Information for Chips and Technologies Users
David Bateman ( <mailto:dbateman@club-internet.fr>), Egbert
Eich ( <mailto:eich@freedesktop.org>)
1st January 2001
____________________________________________________________
Table of Contents
1. Introduction
2. Supported Chips
2.1 Basic architecture
2.2 WinGine architecture
2.3 HiQV Architecture
3. xorg.conf Options
4. Modelines
5. Dual Display Channel
6. The Full Story on Clock Limitations
7. Troubleshooting
8. Disclaimer
9. Acknowledgement
10. Authors
______________________________________________________________________
1. Introduction
The Chips and Technologies driver release in X11R7.5 came from XFree86
4.4 rc2; this document was originally included in that release and has
been updated modestly to reflect differences between X11R7.5 and
XFree86 4.4 rc2.
With the release of XFree86 version 4.0, the Chips and Technologies
driver has been extensively rewritten and contains many new features.
This driver must be considered work in progress, and those users
wanting stability are encouraged to use the older XFree86 3.3.x
versions. However this version of the Chips and Technologies driver
has many new features and bug fixes that might make users prefer to
use this version. These features include
o The long standing black/blue screen problem that some people have
had should be fixed.
o Hardware/Software cursor switching on the fly, that should fix many
of the known hardware cursor problems.
o Gamma correction at all depths and DirectColor visuals for depths
of 15 or greater with the HiQV series of chipsets.
o Supports PseudoColor overlays on 16bpp TrueColor screens for HiQV.
o Supports YUV colour space conversion with the XVideo extension.
o 32bpp pixmaps while using a framebuffer in 24bpp packed pixel mode.
o Heaps more acceleration.
o 1/4bpp support.
o Multihead
o Much more...
This document attempts to discuss the features of this driver, the
options useful in configuring it and the known problems. Most of the
Chips and Technologies chipsets are supported by this driver to some
degree.
2. Supported Chips
The Chips and Technologies chipsets supported by this driver have one
of three basic architectures. A basic architecture, the WinGine
architecture which is a modification on this basic architecture and a
completely new HiQV architecture.
2.1. Basic architecture
ct65520
(Max Ram: 1Mb, Max Dclk: 68MHz@5V)
ct65525
This chip is basically identical to the 65530. It has the same
ID and is identified as a 65530 when probed. See ct65530 for
details.
ct65530
This is a very similar chip to the 65520. However it
additionally has the ability for mixed 5V and 3.3V operation and
linear addressing of the video memory. (Max Ram: 1Mb, Max Dclk:
56MHz@3.3V, 68MHz@5V)
ct65535
This is the first chip of the ct655xx series to support fully
programmable clocks. Otherwise it has the the same properties as
the 65530.
ct65540
This is the first version of the of the ct655xx that was capable
of supporting Hi-Color and True-Color. It also includes a fully
programmable dot clock and supports all types of flat panels.
(Max Ram: 1Mb, Max Dclk: 56MHz@3.3V, 68MHz@5V)
ct65545
The chip is very similar to the 65540, with the addition of H/W
cursor, pop-menu acceleration, BitBLT and support of PCI Buses.
PCI version also allow all the BitBLT and H/W cursor registers
to be memory mapped 2Mb above the Base Address. (Max Ram: 1Mb,
Max Dclk: 56MHz@3.3V,68MHz@5V)
ct65546
This chip is specially manufactured for Toshiba, and so
documentation is not widely available. It is believed that this
is really just a 65545 with a higher maximum dot-clock of 80MHz.
(Max Ram: 1Mb?, Max Dclk: 80MHz?)
ct65548
This chip is similar to the 65545, but it also includes XRAM
support and supports the higher dot clocks of the 65546. (Max
Ram: 1Mb, Max Dclk: 80MHz)
2.2. WinGine architecture
ct64200
This chip, also known as the WinGine, is used in video cards for
desktop systems. It often uses external DAC's and programmable
clock chips to supply additional functionally. None of these are
currently supported within the driver itself, so many cards will
only have limited support. Linear addressing is not supported
for this card in the driver. (Max Ram: 2Mb, Max Dclk: 80MHz)
ct64300
This is a more advanced version of the WinGine chip, with
specification very similar to the 6554x series of chips. However
there are many differences at a register level. A similar level
of acceleration to the 65545 is included for this driver. (Max
Ram: 2Mb, Max Dclk: 80MHz)
2.3. HiQV Architecture
ct65550
This chip includes many new features, including improved BitBLT
support (24bpp colour expansion, wider maximum pitch, etc),
Multimedia unit (video capture, zoom video port, etc) and 24bpp
uncompressed true colour (i.e 32bpp mode). Also memory mapped
I/O is possible on all bus configurations. (Max Ram: 2Mb, Max
Dclk: 80MHz@3.3V,100MHz@5V)
ct65554
This chip is similar to the 65550 but has a 64bit memory bus as
opposed to a 32bit bus. It also has higher limits on the maximum
memory and pixel clocks (Max Ram: 4Mb, Max Dclk: 100MHz@3.3V)
ct65555
Similar to the 65554 but has yet higher maximum memory and pixel
clocks. It also includes a new DSTN dithering scheme that
improves the performance of DSTN screens. (Max Ram: 4Mb, Max
Dclk: 110MHz@3.3V)
ct68554
Similar to the 65555 but also incorporates "PanelLink" drivers.
