2. XF86Config options

The driver should be able to probe the presence of a SPC8110 chip. If the driver fails to probe the chip correctly define the chip explicitly in the screen section.

Device Section Entries and Options Currently Supported:

Chipset "spc8110"

May be specified if probing fails or to accelerate server startup. The value must be "spc8110".

VideoRam kilobytes

If specified the value (in kilobytes) will be used, otherwise the amount of memory will be probed on startup.

Option "sw_cursor"

Disables the use of the hardware cursor. The hardware cursor requires one Kbyte of video memory as pattern storage area. If you need the full amount of video memory you may want to disable the hardware cursor using this option. Also the hardware cursor code was not tested with cursor images larger than 64 pixels (high or wide), so if you use large images you may have to disable the hardware cursor.

Option "no_linear"

Disables the use of the linear aperture. If this option is set the driver will use the standard VGA memory window at 0xa0000 otherwise it will map the whole video memory.

Membase baseaddress

In VLB/486LB configuration the linear aperture address will be set to 0x03E0.0000, in PCI configuration the address will be read from the PCI configuration space. The base address in VLB/486LB systems may be set to any value using the "Membase" definition.

Option "noaccel"

Disables the use of the Bitblt engine. Normally the driver accelerates screen-to-screen copy operations and solid fills.

Since the SPC8110 puts certain restrictions on the use of the Bitblt engine you will notice different performance between certain operations (eg window movement). If this is a problem for your application you may want to disable the accelerator.

Option "fifo_moderate"

Option "fifo_conservative"

Usually the driver computes the FIFO threshold values for the SPC8110's write buffer correctly. However for certain modes (eg the 832x624 mode shown below) the FIFO is programmed too aggressively which leads to streaks in the display during screen updates. With option "fifo_moderate" the computed FIFO low request level is incremented by one with "fifo_conservative" it is incremented by two.