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Intel® Embedded Graphics Drivers FAQ

Dual display configurations

1.  I installed the graphics driver for dual-display configuration, and it does not appear in the correct configuration (for example, the primary and secondary display appear to be swapped). How do I fix this?

 

When installing or re-installing the graphics driver, switch off the extended display mode.

 

2.  What are the display configurations supported by Intel® Embedded Graphics Drivers and the Intel® System Controller Hub (Intel® SCH) US15W chipset?

 

Four display configurations are currently supported by Intel Embedded Graphics Drivers and Intel SCH US15W.

 

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

 

3.  What are the differences in display configurations supported by Intel Embedded Graphics Drivers and the Intel System Controller Hub US15W chipset?

 

Single: Only one display active; supported by any operating system supported by Intel Embedded Graphics Drivers. Single display’s hardware configuration is comprised of one frame buffer, one pipe, and one port.

 

Regarding dual-display configurations:

 

  • Twin configuration/mode is not supported by the Intel SCH US15 series chipset. Twin configuration is supported by next generation chipsets and Intel® Graphics Media Accelerator Driver (Intel® GMA Driver) where content is driven to two display devices, each of which has the same content, resolution, and timings. From a hardware perspective, twin configuration is comprised of one frame buffer, one pipe, and two ports.
  • Clone configuration is supported by Intel SCH US15 series chipsets. From a hardware perspective, clone is comprised of one frame buffer, two pipes, and two ports.
  • Extended configuration is supported by Intel SCH US15 series chipsets. From a hardware perspective, extended is comprised of two frame buffers, two pipes, and two ports. Windows* XP uses the term “extended” to describe how the OS 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, 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 frame buffer map to each of the independent display frame buffers. Intel developed display manager software integrated into Intel Embedded Graphics Drivers that is enabled when a system is running in extended configuration.
  • DIH is supported by Intel SCH US15 series chipsets. From a hardware perspective, DIH is comprised of two frame buffers, two pipes, and two ports. DIH is the Linux* equivalent of extended configuration for multiple display support.

 

4.  What are the major differences between 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 drives two displays simultaneously with distinct, independent, non-continuous content, each with independent resolutions.

 

A single widescreen image cannot straddle two monitors in DIH but can do so in the Windows extended configuration and in the Linux Xinerama configuration (with limitations).

 

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

 

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

 

5.  What is the difference between vertical extended and Xinerama dual-display configurations?

 

Vertical extended is a Windows term, and Xinerama is a Linux feature/application/tool. The Intel System Controller Hub US15W chipset and other embedded Intel chipsets (Intel® Q45/G41/G45, GM45/GL40/GS45, Q35, GME965, GLE960/GME965, 945GME/945GSE/945G, Q965, 915GME/915GV, 910GMLE, 852GM, 852GME, 855GME chipsets) support both dual-display configurations to the limits of the application and operating system. Xinerama has more limits than the Windows XP/XPE/CE built-in operating system feature called extended or vertical extended. See also the glossary term "Xinerama."

 

6.  Do Intel Embedded Graphics Drivers and the Intel System Controller Hub US15W chipset support vertical extended configuration under Windows CE?

 

Yes. Intel Embedded Graphics Drivers and the Intel SCH US15W chipset support vertical extended configuration (VExt) under Windows CE. Configuration EDitor (CED) needs to be configured appropriately per the instructions in the user guide to enable vertical extended configuration. VExt is a dual display configuration under Windows CE only.

 

7.  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 by checking the box for “Extend my Windows desktop onto this monitor,” and then click "Apply."

 

8.  Can I configure a dual-SDVO system with the Intel Embedded Graphics Drivers?

 

Yes. Graphics memory controller hub (GMCH) drives serial digital video output (SDVO) via SDVO ports. Based on the chipset type, the numbers of available SDVO ports are different. If your next generation chipset has multiple SDVO ports, these SDVO ports can drive multiple SDVO devices (for example, video graphics array (VGA) encoder, digital visual interface* (DVI*) encoder, low-voltage differential signaling (LVDS) controller, and so on). For dual SDVO, it is necessary to specify the addresses of the two devices in your configuration.

