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Intel® Embedded Media and Graphics Driver (Intel® EMGD) FAQ

Dual display configurations

1.  What are the serial digital video out (SDVO) devices supported by Intel® Embedded Media and Graphics Driver (Intel® EMGD) for additional display outputs for the Intel® Atom™ processor E6xx series and the Intel® System Controller Hub (Intel® SCH) US15W chipset?


The Intel EMGD user guide for the Intel Atom processor E6xx series and Intel SCH US15W chipset, receives regular updates and lists all SDVO devices currently supported by Intel EMGD via port drivers. The SDVO devices listed in the table below are supported by Intel EMGD currently for additional display outputs. Take note that dual displays with SDVO TV-out are not supported in the Intel Atom processor E6xx series (only) due to SDVO clipping software work-around.

Device VBIOS / EPOG / EFI Video Driver Support Graphics Driver Support
Chrontel CH7022* RGB VGA / SDTV / HDTV out
Yes Yes
Chrontel CH7307* single-port DVI out
Yes Yes
Chrontel CH7308* low-voltage differential signaling (LVDS) out
Yes Yes
Internal LVDS Yes Yes
Chrontel CH7317B* RGB VGA out Yes Yes
Chrontel CH7315* HDMI* out Yes Yes
Chrontel CH7319* dual-port DVI out with HDCP Yes Yes
Chrontel CH7320* dual-port DVI out Yes Yes
Silicon Image SiI* 1362 Yes Yes
Silicon Image SiI 1364 Yes Yes
OKI ML7213* IOH (specific to OKI board for Intel® Atom™ processor E6xx series only; limited support to Linux* MeeGo* 1.2 only) Yes Yes
Chrontel CH7036*-LVDS to HDMI / VGA / LVDS converter No Yes


2.  What are the display configurations supported by Intel EMGD?


Four display configurations are currently supported by Intel EMGD:

  • Single
  • Clone
  • Extended
  • Dual independent head (DIH)


3.  What are the differences in display configurations supported by Intel EMGD?


Single display: Only one display active, supported by any operating system supported by Intel EMGD. Single display’s hardware configuration is comprised of one framebuffer, one pipe, and one port.


Dual display: Clone configuration is supported. From a hardware perspective, Clone is comprised of one framebuffer, two pipes, and two ports.


Extended configuration is supported: From a hardware perspective, extended is comprised of two framebuffers, two pipes, and two ports. Windows* XP and Windows 7 use the term “extended” to describe how the operating system presents the multiple independent displays to the user. The primary feature of extended mode is that it allows a second display to become an additional part of the desktop area. If the operating system is Windows XP, XPe, or Windows 7, the user must use extended (not DIH)configuration. More specifically, extended configuration creates a single, large virtual frame buffer that is used by the applications. Separate areas of the virtual framebuffer map to each of the independent display framebuffers. Intel developed display manager software integrated into Intel EMGD that is enabled when a system is running in extended configuration. Xinerama* is the extended mode supported in the Linux* environment. MeeGo* distribution does not support Xinerama. Intel EMGD support on Xinerama is only on Fedora* distribution with the following limitations: no video playback and no hardware acceleration in 3-D mode.


DIH is supported: From a hardware perspective, DIH is comprised of two framebuffers, two pipes, and two ports. Linux’s DIH drives two displays simultaneously with distinct, independent, non-continuous content, each with independent resolutions.


4.  What are the major differences between Windows extended, Linux Xinerama, and DIH dual display configurations?


From a hardware perspective, DIH, Linux Xinerama, and Windows extended configurations are all the same.


Extended mode in Windows drives two displays simultaneously with continuous widescreen-like content, each with independent resolutions. Linux’s DIH configuration drives two displays simultaneously with distinct, independent, and non-continuous content, each with independent resolutions.


A single widescreen image cannot straddle two monitors in DIH configuration, but can do so in Windows extended configuration and in Linux Xinerama configuration with limitations. The MeeGo distribution does not support Xinerama. Intel EMGD support on Xinerama is only on Fedora distribution with the following limitations: no video playback and no hardware acceleration in 3-D mode.


DIH configuration at a hardware level has independent resolutions, refresh rates, and content, the same as extended configuration. In DIH configuration, the two monitors are active and they are logically distinct.


In addition, in DIH configuration, each image is locked to a single monitor. In extended configuration, two monitors are also active, but they form one large virtual desktop; that is, they are not logically distinct.


5.  How do I get the extended desktop on my Microsoft Windows XP or Windows XP Embedded system?


Go to “Display properties” and select the “Settings” tab. There you should see two displays. Select the second display and enable it for extended desktop configuration by checking the box for “Extend my Windows desktop onto this monitor,” and then click "Apply."


6.  How do I configure dual displays on my Microsoft Windows 7 or Windows Embedded Standard 7 system?


Clone and extended desktop configurations can be configured using the common user interface (CUI). You can access the CUI using various methods such as the desktop context menu, tray icon menu, Windows control panel, or through a pre-configured hot key.


7.  Can I configure two displays with different timings and different resolutions, but with the same content?


Yes, this is the clone dual display configuration. Intel EMGD supports this configuration if the graphics and memory controller hub (GMCH) has two pipes. Each pipe drives out different timings and eventually outputs to a display device. Check the clone configuration sections in the user guide for the appropriate platform for specific implementation instructions.


8.  Can a user run OGL or OGLES on both screens when running DIH configuration in Linux?


Yes, for all supported X server versions, a user can run OGL and OGLES on both screens with hardware acceleration.


9.    Can a user run OpenGL* or OpenGL ES on both screens when running Xinerama configuration in Linux?


For the Intel System Controller Hub US15W chipset and Intel Atom processor E6xx series, you can run OpenGL and OpenGL ES when running Xinerama; however, it will not use hardware accelerated rendering. It is expected to be very slow.


10.    I've seen some systems boot DOS with two displays. How is that possible?


Some VBIOS have been designed to use a less compatible technique of ignoring the mode set and use a Video Electronics Standards Association (VESA*) mode instead of the requested VGA mode to allow two displays to work. The embedded VBIOS has never done this because of compatibility risks and code space restrictions in the VBIOS code. Recently, some GMA drivers and VBIOS also have not implemented this workaround because their target use cases (tablet or cell phones) do not have a second display. Please see the using dual displays during startup or in DOS application note.


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