The driver recognises a number of xorg.conf 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.
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.
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.
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.
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.
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.
For the purpose of specifying a clock line in your xorg.conf, 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''.
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 xorg.conf clock specification, and programme the clock generator as needed by the modes used during the X session.
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 xorg.conf 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).
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 accelerated servers.
If no clocks are specified in the xorg.conf, 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 xorg.conf to specify the actual values used by the adapter. Any more will be ignored.
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.
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.
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.
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.
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.
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.
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.
This option enables the driver's support for VESA's Display Power Management Specification.
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.
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.
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.
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.