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<A HREF="cirrus.html"><EM> Information for Cirrus Chipset Users</EM></A>
 <b>:</b> <EM>Basic configuration </EM><BR>
<b>Previous:</b> <A HREF="cirrus1.html"><EM>Supported chipsets </EM></A><BR>
<b>Next:</b> <A HREF="cirrus3.html"><EM>XF86Config options </EM></A>


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  <H2><A NAME="2"></A>2. Basic configuration </H2>

<p>It is recommended that you generate an XF86Config file using
the `<code>XF86Setup</code>' or `<code>xf86config</code>' program, which should
produce a working
high-resolution 8bpp configuration. You may want to include mode
timings in the <code>Monitor</code> section that better fit your monitor
(e.g 1152x900 modes). The driver options are described in detail in
the next section; here the basic options are hinted at.</p>
<p>For all chipsets, a <code>Clockchip "cirrus"</code> line in the
<code>Device</code> section can be useful. This allows the use of any dot
clocks, instead of one out of the fixed set of dot clocks supported
by the driver. This is required if you want a 12.6 MHz dot clock for
low-resolution modes. However, when this option used, clock frequencies
be unstable leading to strange effects, so only use it if absolutely
required.</p>
<p>For any chip with a BitBLT engine, the new XAA (XFree86 Acceleration
Architecture) is used. This code is new and still in a beta stage.
If graphics redrawing goes wrong, try the
<code>"noaccel"</code> option; if it is using memory-mapped I/O,
<code>"no_mmio"</code> might be sufficient.</p>
<p>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. This is generally</p>
<p>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 addressing
is the default mode of operation on any PCI-bus configuration; use
<code>"nolinear"</code> to disable it.
For other bus types, it is generally
possible on 543x local bus cards, and if you have less than 16Mb of system
memory, on local bus 542x cards and ISA 543x cards. You must specify
the <code>"linear"</code> option and possibly a <code>Membase</code>
address. See the following sections for a detailed description.</p>
<p>Memory-mapped I/O is the default mode of operation for any Alpine family
chip. For the 5429, the <code>"mmio"</code> option may be used
to enable it, but it has not been tested.</p>
<p>Finally, if you have 546X chip, it will be on either a PCI or AGP bus.
As such, there
is no problem about memory mapped I/O or linear frame buffer address spaces
running into system memory.  The PCI spaces are mapped way up near the 4GB
point.  Because the mmio and linear frame buffer don't conflict at all on 
the system, the <code>"linear"</code>, <code>Membase</code>, and 
<code>"mmio"</code> options are ignored (memory mapped I/O  and linear
addressing are always used).</p>

 <HR NOSHADE>
<A HREF="cirrus.html"><EM> Information for Cirrus Chipset Users</EM></A>
 <b>:</b> <EM>Basic configuration </EM><BR>
<b>Previous:</b> <A HREF="cirrus1.html"><EM>Supported chipsets </EM></A><BR>
<b>Next:</b> <A HREF="cirrus3.html"><EM>XF86Config options </EM></A>



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