 

Note: The Intel System Controller Hub US15W/US15WP/WPT chipset cannot enable a dual-SDVO system because it has only a single SDVO port supporting pixel clock speeds from 20 MHz to 160 MHz.

 

9.  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 Embedded Graphics Drivers support this configuration if the 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 specific implementation instructions.

 

10.  How is twin display different from clone display?

 

Twin display is a display configuration in which two displays are driven by the same set of timings. Both display devices should support those timings (resolution, refresh, and so on), where clone display is a display configuration in which two displays can each have an independent set of timings. Intel Embedded Graphics Drivers support both twin and clone configurations. See the user guide for more information.

 

Note: Intel System Controller Hub US15W chipset does not support twin configuration because the Intel SCH US15W hardware requires that the integrated LVDS controller must be on its own pipe; therefore twin cannot be supported. Twin configuration is possible with most GenX Intel chipsets however.

 

11.  Can I get an overlay surface on every display?

 

Yes. Starting with Intel Embedded Graphics Driver 7.0 on certain chipsets, a second overlay is available as a driver feature. Note: Graphics memory controller hub (GMCH) has only one dedicated hardware overlay surface. This overlay can be attached to either one of the displays but not to both. The one exception is if you are running in twin configuration, you can see the overlay image on both displays. This is because the twin displays share the same timings and a single pipe is driving both displays. The latest Intel Embedded Graphics Drivers simulate the hardware overlay capability on a second independent or clone display.

 

12.  The default graphics driver keeps selecting the CRT to be the primary display and the internal LVDS as the secondary display. How do I change the CRT to be the secondary display?

 

The configuration file needs to be configured to select which display to use as the primary display. Refer to the user guide for configuration instructions.

 

13.  Why do I get a green/grey window instead of the video playback on the cloned display?

 

This hardware limitation was eliminated starting with the Intel Embedded Graphics Driver 7.0 release. This used to occur because Intel chipsets have only one overlay surface to be able to display the XVideo overlay on one graphics pipe at a time. The XOrg driver allocates the XVideo overlay to the primary display when operating with a cloned display enabled. With a 7.0 driver and up, a second overlay capability has been added such that XVideo should be able to display on multiple displays. Another solution is that the XVideoBlend overlay does support multiple graphics pipes and will work when in a cloned display. In your XF86Config file, you can disable XVideo with the line 'Option “XVideo” “No”' in the driver device section. Enable XVideoBlend with the line 'Option “XVideoBlend” “Yes”.' The same restrictions apply when using a dual independent head configuration. XVideoBlend can be enabled and display an overlay on both displays.

 

14.  What are all the serial-digital video-out (SDVO) devices supported by Intel Embedded Graphics Drivers currently for second-display outputs?

 

The user guide receives regular updates and lists all SDVO devices currently supported by Intel Embedded Graphics Drivers via port drivers. The SDVO devices listed in the table below are supported by Intel Embedded Graphics Drivers currently for second display outputs.

Device VBIOS/EPOG/EFI Video Driver Support Graphics Driver Support
Internal TV out No Yes
Chrontel* CH7022 RGB VGA/SDTV/HDTV out Yes Yes
Chrontel CH7307 Single-port DVI* out Yes Yes
Chrontel CH7308 LVDS out Yes Yes
Internal LVDS Yes Yes
Chrontel CH7317 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

 

15.  Can a user run OpenGL* (OGL) or OpenGL ES (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.

 

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

 

For Intel SCH US15 chipsets and Intel® Atom™ processor E6xx series, you can run OGL and OGLES when running Xinerama. However, it will not be hardware accelerated rendering. It is expected to be very slow. For other platforms such as 3rd generation and 4th generation, OGL is not supported when running Xinerama configuration due to X-Server limitations.

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