Managing display data of different types for transmission to multiple devices

The method of 4, wherein the processing the combined data or the cursor combined data comprises any one or more of:

• flipping, mirroring, rotating, dithering, blending, colour correcting, scaling or other transformations of the display data;
• mapping the display data according to requirements of the particular display device for which the display data is destined;
• compressing;
• or
• converting into a display specific protocol format for the particular display device for which the display data is destined.

A video display controller configured to perform:

• fetching display data of a first type destined for the first display device from a first portion of a first buffer memory and display data of a second type destined for the first display device from a first portion of a second buffer memory at a first time according to an arbitration control signal, the first buffer memory having stored therein respective display data of the first type for respective display devices in respective portions thereof and the second buffer memory having stored therein respective display data of the second type for respective display devices in respective portions thereof;
• combining, by a first combining engine, the fetched display data of the first and second types destined for the first display device into combined display data destined for display on the first display device;
• fetching display data of the first type destined for the second display device from a second portion of the first buffer memory and display data of the second type destined for the second display device from a second portion of the second buffer memory at a second time, different to the first time, according to the arbitration control signal;
• combining, by the first combining engine, the fetched display data of the first and second types destined for the second display device into combined display data destined for display on the second display device;
• time multiplexing the combined display data destined for the first display device with the combined display data for the second display device into a single display data stream;
• and
• outputting the single display data stream,
• wherein the video display controller configured to generate the arbitration control signal by:
• generating a virtual clock signal for each particular display device, by:
• receiving a local clock signal, wherein the local clock signal has a frequency that is a, or a multiple of a, sum of clock frequencies required for the plurality of display devices;
• fetching ratio information for the particular display device indicating a ratio between the clock frequency required for the particular display device and the local clock signal;
• counting a fraction of the local clock signal based on the ratio information;
• and
• outputting the virtual clock signal when the count reaches an integer value,
• using the virtual clock signal by:
• generating a horizontal synchronisation signal to be used to horizontally synchronise the display data on the particular display device:
• generating a vertical synchronisation signal to be used to vertically synchronise the display data on the particular display device;
• and
• generating an active pixel signal indicating that the display device includes a pixel value to be output, wherein the active pixel signal is used to increment an active pixel accumulator for the particular display device;
• and
• generating the arbitration control signal based on accumulation totals of each of the active pixel accumulators.