White square around the mouse cursor

[stephen239955_st]

Posted on November 19, 2002 at 04:29

White square around the mouse cursor

[stephen239955_st]

Posted on November 15, 2002 at 10:04

We have a white distorted box around the mouse while running the X-Server on the STPC. What is happening?

[thierry239955_st]

Posted on November 19, 2002 at 04:29

Hardware cursor is very sensible to memory bandwidth. It is the first device to be affected by a slow access to RAM. You probably have wrong settings for memory or have voluntary configure a slow access.

The settings to check are:

- the memory clock: MCLK for SDRAM based chip, GCLK for EDO/FPM based chip. This clocks are configurable by software or through the BIOS setup (except for MCLK when synchronized with HCLK - HCLK and MCLK are then configured by HCLK straps option).

- the RAS and CAS latency settings. This settings are also configurable by software or BIOS.

If all this settings are OK, you can play with water mark settings of the graphics FIFO: reg 0x1b and 0x27 of the CRTC (accessible at indexed I/O 0x3d4/0x3d5). There are always a way to compensate a memory bandwidth problem uses this 2 registers. This two registers are reset when you start the X-Server (in fact at any graphics screen initialization). You have to start the X-Server before to modify them.