Browse Prior Art Database

Super Video Graphics Array Support by Notebook PC

IP.com Disclosure Number: IPCOM000112823D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Itoh, H: AUTHOR [+3]

Abstract

This article describes the display driver of a notebook PC which supports Super Video Graphics Array (SVGA) for high resolution CRT (greater than 640x480 resolution) and Liquid Crystal Display (LCD). The display driver of the PC automatically selects the appropriate resolution based on the status of display (simultaneous display of CRT and LCD, CRT only display, or LCD only display).

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This is the abbreviated version, containing approximately 76% of the total text.

Super Video Graphics Array Support by Notebook PC

      This article describes the display driver of a notebook PC
which supports Super Video Graphics Array (SVGA) for high resolution
CRT (greater than 640x480 resolution) and Liquid Crystal Display
(LCD).  The display driver of the PC automatically selects the
appropriate resolution based on the status of display (simultaneous
display of CRT and LCD, CRT only display, or LCD only display).

      Two registers ("Register 1" and "Register 2") are prepared to
enable the above automatic selection of display resolution.
"Register 1" stores the maximum resolution which the PC can support
in a specific display status (CRT+LCD, LCD, or CRT).  "Register 2"
stores the resolution in which the display driver actually operates.
"Register 1" is written by the POST(Power On Self Test)/BIOS(Basic
Input/Output System) or the resume program of the PC based on the
display status (CRT+LCD, LCD, or CRT).  Display driver is loaded with
an appropriate resolution based on the value of "Register 1".  The
selected resolution of the driver is written to the "Register 2".

      Operation Example 1.  If both the 640x480 LCD and the CRT which
can display up to 1024x768 are enabled, POST/BIOS sets "Register 1"
to 640x480.  The driver selects the resolution automatically to
640x480 based on the information of "Register 1".

      Operation Example 2.  When the system starts with only the CRT
(up to 1024x678) and the driver operate...