This serial link allows an LCD screens to be located up to 100m
from the video processor. Expect to see this chip soon in LCD
desktop machines (Max Ram: 4Mb, Max Dclk: 110MHz@3.3V)
ct69000
Similar to the 65555 but incorporates 2Mbytes of SGRAM on chip.
It is the first Chips and Technologies chipset where all of the
registers are accessible through MMIO, rather than just the
BitBlt registers. (Max Ram: 2Mb Only, Max Dclk: 130MHz@3.3V)
ct69030
Similar to the 69000 but incorporates 4Mbytes of SGRAM on chip
and has faster memory and pixel clock limits. Also includes a
second display channel so that the CRT can display independently
of the LCD. (Max Ram: 4Mb Only, Max Dclk: 170MHz@3.3V)
3. xorg.conf Options
The following options are of particular interest to the Chips and
Technologies driver. It should be noted that the options are case
insensitive, and that white space and "_" characters are ignored.
There are therefore a wide variety of possible forms for all options.
The forms given below are the preferred forms.
Options related to drivers can be present in the Screen, Device and
Monitor sections and the Display subsections. The order of precedence
is Display, Screen, Monitor, Device.
Option
This option will disable the use of any accelerated functions.
This is likely to help with some problems related to DRAM
timing, high dot clocks, and bugs in accelerated functions, at
the cost of performance (which will still be reasonable on
VLB/PCI).
VideoRam 1024 (or another value)
This option will override the detected amount of video memory,
and pretend the given amount of memory is present on the card.
Option
By default linear addressing is used on all chips where it can
be set up automatically. The exception is for depths of 1 or
4bpp where linear addressing is turned off by default. It is
possible to turn the linear addressing off with this option.
Note that H/W acceleration is only supported with linear
addressing.
Option
When the chipset is capable of linear addressing and it has been
turned off by default, this option can be used to turn it back
on. This is useful for the 65530 chipset where the base address
of the linear framebuffer must be supplied by the user, or at
depths 1 and 4bpp. Note that linear addressing at 1 and 4bpp is
not guaranteed to work correctly.
MemBase 0x03b00000 (or a different address)
This sets the physical memory base address of the linear
framebuffer. Typically this is probed correctly, but if you
believe it to be mis-probed, this option might help. Also for
non PCI machines specifying this force the linear base address
to be this value, reprogramming the video processor to suit.
Note that for the 65530 this is required as the base address
can't be correctly probed.
Option
For chipsets that support hardware cursors, this option enforces
their use, even for cases that are known to cause problems on
some machines. Note that it is overridden by the "SWcursor"
option. Hardware cursors effectively speeds all graphics
operations as the job of ensuring that the cursor remains on top
is now given to the hardware. It also reduces the effect of
cursor flashing during graphics operations.
Option
This disables use of the hardware cursor provided by the chip.
Try this if the cursor seems to have problems.
Option
The server is unable to differentiate between SS STN and TFT
displays. This forces it to identify the display as a SS STN
rather than a TFT.
Option
The flat panel timings are related to the panel size and not the
size of the mode specified in xorg.conf. For this reason the
default behaviour of the server 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.
Option
For some machines the LCD panel size is incorrectly probed from
the registers. This option forces the LCD panel size to be
overridden by the modeline display sizes. This will prevent the
use of a mode that is a different size than the panel. Before
using this check that the server reports an incorrect panel
size. This option can be used in conjunction with the option
"UseModeline" to program all the panel timings using the
modeline values.
Option
When the size of the mode used is less than the panel size, the
default behaviour of the server is to stretch the mode in an
attempt to fill the screen. A "letterbox" effect with no
stretching can be achieved using this option.
