What should I put in my XF86Config file?

ATI adapters README : What should I put in my XF86Config file?
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## 4. What should I put in my XF86Config file?

The chipset will be automatically detected. The chipset name for this driver is "ati". The driver also recognizes "vgawonder", "mach8", "mach32" and "mach64" as chipset names. In this version of the driver, all names are equivalent. In some future version each name will have a different meaning to be documented at that time.

The clocks line to be specified in your XF86Config depends on what the adapter uses to generate dot clocks.

For all adapters, one of the following clocks specifications (or an initial subset thereof) can be used depending on what the adapter uses to generate dot clocks:

    Crystals (VGA Wonder V3 and V4 adapters only):

      Clocks  50.000  56.644   0.000  44.900  44.900  50.000   0.000  36.000
              25.000  28.322   0.000  22.450  22.450  25.000   0.000  18.000
              16.667  18.881   0.000  14.967  14.967  16.667   0.000  12.000
              12.500  14.161   0.000  11.225  11.225  12.500   0.000   9.000

    ATI 18810 clock generator:

      Clocks  30.240  32.000  37.500  39.000  42.954  48.771   0.000  36.000
              40.000  56.644  75.000  65.000  50.350  56.640   0.000  44.900
              15.120  16.000  18.750  19.500  21.477  24.386   0.000  18.000
              20.000  28.322  37.500  32.500  25.175  28.320   0.000  22.450
              10.080  10.667  12.500  13.000  14.318  16.257   0.000  12.000
              13.333  18.881  25.000  21.667  16.783  18.880   0.000  14.967
               7.560   8.000   9.375   9.750  10.739  12.193   0.000   9.000
              10.000  14.161  18.750  16.250  12.586  14.160   0.000  11.225

    ATI 18811-0 and ATI 18812-0 clock generators:

      Clocks  30.240  32.000 110.000  80.000  42.954  48.771  92.400  36.000
              39.910  44.900  75.000  65.000  50.350  56.640   0.000  44.900
              15.120  16.000  55.000  40.000  21.477  24.386  46.200  18.000
              19.955  22.450  37.500  32.500  25.175  28.320   0.000  22.450
              10.080  10.667  36.667  26.667  14.318  16.257  30.800  12.000
              13.303  14.967  25.000  21.667  16.783  18.880   0.000  14.967
               7.560   8.000  27.500  20.000  10.739  12.193  23.100   9.000
               9.978  11.225  18.750  16.250  12.588  14.160   0.000  11.225

    ATI 18811-1 and ATI 18811-2 clock generators:

      Clocks 135.000  32.000 110.000  80.000 100.000 126.000  92.400  36.000
              39.910  44.900  75.000  65.000  50.350  56.640   0.000  44.900
              67.500  16.000  55.000  40.000  50.000  63.000  46.200  18.000
              19.955  22.450  37.500  32.500  25.175  28.320   0.000  22.450
              45.000  10.667  36.667  26.667  33.333  42.000  30.800  12.000
              13.303  14.967  25.000  21.667  16.783  18.880   0.000  14.967
              33.750   8.000  27.500  20.000  25.000  31.500  23.100   9.000
               9.978  11.225  18.750  16.250  12.588  14.160   0.000  11.225

Mach32 and Mach64 owners should only specify up to the first 32 frequencies.

The oldest Mach64 adapters use one of the clock generators described above. The possibilities for Mach64 adapters also include programmable clock generators. At bootup, video BIOS initialization programmes an initial set of frequencies. Two of these are reserved to allow the setting of modes that do not use a frequency from this initial set. One of these reserved slots is used by the BIOS mode set routine, the other by the particular driver used (MS-Windows, AutoCAD, X, etc.). The clock numbers reserved in this way are dependent on the particular clock generator used on the adapter.

If the driver does not support the adapter's clock generator, it will try to match the clocks to one of the following specifications. This matching will occur whether or not the user specifies the clocks in XF86Config.

    BIOS setting 1:

      Clocks   0.000 110.000 126.000 135.000  50.350  56.640  63.000  72.000
               0.000  80.000  75.000  65.000  40.000  44.900  49.500  50.000
               0.000  55.000  63.000  67.500  25.180  28.320  31.500  36.000
               0.000  40.000  37.500  32.500  20.000  22.450  24.750  25.000

    BIOS setting 2:

      Clocks   0.000 110.000 126.000 135.000  25.180  28.320  31.500  36.000
               0.000  80.000  75.000  65.000  40.000  44.900  49.500  50.000
               0.000  55.000  63.000  67.500  12.590  14.160  15.750  18.000
               0.000  40.000  37.500  32.500  20.000  22.450  24.750  25.000

    BIOS setting 3:

      Clocks   0.000   0.000   0.000   0.000  25.180  28.320   0.000   0.000
               0.000   0.000   0.000   0.000   0.000   0.000   0.000   0.000
               0.000   0.000   0.000   0.000  12.590  14.160   0.000   0.000
               0.000   0.000   0.000   0.000   0.000   0.000   0.000   0.000

If the driver matches the clocks to the third setting above, functionality will be *extremely* limited (assuming the driver works at all).

Other clock generators that have been used on ATI adapters (which can all be said to be clones of one of the above) might generate non-zero frequencies for those that are zero above, or vice-versa.

The order of the clocks *is* very important, although the driver will reorder the clocks if it deems it appropriate to do so. Mach32 and Mach64 owners should note that this order is different than what they would use for the accelerated servers.

If the driver detects a supported programmable clock generator, it will ignore any XF86Config clock specification and programme the generator as needed by the modes to be used during the X session.

A clock probe, done with the command "X -probeonly", will help you decide which of the above to use for your particular adapter. If the server consistently reports that it has detected an unknown clock generator, please e-mail me the stderr output.

Modes can be derived from the information in XFree86's doc directory. If you do not specify a "modes" line in the display subsection of the appropriate screen section of your XF86Config, the driver will generate a default mode and attempt to use it. The timings for the default mode are derived from the timings of the mode (usually a text mode) in effect when the server is started.

ATI adapters README : What should I put in my XF86Config file?
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