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svgalib.chips(7)              Svgalib User Manual             svgalib.chips(7)

NAME
       svgalib.chips - Information for Chips and Technologies Users

TABLE OF CONTENTS
       Information for Chips and Technologies Users
       David Bateman <[email protected]>
       23nd May 1997

       0. Introduction
       1. "libvga.config" options
       2. Unsupported Chips and Technologies chipsets
       3. Known bugs

0. INTRODUCTION
       This is the really only my first attempt to get a working fully
       featured driver for the Chips and Technologies chipset to work with
       svgalib(7).  As such the only machine that I know it will work on is my
       own. If you use this software then at this point I'm still very
       interested in hearing from you by e-mail. Include full details of your
       chipset, amount of videoram and whether you have a VL-Bus or PCI bus
       machine.

       This server was written using the svgalib(7) patch from Sergio and
       Angelo Masci as a starting point. This version of the code resembled
       the XFree server code that was used up to XFree 3.1.2. As such it was
       incapable of programming the clocks, using linear addressing, Hi-Color,
       True-Color modes or the hardware acceleration. All of these features
       have since been added to the code. In addition support for the 65525,
       65535, 65546, 65548, 65550 and 65554 have been included. The 64200 and
       64300 chips are unsupported, however these chips are very similar to
       the 6554x chips which are supported.

       At this point this code is only confirmed to work correctly on a 65545
       VL-Bus machine. However as much of the code was stolen from my
       experiences with writing code for XFree I hope not to have too many
       problems with other machines. However if you run this code on a
       65545/48 PCI machine or a 65550/54 machine then I am particularly
       interested in hearing of any success or failure stories.

1. "libvga.config" OPTIONS
       The first thing to note is that the option parser for svgalib(7) is not
       very robust. Hence if you make some typing mistakes, you can have some
       very strange effects. I've set out below the libvga.config(5) options
       that are of particular interest to Chips and Technologies users.
       Normally this configuration file can be found at
       /etc/vga/libvga.config.

       HorizSync MIN MAX
              Often LCD panels has very different specifications for the
              horizontal sync than CRT's do. Hence often you'll need this
              option, particularly if you are using the XFree like modelines
              described below. The two floating point numbers specified will
              set the minimum and maximum allowed horizontal sync in kHz.

       VertRefresh MIN MAX
              Similar to the above, but this sets the LCD or CRT's vertical
              refresh rate in Hz.

       modeline 640x480 20.00 640 688 704 776 480 480 481 486
              This option allows you to specify XFree like modelines to use in
              preference to the in built modelines. Often LCD panels will need
              very different pixel clocks and timings than CRT's. Hence this
              option allows you to specify these. Note that the LCD panel
              timings are related to the panel size and not the mode size.
              Therefore by default the BIOS setting already uploaded into the
              registers are used by default. See the "UseModeline" option
              below if you wish to override these.

       chipset C&T 5 1024
              These option allows the user to specify the chipset to use and
              the amount of installed memory in kBytes. Currently supported
              chipsets are

                           0    65520
                           1    65525
                           2    65530
                           3    65535
                           4    65540
                           5    65545
                           6    65546
                           7    65548
                           8    65550
                           9    65554

       TextClockFreq 25.175
              One major difference between this code and the previously
              available support for the Chips and Technologies chipsets is
              that it supports the use of programmable clocks. Because of the
              way that the Chips and Technologies chips program the VCO from
              the registers, there is no way to be sure to recover the
              previously programmed clock value.  Hence the driver assumes
              that the console clock is 25.175MHz. This will be wrong for many
              machines. However I have supplied this option to use a different
              value that might be more suitable for your machine.

       nolinear
              This option disables the use of the linear framebuffer. This
              might be useful for machines that have broken linear
              framebuffers.

       linear Allow, but don't enforce the use of the linear framebuffer. As
              this is the default anyway, I don't see that this option is much
              use.

       setuplinear 0xC0000000
              For VL-Bus machines I expect that the linear framebuffer
              starting address will be setup correctly. However to get the
              starting address for PCI machines requires access to the MEMBASE
              register in the PCI address space. Code to do this doesn't
              currently exist with svgalib(7), and so I've taken the easy
              option of just testing a few known PCI starting addresses. For
              now these are just 0xFE000000, 0xFD000000, 0x41000000 and
              0xC0000000. If you have a different starting address then the
              linear framebuffer will be unusable. You might like to report
              your starting address to me so that I can include it in the
              probing code, but till then this option can be used to set up
              the correct address. This option just forces the given address
              to be the only one probed. It doesn't force the linear
              framebuffer to be used.