Option
When the size of the mode used is less than the panel size, the
default behaviour of the server is to align the left hand edge
of the display with the left hand edge of the screen. Using this
option the mode can be centered in the screen. This option is
reported to have problems with some machines at 16/24/32bpp, the
effect of which is that the right-hand edge of the mode will be
pushed off the screen.
Option
For the chips either using the WinGine or basic architectures,
the chips generates a number of fixed clocks internally. With
the chips 65535 and later or the 64300, the default is to use
the programmable clock for all clocks. It is possible to use the
fixed clocks supported by the chip instead by using this option.
Typically this will give you some or all of the clocks 25.175,
28.322, 31.000 and 36.000MHz. The current programmable clock
will be given as the last clock in the list. On a cold-booted
system this might be the appropriate value to use at the text
console (see the "TextClockFreq" option), as many flat panels
will need a dot clock different than the default to synchronise.
The programmable clock makes this option obsolete and so it's
use isn't recommended. It is completely ignored for HiQV
chipsets.
TextClockFreq 25.175
Except for the HiQV chipsets, it is impossible for the server to
read the value of the currently used frequency for the text
console when using programmable clocks. Therefore the server
uses a default value of 25.175MHz as the text console clock. For
some LCDs, in particular DSTN screens, this clock will be wrong.
This allows the user to select a different clock for the server
to use when returning to the text console.
Option
Option "FPClock16" "65.0MHz" Option "FPClock24" "65.0MHz" Option
"FPClock32" "65.0MHz"" In general the LCD panel clock should be
set independently of the modelines supplied. Normally the chips
BIOS set the flat panel clock correctly and so the default
behaviour with HiQV chipset is to leave the flat panel clock
alone, or force it to be 90% of the maximum allowable clock if
the current panel clock exceeds the dotclock limitation due to a
depth change. This option allows the user to force the server
the reprogram the flat panel clock independently of the modeline
with HiQV chipset. The four options are for 8bpp or less, 16, 24
or 32bpp LCD panel clocks, where the options above set the
clocks to 65MHz.
Option
Option "FPClkIndx" "1"" The HiQV series of chips have three
programmable clocks. The first two are usually loaded with
25.175 and 28.322MHz for VGA backward compatibility, and the
third is used as a fully programmable clock. On at least one
system (the Inside 686 LCD/S single board computer) the third
clock is unusable. These options can be used to force a
particular clock index to be used
Option
This has a different effect depending on the hardware on which
it is used. For the 6554x machines MMIO is only used to talk to
the BitBLT engine and is only usable with PCI buses. It is
enabled by default for 65545 machines since the blitter can not
be used otherwise. The HiQV series of chipsets must use MMIO
with their BitBLT engines, and so this is enabled by default.
Option
The 690xx chipsets can use MMIO for all communications with the
video processor. So using this option on a 690xx chipset forces
them to use MMIO for all communications. This only makes sense
when the 690xx is on a PCI bus so that normal PIO can be
disabled.
Option
This option sets the centering and stretching to the BIOS
default values. This can fix suspend/resume problems on some
machines. It overrides the options "LcdCenter" and "NoStretch".
Option 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. This option, selects
an 18 bit TFT bus. For other depths this option
has no effect.
Chipset It is possible that the chip could be
misidentified, particular due to interactions
with other drivers in the server. It is possible
to force the server to identify a particular chip
with this option.
Option Composite sync on green. Possibly useful if you
wish to use an old workstation monitor. The HiQV
internal RAMDAC's supports this mode of
operation, but whether a particular machine does
depends on the manufacturer.
DacSpeed 80.000 The server will limit the maximum dotclock to a
value as specified by the manufacturer. This
might make certain modes impossible to obtain
with a reasonable refresh rate. Using this option
the user can override the maximum dot-clock and
specify any value they prefer. Use caution with
this option, as driving the video processor
beyond its specifications might cause damage.
Option Option "SetMClk" "38000kHz"" This option sets the
internal memory clock (MCLK) registers of HiQV
chipsets to 38MHz or some other value. Use
caution as excess heat generated by the video
processor if its specifications are exceeded
might cause damage. However careful use of this
option might boost performance. This option might
also be used to reduce the speed of the memory
clock to preserve power in modes that don't need
the full speed of the memory to work correctly.
This option might also be needed to reduce the
speed of the memory clock with the "Overlay"
option.
Option By default it is assumed that there are 6
significant bits in the RGB representation of the
colours in 4bpp and above. If the colours seem
darker than they should be, perhaps your ramdac
is has 8 significant bits. This option forces the
server to assume that there are 8 significant
bits.
