ET6000 driver features

Information for Tseng Chipset Users : ET6000 driver features
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## 3. ET6000 driver features

In addition to the features in the ET4000 driver, the SVGA ET6000 server supports all possible color depths in the SVGA server: 8bpp, 16bpp (both at 5-5-5 and 5-6-5 color resolutions), 24bpp and 32 bpp.

In order to be able to run at a depth of 16bpp, 24bpp, or 32bpp, and to improve performance at 8bpp, linear addressing must be enabled.

Linear memory mode (as opposed to the default, banked memory layout) is supported. It is required and enabled by default for the 16/24/32 bpp modes. For 8bpp, the default is banked mode.

To force linear memory at 8bpp, put the following in the SVGA section of your `XF86Config`:

      Option "linear"

Acceleration is supported and is enabled by default, and accelerates all color depths on the ET6000. Acceleration can be disabled by adding the following in the Device section of your `XF86Config`:

      Option "noaccel"

The hardware cursor is supported in all color depths. Due to a hardware limitation in the ET6000, only a limited set of colors is supported (2 significant bits per color component). This may cause some (small) cursor color errors. If absolute cursor color accuracy is required, the hardware cursor should not be enabled. However, in most applications, this will not be a problem. The hardware cursor can be enabled using

      Option "hw_cursor"

There is a problem with the hardware cursor at high dotclocks (above approx. 110MHz) at which point the cursor does strange things when partly off the left-hand side of the screen.

Doublescan modes currently don't work with the hardware cursor: only the top half of the cursor is visible. If you want to use DoubleScan modes (320x200 is a popular one), then do not enable the hardware cursor.

On some fast systems, acceleration may cause occasional font corruption. Until this problem is fixed, font acceleration may be disabled using the following in the Device section of your `XF86Config`:

      Option "xaa_no_color_exp"

When using accelerated high color-depths (24bpp and 32bpp), high-resolution modes (starting somewhere around 800x600) may cause temporary "garbage" lines to the right of the screen while the accelerator is busy. The garbage should not be persistent: it should go away as soon as the server is left alone. This is a memory bandwidth problem, and thus cannot be resolved (except by not allowing such modes at all, which is what is done in the current driver).

Ignoring it is one option (it isn't destructive). Disabling acceleration in the Device section of the `XF86Config` file is another option: since the accelerator is not being used, there is ample bandwidth to avoid such problems.

Information for Tseng Chipset Users : ET6000 driver features
Previous: ET4000 driver features
Next: Clock selection problems with some ET4000 boards