       LCDPanelSize 800 600
              For some machines the LCD panel size is incorrectly probed from
              the registers. This option forces the LCD panel size to be as
              specified. If you have a black band down one side of your LCD
              display you might very well need this option. Also if you are
              using the option "fix_panel_size" in XFree then this option has
              a similar effect. This option can be used in conjunction with
              the option "UseModeline" to program all the panel timings using
              the modeline values. Two machines that are known to need this
              option are the HP Omnibook 5000CTS and the NEC Versa 4080
              800x600 TFT machines.

       UseModeline
              The flat panel timings are related to the panel size and not the
              size of the mode specified. For this reason the default
              behaviour of the svgalib(7) is to use the panel timings already
              installed in the chip. The user can force the panel timings to
              be recalculated from the modeline with this option. However the
              panel size will still be probed. Two machines that are known to
              need this option are the HP Omnibook 5000CTS and the Prostar
              8200. You are advised to check the README.chips that come with
              XFree for more details.

       NoBitBlt
              This option disables the use of H/W acceleration. As far as I
              know the only thing that currently uses the H/W acceleration is
              libvgagl, so this might not be a problem anyway. However if you
              see corruption of the graphics on the screen try this option and
              see if it goes away.

       Use18BitBus
              For 24bpp on TFT screens, the server assumes that a 24bit bus is
              being used. This can result in a reddish tint to 24bpp mode for
              machines that actually have a 18 bit bus. This option, selects
              an 18 bit TFT bus. Note that using this option with a 24 bit bus
              machine will similarly discolour the screen. For other depths
              this option has no effect.

       Center ENABLE/DISABLE or Stretch ENABLE/DISABLE
              The default behaviour of svgalib(7) is to leave the stretching
              and centring registers completely alone. However for some
              machines this might result in poorly placed modes, or modes that
              don't fill the whole screen. These two options can be used to
              centre and stretch the mode on the screen. Note that for
              instance a Center DISABLE might follow a Center ENABLE in the
              config file. Only the last option takes effect.

2. UNSUPPORTED CHIPS AND TECHNOLOGIES CHIPSETS
       The 64200 and 64300 chips are unsupported. However by specifying the
       chipset in your libvga.config as either a

       chipset C&T 3 2048
              Use 65535 for a 64200 assuming 2M of video ram, or

       chipset C&T 7 2048
              Use 65548 for a 64300 assuming 2Mb of video ram

       then svgalib can be made to give limited support to these chipsets.
       Note that the paged addressing mode of the 65548 chip and earlier can
       only address upto 1Mb of video ram. If the additional memory is needed
       then linear addressing must be used!! Note that support of the 64xxx
       chips has not been tested at all, and the above is just a suggestion
       that I believe will work.

3. KNOWN BUGS
       One persistent and annoying bug is that the text mode stretching on LCD
       displays is not always restored correctly for 65550 and 65554 machines.
       This is to do with the manner in which the extended registers are
       restored and what is being done with the synchronous reset while the
       registers are restored. As I don't have a 65550 or 65554 machine of my
       own on which to test this code, I have been unable to fix this problem.
       In most circumstances an LCD-CRT switch will restore the LCD stretching
       to the desired state.

       David.

FILES
       /etc/vga/libvga.config

SEE ALSO
       svgalib(7), libvga.config(5).

AUTHOR
       of the driver and this documentation is David Bateman
       <[email protected]>.  However, it was slightly reformatted by
       Michael Weller <[email protected]>.

Svgalib (>= 1.2.11)              31 July 1997                 svgalib.chips(7)
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