Option This is a debugging option and general users have
no need of it. Using this option, when the
virtual desktop is scrolled away from the zero
position, the pixmap cache becomes visible. This
is useful to see that pixmaps, tiles, etc have
been properly cached.
Option This option is only useful when acceleration
can't be used and linear addressing can be used.
With this option all of the graphics are rendered
into a copy of the framebuffer that is keep in
the main memory of the computer, and the screen
is updated from this copy. In this way the
expensive operation of reading back to contents
of the screen is never performed and the
performance is improved. Because the rendering is
all done into a virtual framebuffer acceleration
can not be used.
Option The new TMED DSTN dithering scheme available on
recent HiQV chipsets gives improved performance.
However, some machines appear to have this
feature incorrectly setup. If you have snow on
your DSTN LCD, try using this option. This option
is only relevant for chipsets more recent than
the ct65555 and only when used with a DSTN LCD.
Option The HiQV chipsets contain a multimedia engine
that allow a 16bpp window to be overlayed on the
screen. This driver uses this capability to
include a 16bpp framebuffer on top of an 8bpp
framebuffer. In this way PseudoColor and
TrueColor visuals can be used on the same screen.
XFree86 believes that the 8bpp framebuffer is
overlayed on the 16bpp framebuffer. Therefore to
use this option the server must be started in
either 15 or 16bpp depth. Also the maximum size
of the desktop with this option is 1024x1024, as
this is the largest window that the HiQV
multimedia engine can display. Note that this
option using the multimedia engine to its limit,
and some manufacturers have set a default memory
clock that will cause pixel errors with this
option. If you get pixel error with this option
try using the "SetMClk" option to slow the memory
clock. It should also be noted that the XVideo
extension uses the same capabilities of the HiQV
chipsets as the Overlays. So using this option
disables the XVideo extension.
Option Normally the colour transparency key for the
overlay is the 8bpp lookup table entry 255. This
might cause troubles with some applications, and
so this option allows the colour transparency key
to be set to some other value. Legal values are 2
to 255 inclusive.
Option This sets the default pixel value for the YUV
video overlay key. Legal values for this key are
depth dependent. That is from 0 to 255 for 8bit
depth, 0 to 32,767 for 15bit depth, etc. This
option might be used if the default video overlay
key causes problems.
Option The 69030 chipset has independent display
channels, that can be configured to support
independent refresh rates on the flat panel and
on the CRT. The default behaviour is to have both
the flat panel and the CRT use the same display
channel and thus the same refresh rate. This
option forces the two display channels to be
used, giving independent refresh rates.
Option The ct69030 supports dual-head display. By
default the two display share equally the
available memory. This option forces the second
display to take a particular amount of memory.
Please read the section below about dual-head
display.
Option Option "XaaNoSolidFillRect", Option "XaaNoSolid-
HorVertLine", Option "XaaNoMono8x8PatternFill-
Rect", Option "XaaNoColor8x8PatternFillRect",
Option "XaaNoCPUToScreenColorExpandFill", Option
"XaaNoScreenToScreenColorExpandFill", Option
"XaaNoImageWriteRect", Option "XaaNoImageRead-
Rect", Option "XaaNoPixmapCache", Option
"XaaNoOffscreenPixmaps" " These option
individually disable the features of the XAA
acceleration code that the Chips and Technologies
driver uses. If you have a problem with the
acceleration and these options will allow you to
isolation the problem. This information will be
invaluable in debugging any problems.
4. Modelines
When constructing a modeline for use with the Chips and Technologies
driver you'll needed to considered several points
* Virtual Screen Size
It is the virtual screen size that determines the amount of
memory used by a mode. So if you have a virtual screen size set
to 1024x768 using a 800x600 at 8bpp, you use 768kB for the mode.
Further to this some of the XAA acceleration requires that the
display pitch is a multiple of 64 pixels. So the driver will
attempt to round-up the virtual X dimension to a multiple of 64,
but leave the virtual resolution untouched. This might further
reduce the available memory.
* 16/24/32 Bits Per Pixel
Hi-Color and True-Color modes are implemented in the server. The
clocks in the 6554x series of chips are internally divided by 2
for 16bpp and 3 for 24bpp, allowing one modeline to be used at
all depths. The effect of this is that the maximum dot clock
visible to the user is a half or a third of the value at 8bpp.
The HiQV series of chips doesn't need to use additional clock
cycles to display higher depths, and so the same modeline can be
used at all depths, without needing to divide the clocks. Also
16/24/32 bpp modes will need 2 , 3 or 4 times respectively more
video ram.
