System having capability for daisy-chained serial distribution of video display data

• US 8,723,756 B2
• Filed: 01/15/2008
• Issued: 05/13/2014
• Est. Priority Date: 01/15/2008
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Kim, Jechan
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US12/014,341
• Publication Number:
  US 20090182917A1
• Time in Patent Office: 2,310 Days
• Field of Search: 345 11- 3, 345 96-100, 345204-215
• US Class Current: 345/1.3
• CPC Class Codes: G06F 3/1431 using a single graphics controller
• CPC Class Codes: G06F 3/1438 using more than one graphics controller
• CPC Class Codes: G09G 2370/042 for monitor identification
• CPC Class Codes: G09G 2370/045 using multiple communication channels, e.g. parallel and serial
• CPC Class Codes: G09G 2370/10 Use of a protocol of communication by packets in interfaces along the display data pipeline
• CPC Class Codes: G09G 2370/12 Use of DVI or HDMI protocol in interfaces along the display data pipeline
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: G09G 5/391 Resolution modifying circuits, e.g. variable screen formats

Abstract

A serial display interface such as the VESA-Display Port interface is expanded to support daisy chained coupling of one display monitor to the next. Each daisy chain wise connectable display monitor (except optionally the most downstream one on the daisy chain) has a local daisy chain transceiver device associated with it where the local transceiver device routes a selectable one or more video data streams to the local monitor and the local transceiver device relays on to more downstream devices of the daisy chain other video data streams. In one embodiment, the daisy chain wise connectable display monitors are hot-pluggable and unpluggable.

Claims

1. A video display apparatus for displaying an image represented by received video signals, the apparatus comprising:

(a) a first port structured to receive a first plurality of serially transmitted digital signals representing one or more video images;

(b) a second port structured to output a second plurality of serially transmitted digital signals representing one or more of the video images of said first port;

(c) a relaying circuit coupled to the first and second ports, the relaying circuit comprising;

a router that can selectively route part or all of one or more data streams representing at least part of one of the video images of said first port toward a local monitor or to said second port; and

an auxiliary channel relay configured to bidirectionally relay serial auxiliary channel data, wherein the relayed auxiliary channel data includes Extended Display Identification Data (EDID) indicating physical attributes of at least one of one or more local monitors that can be operatively coupled to a daisy chain communication circuit defined by the auxiliary channel relay.

2. The video display apparatus of claim 1 wherein:

said first port includes a Video Electronics Standards Association (VESA) DisplayPort compatible first interface plug; and

said second port includes a VESA-DisplayPort compatible second interface plug.

3. The video display apparatus of claim 2 and further comprising:

a local monitor operatively coupled to the to the relaying circuit for displaying the image represented by one or more of the data streams that are selectively routed by the selective router toward said local monitor.

4. The video display apparatus of claim 1 wherein:

said relaying circuit includes a hot-plug detector that can detect when a second video display apparatus similar to said video display apparatus is connected daisy chain style to the second port.

5. A method of daisy chain connecting a plurality of video display units to a video source device where the video source device can output a first plurality of serially transmitted digital signals representing one or more video images, the method comprising:

(a) detecting when a first video sink device has been connected daisy chain style to a video signal relaying circuit driven by the video source device; and

(b) in response to said detection of the connection of the first video sink device, automatically assigning one or more of a first plurality of video carrying data lanes to serially carry video data stream signals representing an image or part of an image to be displayed by a monitor associated with the first video sink device; and

(c) in response to said detection of the connection of the first video sink device, automatically configuring other video sink devices that are interposed daisy chain style in the video signal relaying circuit between the video source device and the first video sink device to relay part or all of the video data stream signals of the lanes assigned to the first video sink device to the first video sink device and selectively routing part or all of the video data stream signals to the next-in-chain video sink device.

6. The daisy chain connecting method of claim 5 and further comprising:

(d) in response to said detection of the connection of the first video sink device, automatically reading local Extended Display Identification Data (EDID) data in the first video sink device where the local EDID data indicates physical attributes of at least one local display monitor associated with the first video sink device.

7. The daisy chain connecting method of claim 5 and further comprising:

(d) in response to said detection of the connection of the first video sink device, automatically reading local Display Port Configuration Data (DPCD) data in the first video sink device where the local DPCD data indicates a current reconfigurable configuration of at least one local display monitor associated with the first video sink device.

8. A daisy chain transceiver device comprising:

(a) a first plurality of video stream data receivers each structured to receive video stream data serially transmitted over a corresponding ingress serial data link and to deserialize the received video stream data;

(b) a second plurality of video stream data routers each coupled and structured to receive deserialized video stream data output by a corresponding one of the video stream data receivers and to selectively route part or all of the deserialized video stream to a programmably defined destination;

(c) a third plurality of video stream data transmitters each coupled and structured to receive routed data from one of the video stream data routers and to serialize the routed data and to serially transmit the reserialized data over a corresponding egress serial data link; and

(d) a local output port coupled and structured to receive routed data from one or more of the video stream data routers and to forward the routed and locally received data to a local display monitor.

