Graphics Adapters Basic Features

The adapter must support all VESA standard timings for all PC 98 required resolutions, including 640 × 480 × [8, 15, 16, 24] bpp, 800 × 600 × [8, 15, 16, 24] bpp, and 1024 × 768 × [8, 15, 16] bpp.

For a mobile PC’s external display support, the graphics subsystem must support the Basic PC 98 requirements. For a mobile PC’s internal display, see the requirements in the “Monitors” chapter in Part 4 of this guide.

For any PC 98 system that requires quality rendering of 2-D graphics, the minimum support is double buffering for up to 800 × 600 × 16 bpp. For any PC 98 system that requires 3-D rendering in any fashion, whether using software or hardware acceleration, the minimum requirements are 800 × 600 × 16 bpp double-buffered, Z buffer, and 1.25-MB local texture cache. On AGP systems, there is no requirement for local texture cache.

For future 3-D titles, the high triangle content will make increased demands on graphics bandwidth. High-performance designs for systems such as Entertainment PC 98 or Consumer PC 98 that will support Direct3D applications should provide sufficient 3-D texture access to meet the 3-D performance recommendations defined in the item “Hardware meets PC 98 3-D accelerator performance requirements” later in this chapter.

Texture compression can provide additional effective texture memory, and it also increases the effective memory bandwidth that is available.

Note: When the user selects 1024 × 768 resolution, by default the graphics adapter must use a non-interlaced refresh rate. A graphics adapter can default to 1024 × 768 interlaced mode in either of the following situations:

• The attached monitor is not DDC-compatible and the user has not selected a monitor type in the display control panel.
  
  
• The monitor does not support 1024 × 768 non-interlaced mode, as determined from the Extended Display Identification Data (EDID) or registry settings.

8. Adapter meets VESA specifications for ergonomic timing rates

Recommended: 85 Hz for 1024 × 768, non-interlaced.

The graphics adapter must support, at a minimum, the ergonomic timings documented in the current version of VESA and Industry Standards and Guidelines for Computer Display Monitor Timing for all resolutions up to 1280 × 1024 that are supported by the monitor. The minimum required support is 75 Hz for 1024 × 768, non-interlaced. Higher scan rates are preferable under standards published by VESA.

9. All supported color depths are enumerated

Required

The driver and INF file must enumerate all modes supported so that applications can choose their preferred color depth. The driver and INF file must follow the following guidelines for enumeration:

• At a minimum, either 5:5:5 or 5:6:5 modes must be supported.
  
  
• If only 5:5:5 mode is supported, the driver must also enumerate this as 16-bpp mode. This is required because some applications only look for 16-bpp support and will run in 8-bit mode if they fail to find a 16-bit mode.
  
  
• If both 5:5:5 and 5:6:5 modes are supported, both modes are enumerated.

For each color depth supported, color ordering must be implemented as shown in the following list. Color ordering is shown in the following table from the most-significant bit (MSB) to the least-significant bit (LSB.)