* Frame Acceleration
Many DSTN screens use frame acceleration to improve the
performance of the screen. This can be done by using an external
frame buffer, or incorporating the framebuffer at the top of
video ram depending on the particular implementation. The
Xserver assumes that the framebuffer, if used, will be at the
top of video ram. The amount of ram required for the
framebuffer will vary depending on the size of the screen, and
will reduce the amount of video ram available to the modes.
Typical values for the size of the framebuffer will be 61440
bytes (640x480 panel), 96000 bytes (800x600 panel) and 157287
bytes (1024x768 panel).
* H/W Acceleration
The H/W cursor will need 1kB for the 6554x and 4kb for the
65550. On the 64300 chips the H/W cursor is stored in registers
and so no allowance is needed for the H/W cursor. In addition to
this many graphics operations are speeded up using a "pixmap
cache". Leaving too little memory available for the cache will
only have a detrimental effect on the graphics performance.
* PseudoColor Overlay
If you use the "overlay" option, then there are actually two
framebuffers in the video memory. An 8bpp one and a 16bpp one.
The total memory requirements in this mode of operation is
therefore similar to a 24bpp mode. The overlay consumes memory
bandwidth, so that the maximum dotclock will be similar to a
24bpp mode.
* XVideo extension*
Like the overlays, the Xvideo extension uses a part of the video
memory for a second framebuffer. In this case enough memory
needs to be left for the largest unscaled video window that will
be displayed.
* VESA like modes
We recommend that you try and pick a mode that is similar to a
standard VESA mode. If you don't a suspend/resume or LCD/CRT
switch might mess up the screen. This is a problem with the
video BIOS not knowing about all the funny modes that might be
selected.
* Dot Clock
For LCD screens, the lowest clock that gives acceptable contrast
and flicker is usually the best one. This also gives more memory
bandwidth for use in the drawing operations. Some users prefer
to use clocks that are defined by their BIOS. This has the
advantage that the BIOS will probably restore the clock they
specified after a suspend/resume or LCD/CRT switch. For a
complete discussion on the dot clock limitations, see the next
section.
* Dual-head display
Dual-head display has two effects on the modelines. Firstly, the
memory requirements of both heads must fit in the available
memory. Secondly, the memory bandwidth of the video processor is
shared between the two heads. Hence the maximum dot-clock might
need to be limited.
The driver is capable of driving both a CRT and a flat panel display.
In fact the timing for the flat panel are dependent on the
specification of the panel itself and are independent of the
particular mode chosen. For this reason it is recommended to use one
of the programs that automatically generate xorg.conf files, such as
"xorgconfig".
However there are many older machines, particularly those with 800x600
screen or larger, that need to reprogram the panel timings. The reason
for this is that the manufacturer has used the panel timings to get a
standard EGA mode to work on flat panel, and these same timings don't
work for an SVGA mode. For these machines the "UseModeline" and/or
possibly the "FixPanelSize" option might be needed. Some machines that
are known to need these options include.
Modeline "640x480@8bpp" 25.175 640 672 728 816 480 489 501 526
Modeline "640x480@16bpp" 25.175 640 672 728 816 480 489 501 526
Options: "UseModeline"
Tested on a Prostar 8200, (640x480, 65548, 1Mbyte)
Modeline "800x600@8bpp" 28.322 800 808 848 936 600 600 604 628
Options: "FixPanelSize", "UseModeline"
Tested on a HP OmniBook 5000CTS (800x600 TFT, 65548, 1Mbyte)
Modeline "800x600@8bpp" 30.150 800 896 960 1056 600 600 604 628
Options: "FixPanelSize", "UseModeline"
Tested on a Zeos Meridan 850c (800x600 DSTN, 65545, 1Mbyte)
The IBM PC110 works best with a 15MHz clock (Thanks to Alan Cox):
Modeline "640x480" 15.00 640 672 728 816 480 489 496 526
Options: "TextClockFreq" "15.00"
IBM PC110 (65535, Citizen L6481L-FF DSTN)
The NEC Versa 4080 just needs the "FixPanelSize" option. To the best
of my knowledge no machine with a HiQV needs the "UseModeline" or
"FixPanelSize" options.
5. Dual Display Channel
XFree86 releases later than 4.1.0 and X.Org releases later than 6.7.0
support dual-channel display on the ct69030. This support can be used
to give a single display image on two screen with different refresh
rates, or entirely different images on the two displays.
