EDID describing subpixel ordering

[Jon Smirl]

Did this get implemented? If so can we use this to get rid of the
dialog in X setup for doing this?


Microsoft is developing a proposal to VESA to allow the identification
of these characteristics in the monitor EDID (Extended Display
Identification Data). For displays that are connected via a plug and
play interface that support DDC (display data channel) through a
digital interface, such as the new Digital Visual Interface, it is
recommended that monitor manufacturers implement the enhanced EDID.
For devices that have an integrated display and that use a digital
interface that does not support DDC, the display driver can return the
appropriate flags. The display driver can also override the monitor
settings, for cases such as landscape/portrait switching.

Displaced Subpixel Rendering

Future display developments are expected to take advantage of
displaced subpixel rendering to improve rendering quality. For optimal
quality, it should be possible for GDI+ to query the physical pixel
attributes of the display device. It is recommended that the graphics
device be able to convey the following information about each of the
connected display devices:

1. Whether the display device is an LCD screen.

2. Whether the display device is connected to the graphics device via
a digital connection, such as DVI. Digital connections for LCDs, such
as the Digital Video Interface (DVI) are preferred, since they provide
more accurate displaced subpixel rendering quality. For more details
on DVI, see http://www.ddwg.org This link leaves the Microsoft.com
site.

3. Striping of the LCD, and whether it's horizontal or vertical. The
pixels of most color LCDs are composed of red, green and blue
fragments in a horizontal or vertical orientation, and this
configuration is known as the "striping." Vertical striping, where the
screen is composed of vertical strips of red, green, and blue
fragments, is preferred since it effectively provides three separate
fragments in a row for every pixel, thereby giving more horizontal
subpixel resolution.

4. Ordering of the LCD color fragments. The color fragments may be
ordered R-G-B or B-G-R from left-to-right or top-to-bottom. Note that
this is independent of the RGB ordering of the frame buffer.

5. Whether the LCD screen is operating in its native pixel resolution,
or whether it is a scaled resolution. Because of the nature of
displaced subpixel rendering, its quality is reduced when a pixel in
the frame buffer is mapped to more than one physical pixel on the LCD
screen. An example of this is when the native resolution is 1024x768,
but the current mode is 640x480, and the device scales the output to
fill the entire screen.

6. Gamma of the display. This may be any value from 1.0 to 2.4,
although it is recommended that the display device use the sRGB gamma.

-- 
Jon Smirl
jonsmirl at gmail.com