9. The daisy chain transceiver device of claim 8 and further comprising:

(e) a local policy maker structured to store local Display Port Configuration Data (DPCD) data and local Extended Display Indentification Data (EDID) data; and

(f) auxiliary channel data transceivers coupled to the local policy maker and structured to relay auxiliary channel data upstream and downstream of the daisy chain transceiver device.

10. The daisy chain transceiver device of claim 9 wherein:

(e.1) said local policy maker includes an extended DPCD register set having a daisy chain support register which contains an extended syntax flag for indicating whether an extended AUX_CH syntax is being currently implemented by the daisy chain transceiver device.

11. The daisy chain transceiver device of claim 9 wherein:

(e.1) said local policy maker includes an extended DPCD register set having a daisy chain support register which contains a sink device identification field that can provide the daisy chain transceiver device with a unique device identification distinguishing the daisy chain transceiver device from other sink devices along a daisy chain that the daisy chain transceiver device is connected to as a sink device.

12. The daisy chain transceiver device of claim 9 wherein:

(e.1) said local policy maker includes an extended DPCD register set having a daisy chain support register which contains an active ingress lanes indicator filed for indicating which of said first plurality of video stream data receivers is coupled to a currently active ingressing video lane.

13. The daisy chain transceiver device of claim 9 wherein:

(e.1) said local policy maker includes an extended DPCD register set having a daisy chain support register which contains an active egress lanes indicator filed for indicating which of said third plurality of video stream data transmitters is coupled to a currently active egressing video lane.

14. The daisy chain transceiver device of claim 9 wherein:

(e.1) said local policy maker includes an extended DPCD register set having a daisy chain support register which contains a 24 bit unit identification field for uniquely identifying the daisy chain transceiver device as an organizational unit within a predefined organization of other uniquely identifiable units.

15. The daisy chain transceiver device of claim 9 wherein:

(f.1) said auxiliary channel data transceivers are further structured to relay hot-plug detection signals from downstream sink devices along the daisy chain in which the daisy chain transceiver device resides to upstream devices.

16. The daisy chain transceiver device of claim 9 wherein:

(e.1) said local policy maker is structured to respond to command packets relayed to it by way of one or more auxiliary channel data transceivers when the command packet contains a destination identification field designating the daisy chain transceiver device as a target of the command.

17. The daisy chain transceiver device of claim 9 wherein:

(e.1) said local policy maker is structured to output command response packets by way of one of its auxiliary channel data transceivers where the command response packet contains a sink device identification field designating the daisy chain transceiver device as the source of the command response packet.

18. A daisy chain supporting source device comprising:

(a) a first plurality of video stream data generators each structured to formulate video stream data for serial transmission over a corresponding egress serial data link and to serialize the formulated video stream data prior to output;

(b) a second plurality of video data stream control units each coupled to a respective one of said video stream data generators and structured to control the formulation of said video stream data for serial transmission so that the formulation is compatible with a target display monitor that is intended to display an image represented by the video data stream, the video data stream control units being programmable so as support different ones of target display monitors; and

(c) a source side policy maker structured to retrieve local Display Port Configuration Data (DPCD) data and local Extended Display Identification Data (EDID) data from a plurality of daisy chain connected monitors and to store the retrieved DPC data and EPI data in said second plurality of video data stream control units.

19. The daisy chain supporting source device of claim 18 and further comprising:

(d) a host interface port operatively coupled to the source side policy maker and to the first plurality of video stream data generators for enabling an external host device to download video data into the video stream data generators and to interact with the source side policy maker.

20. The daisy chain supporting source device of claim 18 wherein each video stream data generator includes a graphics data processor and a video data storage memory.

21. The daisy chain supporting source device of claim 18 wherein:

(c.1) said source side policy maker includes an extended DPCD register set having a daisy chain support register which contains an extended syntax flag for indicating whether an extended AUX_CH syntax is being currently implemented by the daisy chain supporting source device.

22. The daisy chain supporting source device of claim 18 wherein:

(c.1) said source side policy maker includes an extended DPCD register set having a daisy chain support register which contains a 24 bit unit identification field for uniquely identifying the daisy chain supporting source device as an organizational unit within a predefined organization of other uniquely identifiable units.

23. The daisy chain supporting source device of claim 18 wherein:

(c.1) said source side policy maker is structured to output command packets by way of an auxiliary data channel where the command packets each contains a destination device identification field designating a daisy chain connected device that is intended to respond to the command packet.

24. The daisy chain supporting source device of claim 23 wherein:

(c.2) said source side policy maker is structured to receive command response packets by way of the auxiliary data channel where the command response packets each contains a responder identification field designating a daisy chain connected device that is the source of the command response packet.