Dual refresh rate display can be selected with the "DualRefresh"
option described above. However to use the dual-head support is
slightly more complex. Firstly, the ct69030 chipset must be installed
on a PCI bus. This is a driver limitation that might be relaxed in the
future. In addition the device, screen and layout sections of the
"xorg.conf" must be correctly configured. A sample of an incomplete
"xorg.conf" is given below
Section "Device"
Identifier "Chips and Technologies - Pipe A"
Driver "chips"
BusID "PCI:0:20:0"
Screen 0
EndSection
Section "Device"
Identifier "Chips and Technologies - Pipe B"
Driver "chips"
BusID "PCI:0:20:0"
Screen 1
EndSection
Section "Screen"
Identifier "Screen 0"
Device "Chips and Technologies - Pipe A"
Monitor "generic LCD"
SubSection "Display"
Depth 16
Modes "1024x768"
EndSubsection
EndSection
Section "Screen"
Identifier "Screen 1"
Device "Chips and Technologies - Pipe B"
Monitor "generic CRT"
SubSection "Display"
Depth 16
Modes "1024x768"
EndSubsection
EndSection
Section "ServerLayout"
Identifier "Main Layout"
Screen "Screen 0"
Screen "Screen 1" RightOf "Screen 0"
InputDevice "Mouse1" "CorePointer"
InputDevice "Keyboard1" "CoreKeyboard"
EndSection
The device section must include the PCI BusID. This can be found from
the log file of a working single-head installation. For instance, the
line
(--) PCI:*(0:20:0) C&T 69030 rev 97, Mem @ 0xed000000/24
appears for the case above. Additionally, the "Screen" option must
appear in the device section. It should be noted that if a flat panel
is used, this it must be allocated to "Screen 0".
The server can then be started with the "+xinerama" option as follows
startx -- +xinerama
For more information, read the Xinerama documentation.
It should be noted that the dual channel display options of the 69030
require the use of additional memory bandwidth, as each display
channel independently accesses the video memory. For this reason, the
maximum colour depth and resolution that can be supported in a dual
channel mode will be reduced compared to a single display channel
mode. However, as the driver does not prevent you from using a mode
that will exceed the memory bandwidth of the 69030, but a warning like
(WW) Memory bandwidth requirements exceeded by dual-channel
(WW) mode. Display might be corrupted!!!
If you see such display corruption, and you have this warning, your
choices are to reduce the refresh rate, colour depth or resolution, or
increase the speed of the memory clock with the the "SetMClk" option
described above. Note that increasing the memory clock also has its
own problems as described above.
6. The Full Story on Clock Limitations
There has been much confusion about exactly what the clock limitations
of the Chips and Technologies chipsets are. Hence I hope that this
section will clear up the misunderstandings.
In general there are two factors determining the maximum dotclock.
There is the limit of the maximum dotclock the video processor can
handle, and there is another limitation of the available memory
bandwidth. The memory bandwidth is determined by the clock used for
the video memory. For chipsets incapable of colour depths greater
that 8bpp like the 65535, the dotclock limit is solely determined by
the highest dotclock the video processor is capable of handling. So
this limit will be either 56MHz or 68MHz for the 655xx chipsets,
depending on what voltage they are driven with, or 80MHz for the 64200
WinGine machines.
The 6554x and 64300 WinGine chipsets are capable of colour depths of
16 or 24bpp. However there is no reliable way of probing the memory
clock used in these chipsets, and so a conservative limit must be
taken for the dotclock limit. In this case the driver divides the
video processors dotclock limitation by the number of bytes per pixel,
so that the limitations for the various colour depths are
8bpp 16bpp 24bpp
64300 85 42.5 28.33
65540/65545 3.3v 56 28 18.67
65540/65545 5v 68 34 22.67
65546/65548 80 40 26.67
For a CRT or TFT screen these limitations are conservative and the
user might safely override them with the "DacSpeed" option to some
extent. However these numbers take no account of the extra bandwidth
needed for DSTN screens.
