Devices, systems, and methods for instant video switching in an extension environment
Extension devices such as upstream facing port devices (UFP devices) and downstream facing port devices (DFP devices) connect via an extension medium. When a UFP device and a DFP device pair with each other, DisplayPort video and/or audio information from a DisplayPort source device can be presented by a DisplayPort sink device, which are coupled to the UFP device and DFP device, respectively. In some embodiments, the DFP device may train a DisplayPort link to the DisplayPort sink device regardless of whether it is receiving actual data from a UFP device, and may provide placeholder data to the DisplayPort sink device in order to keep the link active. The DFP device may then replace the placeholder data with the actual data from the UFP device, once received, and may thereby seamlessly switch the DisplayPort sink device from presenting placeholder data to presenting data from the DisplayPort source device.
1. A method of switching DisplayPort connections over an extension medium, the method comprising:
conducting, by an extension device, link training with a DisplayPort sink device to establish a DisplayPort link between the extension device and the DisplayPort sink device;
generating, by the extension device, placeholder video data;
generating, by the extension device, DisplayPort data that includes the placeholder video data;
transmitting, by the extension device, the DisplayPort data that includes the placeholder video data to the DisplayPort sink device;
receiving, by the extension device via the extension medium, actual video data, wherein the actual video data is generated by a DisplayPort source device;
generating, by the extension device, DisplayPort data that includes the actual video data; and
transmitting, by the extension device, the DisplayPort data that includes the actual video data to the DisplayPort sink device without re-training the link between the extension device and the DisplayPort sink device.
2. The method of claim 1 , wherein the placeholder video data and the actual video data have matching timing.
3. The method of claim 1 , wherein timing of the actual video data and timing of the placeholder video data is different, and wherein the method further comprises:
generating, by the extension device, DisplayPort data that includes at least five idle patterns; and
transmitting, by the extension device, the DisplayPort data that includes at least five idle patterns between the DisplayPort data that includes the placeholder video data and the DisplayPort data that includes the actual video data.
4. The method of claim 1 , wherein the actual video data is first actual video data received from a first extension device connected to a first DisplayPort source device, and wherein the method further comprises:
receiving, by the extension device, a command to pair to a second extension device connected to a second DisplayPort source device;
receiving, by the extension device via the extension medium, second actual video data from the second extension device;
generating, by the extension device, DisplayPort data that includes the second actual video data instead of the first actual video data; and
transmitting, by the extension device, the DisplayPort data that includes the second actual video data instead of the first actual video data to the DisplayPort sink device without re-training the link between the extension device and the DisplayPort sink device.