Patent Application
20090007158
In many computer systems, multiple displays can be coupled to a single system. For example, a personal computer (PC) may include multiple flat panel displays to enable viewing of greater amounts of information, clone mode information and so forth. While a graphics controller such as a graphics memory controller (GMC) may have multiple display planes including video planes and graphics planes, among others, that can provide display information to both a primary display and a clone display during normal execution, oftentimes this is not the case for pre-boot modes or legacy video modes such as a video graphics adapter (VGA) mode. That is, some graphics controllers have a hardware limitation that make it unable to provide VGA display information in a clone mode. Accordingly, certain display information such as status information during a pre-boot environment cannot be displayed in the system.
In various embodiments, a clone display coupled to a system having a primary display may operate during pre-boot and boot environments, even where a hardware limitation prevents display of video graphics adapter (VGA) data in clone mode. That is, in various embodiments, a request for VGA mode operation may be converted to a request for a different mode of operation such as a video electronics standards association (VESA) mode or another extended graphics mode such as a video basic input/output system (BIOS) extension (VBE) mode. In this way, display of status or other data in a clone mode may be realized during pre-boot and boot environments.
Referring now to
Accordingly, the execution of code in VESA function 34 and/or custom function 36 may lead to the output of data to a register/port interface 40 which in turn may be coupled to video hardware 50, which may be a graphics card that converts the data in accordance with a given graphics capability. Note further that multiple displays may be coupled to video hardware 50 by different pipes, including a first display 60, which may be a primary system display, and a second display 65, which may be a clone display. While shown with this particular implementation in the embodiment of
Thus using embodiments such as shown in
In various embodiments, in order to maintain backwards compatibility without affecting existing implementations, a mechanism may be provided to enable/disable embodiments. In one embodiment, a field configuration may be provided that holds a user configurable value to determine whether video BIOS should operate with clone mode enabled or disabled. In one embodiment, the field may be an integer value that is used to differentiate between enabling and disabling VESA mode conversion. Accordingly, the flag may be used to set both display pipes to VESA mode operation in the enabled state. In one embodiment, when in the enabled state, both pipes may follow the default mode specified in a configuration file. In order for both displays to be enabled, both pipes may be set to VESA mode, although the second pipe may already be active.
Referring now to
Referring still to
In various embodiments, certain video BIOS routines may be modified to implement embodiments of the present invention. For example, a dispatch function may be updated to enable VGA mode requests to be handled in VESA mode when clone display mode is active. Other implementations may update various functions such as a VBE function which may receive system BIOS calls. For example, a handler may be provided to check for VGA mode requests that are incoming. If clone mode is enabled, the handler may perform a conversion to translate the VGA mode request to a VESA mode request. Still further, color palettes may be updated to enable display of desired color information in VESA mode during clone operation.
Accordingly, various embodiments may be used to boot in clone mode to enable status displays on both a primary display and a clone mode display, as both display pipes may be transferred or forced into a VESA mode to enable VGA emulation in the VESA mode.
Referring now to
Embodiments may be implemented in code and may be stored on a storage medium having stored thereon instructions which can be used to program a system to perform the instructions. The storage medium may include, but is not limited to, any type of disk including floppy disks, optical disks, compact disk read-only memories (CD-ROMs), compact disk rewritables (CD-RWs), and magneto-optical disks, semiconductor devices such as read-only memories (ROMs), random access memories (RAMs) such as dynamic random access memories (DRAMs), static random access memories (SRAMs), erasable programmable read-only memories (EPROMs), flash memories, electrically erasable programmable read-only memories (EEPROMs), magnetic or optical cards, or any other type of media suitable for storing electronic instructions.
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