For the HiQV series of chips, the memory clock can be successfully
probed. Hence you will see a line like
(--) CHIPS(0): Probed memory clock of 40.090 MHz
in your startx log file. Note that many chips are capable of higher
memory clocks than actually set by BIOS. You can use the "SetMClk"
option in your xorg.conf file to get a higher MClk. However some video
ram, particularly EDO, might not be fast enough to handle this,
resulting in drawing errors on the screen. The formula to determine
the maximum usable dotclock on the HiQV series of chips is
Max dotclock = min(MaxDClk, 0.70 * 8 * MemoryClk / (BytesPerPixel +
(isDSTN == TRUE ? 1 : 0)))
if you chips is a 69030 or 69000 or
Max dotclock = min(MaxDClk, 0.70 * 4 * MemoryClk / (BytesPerPixel +
(isDSTN == TRUE ? 1 : 0)))
otherwise. This effectively means that there are two limits on the
dotclock. One the overall maximum, and another due to the available
memory bandwidth of the chip. The 69030 and 69000 have a 64bit memory
bus and thus transfer 8 bytes every clock thus (hence the 8), while
the other HiQV chipsets are 32bit and transfer 4 bytes per clock cycle
(hence the 4). However, after accounting for the RAS/CAS signaling
only about 70% of the bandwidth is available. The whole thing is
divided by the bytes per pixel, plus an extra byte if you are using a
DSTN. The extra byte with DSTN screens is used for the frame
buffering/acceleration in these screens. So for the various Chips and
Technologies chips the maximum specifications are
Max DClk MHz Max Mem Clk MHz
65550 rev A 3.3v 80 38
65550 rev A 5v 110 38
65550 rev B 95 50
65554 94.5 55
65555 110 55
68554 110 55
69000 135 83
69030 170 100
Note that all of the chips except the 65550 rev A are 3.3v only. Which
is the reason for the drop in the dot clock. Now the maximum memory
clock is just the maximum supported by the video processor, not the
maximum supported by the video memory. So the value actually used for
the memory clock might be significantly less than this maximum value.
But assuming your memory clock is programmed to these maximum values
the various maximum dot clocks for the chips are
------CRT/TFT------- --------DSTN--------
8bpp 16bpp 24bpp 8bpp 16bpp 24bpp
65550 rev A 3.3v 80 53.2 35.47 53.2 35.47 26.6
65550 rev A 5v 106.2 53.2 35.47 53.2 35.47 26.6
65550 rev B 95 70 46.67 70 46.67 35.0
65554 94.5 77 51.33 77 51.33 38.5
65555 110 77 51.33 77 51.33 38.5
68554 110 77 51.33 77 51.33 38.5
69000 135 135 135 135 135 116.2
69030 170 170 170 170 170 140
If you exceed the maximum set by the memory clock, you'll get
corruption on the screen during graphics operations, as you will be
starving the HW BitBlt engine of clock cycles. If you are driving the
video memory too fast (too high a MemClk) you'll get pixel corruption
as the data actually written to the video memory is corrupted by
driving the memory too fast. You can probably get away with exceeding
the Max DClk at 8bpp on TFT's or CRT's by up to 10% or so without
problems, it will just generate more heat, since the 8bpp clocks
aren't limited by the available memory bandwidth.
If you find you truly can't achieve the mode you are after with the
default clock limitations, look at the options "DacSpeed" and
"SetMClk". Using these should give you all the capabilities you'll
need in the server to get a particular mode to work. However use
caution with these options, because there is no guarantee that driving
the video processor beyond it capabilities won't cause damage.
7. Troubleshooting
The cursor appears as a white box, after switching modes
There is a known bug in the H/W cursor, that sometimes causes
the cursor to be redrawn as a white box, when the mode is
changed. This can be fixed by moving the cursor to a different
region, switching to the console and back again, or if it is too
annoying the H/W cursor can be disabled by removing the
"HWcursor" option.
The cursor hot-spot isn't at the same point as the cursor
With modes on the 6555x machines that are stretched to fill the
flat panel, the H/W cursor is not correspondingly stretched.
This is a small and long-standing bug in the current server. You
can avoid this by either using the "NoStretch" option or
removing the HWcursor" option.
The lower part of the screen is corrupted
Many DSTN screens use the top of video ram to implement a frame
accelerator. This reduces the amount of video ram available to
the modes. The server doesn't prevent the user from specifying a
mode that will use this memory, it prints a warning on the
console. The effect of this problem will be that the lower part
of the screen will reside in the same memory as the frame
accelerator and will therefore be corrupt. Try reducing the
amount of memory consumed by the mode.
There is a video signal, but the screen doesn't sync.
You are using a mode that your screen cannot handle. If it is a
non-standard mode, maybe you need to tweak the timings a bit. If
it is a standard mode and frequency that your screen should be
able to handle, try to find different timings for a similar mode
and frequency combination. For LCD modes, it is possible that
your LCD panel requires different panel timings at the text
console than with a graphics mode. In this case you will need
the "UseModeline" and perhaps also the "FixPanelSize" options to
reprogram the LCD panel timings to sensible values.
`Wavy' screen.
Horizontal waving or jittering of the whole screen, continuously
(independent from drawing operations). You are probably using a
dot clock that is too high (or too low); it is also possible
that there is interference with a close MCLK. Try a lower dot
clock. For CRT's you can also try to tweak the mode timings;
try increasing the second horizontal value somewhat.
