ATI Adapters README file : XF86Config specifications
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## 5. XF86Config specifications

The driver recognises a number of XF86Config options. In general, all such options should be specified in a ``Device'' section, and affect only that ``Device'' section.

Those options that affect how the driver associates adapters with ``Device'' sections are described first. The driver will ignore (with a message) a ``Device'' section if the section cannot be associated with exactly one adapter in the system. Similarly, the driver will ignore, or disable, (with a message) any adapter that cannot be associated with exactly one ``Device'' section. Thus, these options will be required in those uncommon cases where such unique associations cannot automatically be made by the driver.

Other options affect the driver's operation once an adapter has been assigned to the ``Device'' section which contains them.

### 5.1. Driver ``ati''

The use of this specification is highly recommended if the ``Device'' section is to be recognised by the driver. In fact, it is almost (but not quite) mandatory, particularly when using the loader server as it indicates what driver is to be loaded and associated with the ``Device'' section.

### 5.2. ChipSet ``name''

The default ChipSet name for this driver is ``ati''. In this case, any ATI adapter can be associated with the ``Device'' section. If an ATI accelerator is detected and the driver supports it, the accelerator's CRTC will be used to drive the screen. Otherwise, the driver will programme the adapter's SuperVGA CRTC.

If ``ativga'' is specified instead, the driver will ignore any ATI accelerator it detects, but otherwise operate as if ``ati'' had been specified. This specification ensures the VGA CRTC is used.

A ChipSet name of ``ibmvga'' causes any VGA-capable adapter in the system to be associated with the ``Device'' section. It enables the driver's generic VGA support, but only for non-ATI adapters. If an ATI adapter is associated with the ``Device'' section, the driver will operate as if ``ativga'' had been specified instead.

A ChipSet name of ``vgawonder'' is equivalent to ``ativga'', except that only VGAWonder-capable adapters can be assigned to the ``Device'' section. This specifically excludes the newer integrated Mach64 controllers.

In some PCI or AGP systems, the driver will not, by default, probe for non-PCI Mach32's or Mach64's. This is because, before doing any such probe, the driver attempts to determine if the probe can cause a lockup. If the driver has enough information to determine that a lockup would occur, it will skip the probe. In some situations, this determination cannot be accurate, and the driver will err on the side of caution, skipping the probe. Specifying a ChipSet name of ``mach32'' or ``mach64'', as appropriate, will force the driver to probe for the non-PCI adapter. These ChipSet names should, therefore, only be used when there is in fact such an adapter in the system. They are otherwise equivalent to ``ati''.

On non-Intel platforms, only ``ati'' and ``mach64'' ChipSet values are operative.

### 5.3. ChipID & ChipRev specifications

These specifications will cause the driver to associate the ``Device'' section only with an adapter having the same attributes, or an adapter whose PCI device ID the driver does not recognise. In the second case, these options cause the driver to treat the adapter as if it was one with the specified PCI device ID or revision. ChipID can only be used with Mach32 or Mach64 adapters, and, thus, specifically excludes any other adapter from matching the ``Device'' section. ChipRev is meaningful only with Mach64 adapters, and then only if ChipID is also specified in the same ``Device'' section.

### 5.4. IOBase

This option limits the adapters that can be associated with the ``Device'' section to the one with the specified I/O base. This option only applies to Mach64 adapters and specifically excludes other adapters.

### 5.5. BusID

This option limits the adapters that can be associated with the ``Device'' section to the one with the specified PCI Bus ID. This specification excludes non-PCI adapters.

### 5.6. Clocks

For the purpose of specifying a clock line in your XF86Config, one of four different situations can occur, as follows.

Those configuring the driver's generic VGA support for a non-ATI adapter, can skip ahead to the ``Clocks for non-ATI adapters'' section below. Those not trying to configure the driver for a Mach64 adapter, can skip ahead to the ``Clocks for fixed clock generators on ATI adapters'' section below.

The very earliest Mach64 adapters use fixed (i.e. non-programmable) clock generators. Very few of these (mostly prototypes) are known to exist, but if you have one of these, you can also skip ahead to the ``Clocks for fixed clock generators on ATI adapters'' section below.

The two cases that are left deal with programmable clock generators, which are used on the great majority of Mach64 adapters.

If you are uncertain which situation applies to your adapter, you can run a clock probe with the command ```X -probeonly`''.

#### 5.6.1. Clocks for supported programmable clock generators

At bootup, video BIOS initialisation 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 (e.g. MS-Windows, AutoCAD, X, etc.). The clock numbers reserved in this way are dependent on the particular clock generator used by the adapter.

The driver currently supports all programmable clock generators known to exist on Mach64 adapters. In this case, the driver will completely ignore any XF86Config clock specification, and programme the clock generator as needed by the modes used during the X session.

#### 5.6.2. Clocks for unsupported programmable clock generators

This case is unlikely to occur, but is documented for the sake of completeness.

In this situation, the driver will probe the adapter for clock frequencies unless XF86Config clocks are already specified. In either case, the driver will then attempt to normalise the clocks to one of the following specifications:

    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).

#### 5.6.3. Clocks for fixed clock generators on ATI adapters

This section applies to all VGAWonder and Mach32 adapters, and to early Mach64 prototypes.

