Datasheet

Functional Description
R
190 Datasheet
5.4.5 GMCH Planes and Engines
The GMCH display can be functionally delineated into Planes and Engines (Pipes and Ports). A
plane consists of rectangular shaped image that has characteristics such as source, size, position,
method, and format. These planes get attached to source surfaces, which are rectangular system
memory surfaces with a similar set of characteristics. They are also associated with a particular
destination pipe.
A pipe consists of a set of planes that will be combined and a timing generator. A port is the
destination for the result of the pipe. Therefore, planes are associated with pipes and pipes are
associated with ports.
5.4.5.1 Dual Pipe Independent Display Functionality
The display consists of two display pipes, A and B. Pipes have a set of planes that are assigned to
them as sources. The analog display port may only use Pipe A or Pipe B, DVOB and DVO C port
may use either Pipe A or Pipe B, and the LFP LVDS interface may only use Pipe B. This limits
the resolutions available on a digital display when an analog CRT is active.
Table 42. Dual Display Usage Model
Display Pipe A Display Pipe B
CRT LFP (Internal LVDS)
DVO B or DVO C or both CRT
CRT DVO B or DVO C or both (Simultaneous Scan)
DVO B or DVO C or both LFP (Internal LVDS)
CRT/DVO B or DVO C or both LFP (Internal LVDS)
5.4.6 Hardware Cursor Plane
The GMCH supports two hardware cursors. The cursor plane is one of the simplest display
planes. With a few exceptions, has a fixed size of 64 x 64 and a fixed Z-order (top). In legacy
modes, cursor can cause the display data below it to be inverted. In the alpha blend mode, true
color cursor data can be alpha blended into the display stream. It can be assigned to either display
pipe A or display pipe B and dynamically flipped from one to the other when both are running.
5.4.6.1 Cursor Color Formats
Color data can be in an indexed format or a true color format. Indexed data uses the entries in the
four-entry cursor palette to convert the two-bit index to a true color format before being passed to
the blenders. The index can optionally specify that a cursor pixel be transparent or cause an
inversion of the pixel value below it or one of two colors from the cursor palette. Blending of
YUV or RGB data is only supported with planes that have data of the same format.