Computer systems with built-in visual displays are becoming ubiquitous. Such computer systems are often realized in portable computers such as laptops. Different types of portable computers, and different software applications that run on those computers, offer an enormous variety of capabilities. Many computers now include more than one video system for generating video signals that drive the display. For example, some computers have a primary video system that provides a primary video signal and a separate graphics subsystem that provides its own video signal. The primary video system handles alpha-numeric characters and some graphics, and the separate graphics subsystem handles more advanced graphics. Depending on which function the computer is performing, the appropriate video signal is routed to the display. A computer with a built-in display often has a video output port that outputs a video signal. A separate display may be connected to such a port. For example, a user may desire a display that is physically larger, and therefore easier to read and capable of displaying more data and better graphics, than the built-in display. Video output ports and their associated circuitry typically comply with such standards as VGA, to output analog video signals, and DVI, to output digital video signals. The Video Electronics Standards Association has developed a digital video display interface known as DisplayPort. The current DisplayPort standard, version 1.2, became effective Dec. 22, 2009.
The drawings illustrate by example implementations of the invention.
In the drawings and in this description, examples and details are used to illustrate principles of the invention. Other configurations may suggest themselves. Parameters such as voltages, particular components, and component values are approximate. Some known methods and structures have not been described in detail in order to avoid obscuring the invention. Methods defined by the claims may comprise steps in addition to those listed, and except as indicated in the claims themselves the steps may be performed in another order than that given. Accordingly, the invention may be practiced without limitation to the details and arrangements as described. The invention is to be limited only by the claims, not by the drawings or this description.
A user of a computer system such as a laptop with a built-in display, more than one internal video source, and a video port, must deal with a variety of possible video configurations. There has been a need for a user-friendly way to manage these configurations.
In the above method, the system first checks for an external video signal because it is likely that, if a user has connected an external video source, the user wants to use the display with that source. If the user has not connected an external source, it is likely that the user wants to display the video output signal from a graphics subsystem rather than the signal from the primary video subsystem if a graphic subsystem video signal is present. Some embodiments give the user the option of overriding these choices. These embodiments include checking for a user selection of a video signal for display (27), and if the user has selected a video signal, routing the selected video signal to the display (29). This gives the user the ability to manually override the automatic selections otherwise made by the system.
In some embodiments checking for a graphics subsystem video signal may mean simply checking whether a graphics subsystem is present. This reflects an assumption that if such a system is connected, it is providing a graphics subsystem video signal.
In some embodiments, if an external video signal is not present and a video signal from an internal source is being displayed, an alternate video signal from that internal source is routed to an external video port (31). The external video port is then ready if the user connects an external display. The alternate video signal is provided in suitable format for routing to an external display, for example VGA, DVI, or DisplayPort, and may be provided in more than one format through appropriate connectors as desired.
In some embodiments, if an external video signal is being routed to the display, unused circuits may be powered down (33), for example to save energy.
The external-video control signal may be provided by an external video source connected to the video port. For example, in the DisplayPort protocol, a voltage of 3 volts or more on an AUX connector pin in the DisplayPort indicates that an external video source is present. Conversely, the absence of such a voltage indicates that no external video source is present.
In some embodiments the first and second multiplexers are responsive to a video-selection command from a user to route the graphics-subsystem video signal, the primary video signal, or the external video signal to the display regardless of any indications of the graphics-subsystem control signal and the external-video control signal. This is indicated symbolically by a source control unit 59 that receives the graphics-subsystem control signal from the graphics subsystem (or from a sensor that senses connection of the graphics subsystem) on a line 61 and the external-video control signal from the video port on a line 63. In the absence of an overriding command from a user, the source control unit connects the external-video control signal on the line 63 to the line 47, and the graphics-subsystem control signal on the line 61 to the line 41. An override command from a user causes appropriate signals to be sent over the lines 47 and 41 to cause the video signal desired by the user to be routed to the display. In an actual embodiment the source control unit might be implemented by logic circuits or by machine instructions that control a computer system that includes the video subsystem.
In some embodiments a third multiplexer 65 is responsive to the external-video control signal to route an alternate video signal from a fourth multiplexer 67 as carried on a line 69 to the video port. In the embodiment shown, the alternate video signal is carried on the line 49 to the port 35, but in other embodiments a separate line and a separate video port might be used. The alternate signal may be provided in suitable format, as discussed above, and one or more connectors may be used as needed. The fourth multiplexer 67 is responsive to the graphics-subsystem control signal to select an alternate (external-output) graphics-subsystem video signal on a line 73 or an alternate primary video signal on a line 75 and provide the selected external-output video signal to the third multiplexer on the line 69. The primary video subsystem 77 and the graphics subsystem 79 each provide primary and alternate video signals , the primary one for the internal display being selected by the multiplexer 37 and the alternate one for the video port being selected by the multiplexer 67.
A computer system 81 with automatic video configuration for multiple video sources is shown in
In some embodiments the central processor is responsive to a video-selection command from a user to cause the first and second multiplexers to route the graphics-subsystem video signal, the primary video signal, or the external video signal to the display regardless of any indications of the graphics-subsystem control signal and the external-video control signal. This is the function that is indicated symbolically by the source control unit 59 in
In some embodiments the machine instructions cause the central processor to power down unneeded circuits when the external video signal is being routed to the display.
Embodiments as discussed above provide a system that automatically configures itself to display the video signal most likely to be desired by a user while giving the user the option to change the configuration as desired. This allows for a more intuitive user experience whether or not the user knows any special key sequences and eliminates any need to boot any particular operating system or to run a specific application.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2011/058083 | 10/27/2011 | WO | 00 | 4/10/2014 |