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   0.000  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   0.000  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   0.000  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   0.000  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

    ICS 2494-AM clock generators (found on some Dell motherboards):

      Clocks  75.000  77.500  80.000  90.000  25.175  28.322  31.500  36.000
             100.000 110.000 126.000 135.000  40.000  44.900  50.000  65.000
              37.500  38.750  40.000  45.000  12.588  14.161  15.750  18.000
              50.000  55.000  63.000  67.500  20.000  22.450  25.000  32.500
              25.000  25.833  26.667  30.000   8.392   9.441  10.500  12.000
              33.333  36.667  42.000  45.000  13.333  14.767  16.667  21.667
              18.750  19.375  20.000  22.500   6.294   7.081   7.875   9.000
              25.000  27.500  31.500  33.750  10.000  11.225  12.500  16.250

VGAWonder VLB, VGA 1024 VLB, Mach32 and Mach64 owners should only specify up to the first 32 frequencies. Any more will be ignored.

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 specified 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 previous XFree86 accelerated servers.

#### 5.6.4. Clocks for non-ATI adapters

If no clocks are specified in the XF86Config, the driver will probe for four clocks, the second of which will be assumed to be 28.322 MHz. The first clock will typically be 25.175 MHz, but there are exceptions. You can include up to four clock frequencies in your XF86Config to specify the actual values used by the adapter. Any more will be ignored.

### 5.7. Option ``nopanel_display''

This specification is only effective when the driver detects that the adapter's BIOS has initialised both the digital flat panel and CRT interfaces. In such a situation, the driver will normally drive both the panel and the CRT. This specification causes the driver to disable the digital flat panel and display the screen image on the CRT instead, which could potentially allow for larger physical resolutions than the panel can handle.

### 5.8. Option ``crt_display''

This specification is only effective when the driver detects that the adapter's BIOS has initialised the digital flat panel interface, but has disabled the CRT interface. In such a situation the driver will normally drive only the panel. This specification causes the driver to instead display the same image on both the panel and the CRT.

### 5.9. Option ``noaccel''

By default, the driver will accelerate draw operations if a Mach64 CRTC is used to drive the display. As implemented in this driver, acceleration does not require a linear video memory aperture. This option disables this acceleration.

### 5.10. Option ``nolinear''

By default, the driver will enable a linear video memory aperture for 256-colour and higher depth modes if it is also using a Mach64 accelerator CRTC or an integrated Mach64 graphics chip. This option disables this linear aperture.

On non-Intel platforms, the driver requires a linear aperture and, so, this option is ignored.

### 5.11. Option ``HWCursor'' and Option ``SWCursor''

Option ``HWCursor'', which is the default, specifies that hardware facilities are to be used to paint the mouse pointer on the screen. Option ``SWCursor'' specifies that the mouse pointer is to be drawn by software, which is much slower. If both options are specified, option ``SWCursor'' prevails. Currently, these options are only acted upon for 256-colour or higher depth modes, if a Mach64 accelerator CRTC, or a Mach64 integrated controller is being used. In all other situations, a software cursor will be used, regardless of what these options specify.

### 5.12. Option ``SilkenMouse''

This option is only acted upon when a hardware cursor is being used. It specifies that the cursor's position on the screen is to be updated as quickly as possible when the mouse is moved. This is the default behaviour. If this option is negated, the cursor may lag the mouse when the X server is very busy.

### 5.13. Option ``shadowfb''

If this option is enabled, the driver will cause the CPU to do each drawing operation first into a shadow frame buffer in system virtual memory and then copy the result into video memory. If this option is not active, the CPU will draw directly into video memory. Enabling this option is beneficial for those systems where reading from video memory is, on average, slower than the corresponding read/modify/write operation in system virtual memory. This is normally the case for PCI or AGP adapters, and, so, this option is enabled by default. For other bus types, the default behaviour is to disable this option.

Note that, due to various limitations, this option is forcibly disabled when a linear video memory aperture is not enabled, when the frame buffer depth is less than 8, or when acceleration is used.

### 5.14. Option ``dpms''

This option enables the driver's support for VESA's Display Power Management Specification.

### 5.15. Option ``backingstore''

This is not specifically a driver option. It is used to enable the server's support for backing store, a mechanism by which pixel data for occluded window regions is remembered by the server thereby alleviating the need to send expose events to X clients when the data needs to be redisplayed.

### 5.16. MemBase address

This specification is only effective for non-PCI Mach64 adapters, and is used to override the CPU address at which the adapter will map its video memory. Normally, for non-PCI adapters, this address is set by a DOS install utility provided with the adapter. The MemBase option can also be used to enable the linear aperture in those cases where ATI's utility was not, or can not be, used.

For PCI and AGP adapters, this address is determined at system bootup according to the PCI Plug'n'Play specification which arbitrates the resource requirements of most devices in the system. This means the driver can not easily change the linear aperture address.

### 5.17. Option ``ReferenceClock'' ``frequency''

This option is only applicable to non-Intel platforms, where an adapter BIOS is not available to the driver. The option specifies the reference frequency used by the adapter's clock generator. The default is 14.318 MHz, and other typical values are 28.636, or 29.5 MHz.

### 5.18. ClockChip ``name''

This option is only applicable to non-Intel platforms, where an adapter BIOS is not available to the driver, and the driver cannot reliably determine whether the clock generator the adapter uses is a variant of an ATI 18818 (a.k.a. ICS 2595) or an unsupported clock generator. The only values that are acted upon are ``ATI 18818-0'' or ``ATI 18818-1''. From this specification, the driver derives a reference divider of 43 or 46 (respectively) for use in clock programming calculations. The driver's default behaviour, in this case, is to assume an unsupported clock generator, which means it will treat it as a fixed-frequency clock generator, as described under the heading ``Clocks for unsupported programmable clock generators'' above.

ATI Adapters README file : XF86Config specifications
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