The included display drivers are based on the Matrox driver source
included with XFree86. Modifications made by Matrox include the
addition of the Matrox HAL library, which can be optionally
installed to enable Matrox specific features.
This display driver supports the option of using your main and
secondary displays as if they were a single display ("merged"
displays) divided between your two monitors. If your system is
configured for 3D acceleration, this feature allows for 3D
acceleration on both your displays at the same time.
The DualHead Multi-Display - Merged feature is available on G450-
and G550- based products only. Please take note that this feature
does not support DVI monitors in XFree86 4.3.0, and X.org versions
6.7.0, 6.8.0, 6.8.1, 6.8.2, 6.9.0, 7.0.0.
The Matrox HAL ("Hardware Abstraction Layer") is a special library
to enable features not supported by the standard XFree86 driver.
It's required for DualHead, TV output, and DVI support with G400-
based graphics hardware, for multi-display support with G200/G450 MMS
products, and for DVI support. The HAL library is not required for
basic DualHead support (without a DVI monitor) with G450- and G550-based
graphics hardware. Also please take not that TV output is not supported
with G450- and G550- based graphics hardware in Linux.