&gpio 22 GPIO_ACTIVE_HIGH>; }; +If you haven't hooked up the HPD and/or 5V lines, then just delete those +lines. + This dts change will enable two cec GPIO devices: I typically use one to send/receive CEC commands and the other to monitor. If you monitor using an unconfigured CEC adapter then it will use GPIO interrupts which makes monitoring very accurate. +If you just want to monitor traffic, then a single instance is sufficient. +The minimum configuration is one HDMI female-female passthrough connector +and two female-female breadboard wires: one for connecting the HDMI ground +pin to a ground pin on the Raspberry Pi, and the other to connect the HDMI +CEC pin to GPIO 6 on the Raspberry Pi. + The documentation on how to use the error injection is here: :ref:`cec_pin_error_inj`. ``cec-ctl --monitor-pin`` will do low-level CEC bus sniffing and analysis. @@ -367,3 +382,86 @@ it later using ``--analyze-pin``. You can also use this as a full-fledged CEC device by configuring it using ``cec-ctl --tv -p0.0.0.0`` or ``cec-ctl --playback -p1.0.0.0``. + +.. _extron_da_hd_4k_plus: + +Extron DA HD 4K PLUS CEC Adapter driver +======================================= + +This driver is for the Extron DA HD 4K PLUS series of HDMI Distribution +Amplifiers: https://www.extron.com/product/dahd4kplusseries + +The 2, 4 and 6 port models are supported. + +Firmware version 1.02.0001 or higher is required. + +Note that older Extron hardware revisions have a problem with the CEC voltage, +which may mean that CEC will not work. This is fixed in hardware revisions +E34814 and up. + +The CEC support has two modes: the first is a manual mode where userspace has +to manually control CEC for the HDMI Input and all HDMI Outputs. While this gives +full control, it is also complicated. + +The second mode is an automatic mode, which is selected if the module option +``vendor_id`` is set. In that case the driver controls CEC and CEC messages +received in the input will be distributed to the outputs. It is still possible +to use the /dev/cecX devices to talk to the connected devices directly, but it is +the driver that configures everything and deals with things like Hotplug Detect +changes. + +The driver also takes care of the EDIDs: /dev/videoX devices are created to +read the EDIDs and (for the HDMI Input port) to set the EDID. + +By default userspace is responsible to set the EDID for the HDMI Input +according to the EDIDs of the connected displays. But if the ``manufacturer_name`` +module option is set, then the driver will take care of setting the EDID +of the HDMI Input based on the supported resolutions of the connected displays. +Currently the driver only supports resolutions 1080p60 and 4kp60: if all connected +displays support 4kp60, then it will advertise 4kp60 on the HDMI input, otherwise +it will fall back to an EDID that just reports 1080p60. + +The status of the Extron is reported in ``/sys/kernel/debug/cec/cecX/status``. + +The extron-da-hd-4k-plus driver implements the following module options: + +``debug`` +--------- + +If set to 1, then all serial port traffic is shown. + +``vendor_id`` +------------- + +The CEC Vendor ID to report to connected displays. + +If set, then the driver will take care of distributing CEC messages received +on the input to the HDMI outputs. This is done for the following CEC messages: + +- <Standby> +- <Image View On> and <Text View On> +- <Give Device Power Status> +- <Set System Audio Mode> +- <Request Current Latency> + +If not set, then userspace is responsible for this, and it will have to +configure the CEC devices for HDMI Input and the HDMI Outputs manually. + +``manufacturer_name`` +--------------------- + +A three character manufacturer name that is used in the EDID for the HDMI +Input. If not set, then userspace is responsible for configuring an EDID. +If set, then the driver will update the EDID automatically based on the +resolutions supported by the connected displays, and it will not be possible +anymore to manually set the EDID for the HDMI Input. + +``hpd_never_low`` +----------------- + +If set, then the Hotplug Detect pin of the HDMI Input will always be high, +even if nothing is connected to the HDMI Outputs. If not set (the default) +then the Hotplug Detect pin of the HDMI input will go low if all the detected +Hotplug Detect pins of the HDMI Outputs are also low. + +This option may be changed dynamically. |