System Having Capability for Daisy-Chained Serial Distribution of Video Display Data

• US 20090278763A1
• Filed: 05/06/2008
• Published: 11/12/2009
• Est. Priority Date: 05/06/2008
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Kim, Jechan, Zeng, Xuming Henry
• Granted Patent: US 8,237,624 B2
• Time in Patent Office: Days
• US Class Current: 345/1.100
• CPC Class Codes: G06F 3/1431 using a single graphics controller
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2370/042 for monitor identification
• CPC Class Codes: G09G 2370/047 using display data channel standard [DDC] communication
• 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 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

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 has a local daisy chain transceiver device associated with it where the local transceiver device selectively picks off passing through video data streams in response to embedded MDID identification signals and forwards the selectively picked off data to the local monitor. The local transceiver device also relays the passing through video data streams on to more downstream devices of the daisy chain. 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 transmitted over a corresponding first plurality of lanes and representing at least part of a video image that possibly may or may not be displayed by said video display apparatus;

(b) a second port structured to output a second plurality of serially transmitted digital signals over a corresponding second plurality of lanes and also representing said at least part of the video image;

(c) a relaying circuit coupled to the first and second ports, the relaying circuit including pas-through buffers for relaying said serially transmitted digital signals from the first port to the second port; and

(d) a selective data processing means which selectively processes the passing-through serially transmitted digital signals in response to multi-device identification (MDID) signals embedded in each of the passing-through serially transmitted digital signals.

2. The video display apparatus of claim 1 wherein:

said first port includes a 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 selective data processing means for displaying the at least part of the video image represented by the first plurality of serially transmitted digital signals that are selectively processed by the data processing means.

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. The video display apparatus of claim 1 wherein:

said relaying circuit includes an auxiliary channel relay that can bidirectionally relay serial auxiliary channel data, where the relayed auxiliary channel data includes EDID data 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.

6. 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 over a corresponding first plurality of lanes to representing at least part of a video image, 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 fetching local characterizing data from the first video sink device indicative of characteristics of a local display functions associated with the first video sink device.

7. The daisy chain connecting method of claim 6 wherein said fetching of local characterizing data includes:

automatically reading local 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.

8. The daisy chain connecting method of claim 6 wherein said fetching of local characterizing data includes:

automatically reading local 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.

9. 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;

(b) a local data processor coupled to said first plurality of video stream data receivers and structured to deserialize on-the-fly selected portions of the received video stream data of the first plurality of video stream data receivers;

(b) a second plurality of video stream data buffers each coupled and structured to receive video stream data output by a corresponding one of the video stream data receivers and to buffer the video stream data;

(c) a third plurality of video stream data transmitters each coupled and structured to receive buffered serial data from a corresponding one of the video stream data buffers and to relay the buffered serial data over a corresponding egress serial data link; and

(d) a local output port coupled to the local data processor and structured to forward the on-the-fly selected and deserialized portions of the passing through video data to a local display monitor.

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

(e) a local policy maker structured to store local DPCD data and local EPI 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.

11. The daisy chain transceiver device of claim 10 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.

12. The daisy chain transceiver device of claim 10 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.

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

said sink device identification field can support at least 5 uniquely identifiable sink devices or at least 5 uniquely identifiable bands of video data.

14. The daisy chain transceiver device of claim 10 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 10 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 10 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 10 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 real or virtual video stream data generators each structured to formulate video stream data for serial transmission as a burst of plural serial signals over a corresponding plurality of egress serial data links;

(b) a data packer that packages said formulate video stream data for serial transmission as a burst of plural serial signals over the corresponding plurality of egress serial data links;

(c) a second plurality of video data stream control units each coupled to a respective one of said real or virtual 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 or a part of 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

(d) a source side policy maker structured to retrieve local DPCD data and local EPI data from a plurality of daisy chain connected monitor units and to store the retrieved DPCD 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:

(e) 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 19 wherein at least one of said video stream data generators is implemented by a combination of 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.