Crash or hang after start-up (probably with a black screen).
Try the "NoAccel" or one of the XAA acceleration options
discussed above. Check that the BIOS settings are OK; in
particular, disable caching of 0xa0000-0xaffff. Disabling hidden
DRAM refresh may also help.
Hang as the first text is appearing on the screen on SVR4
machines.
This problem has been reported under UnixWare 1.x, but not
tracked down. It doesn't occur under UnixWare 2.x and only
occurs on the HiQV series of chips. It might affect some other
SVR4 operating systems as well. The workaround is to turn off
the use of CPU to screen acceleration with the
"XaaNoCPUToScreenColorExapndFill" option.
Crash, hang, or trash on the screen after a graphics operation.
This may be related to a bug in one of the accelerated
functions, or a problem with the BitBLT engine. Try the
"NoAccel" or one of the XAA acceleration options discussed
above. Also check the BIOS settings. It is also possible that
with a high dot clock and depth on a large screen there is very
little bandwidth left for using the BitBLT engine. Try reducing
the clock.
Chipset is not detected.
Try forcing the chipset to a type that is most similar to what
you have.
The screen is blank when starting X
One possible cause of this problem with older linux kernels is
that the "APM_DISPLAY_BLANK" option didn't work correct. Either
upgrade your kernel or rebuild it with the "APM_DISPLAY_BLANK"
option disabled. If the problem remains, or you aren't using
linux, a CRT/LCD or switch to and from the virtual console will
often fix it.
Textmode is not properly restored
This has been reported on some configurations. Many laptops use
the programmable clock of the 6554x chips at the console. It is
not always possible to find out the setting that is used for
this clock if BIOS has written the MClk after the VClk. Hence
the server assumes a 25.175MHz clock at the console. This is
correct for most modes, but can cause some problems. Usually
this is fixed by switching between the LCD and CRT.
Alternatively the user can use the "TextClockFreq" option
described above to select a different clock for the text
console. Another possible cause of this problem is if linux
kernels are compiled with the "APM_DISPLAY_BLANK" option. As
mentioned before, try disabling this option.
I can't display 640x480 on my 800x600 LCD
The problem here is that the flat panel needs timings that are
related to the panel size, and not the mode size. There is no
facility in the current Xservers to specify these values, and so
the server attempts to read the panel size from the chip. If the
user has used the "UseModeline" or "FixPanelSize" options the
panel timings are derived from the mode, which can be different
than the panel size. Try deleting theses options from xorg.conf
or using an LCD/CRT switch.
I can't get a 320x240 mode to occupy the whole 640x480 LCD
There is a bug in the 6554x's H/W cursor for modes that are
doubled vertically. The lower half of the screen is not
accessible. The servers solution to this problem is not to do
doubling vertically. Which results in the 320x240 mode only
expanded to 640x360. If this is a problem, a work around is to
remove the "HWcursor" option. The server will then allow the
mode to occupy the whole 640x480 LCD.
After a suspend/resume my screen is messed up
During a suspend/resume, the BIOS controls what is read and
written back to the registers. If the screen is using a mode
that BIOS doesn't know about, then there is no guarantee that it
will be resumed correctly. For this reason a mode that is as
close to VESA like as possible should be selected. It is also
possible that the VGA palette can be affected by a
suspend/resume. Using an 8bpp, the colour will then be
displayed incorrectly. This shouldn't affect higher depths, and
is fixable with a switch to the virtual console and back.
The right hand edge of the mode isn't visible on the LCD
This is usually due to a problem with the "LcdCenter" option. If
this option is removed form xorg.conf, then the problem might go
away. Alternatively the manufacturer could have incorrectly
programmed the panel size in the EGA console mode. The
"FixPanelSize" can be used to force the modeline values into the
panel size registers. Two machines that are known to have this
problem are the "HP OmniBook 5000" and the "NEC Versa 4080".
My TFT screen has a reddish tint in 24bpp mode
For 6554x chipsets the server assumes that the TFT bus width is
24bits. If this is not true then the screen will appear to have
a reddish tint. This can be fixed by using the "18BitBus"
option. Note that the reverse is also true. If the "18BitBus" is
used and the TFT bus width is 24bpp, then the screen will appear
reddish. Note that this option only has an effect on TFT
screens.
SuperProbe won't work with my chipset
At least one non-PCI bus system with a HiQV chipset has been
found to require the "-no_bios" option for SuperProbe to
correctly detect the chipset with the factory default BIOS
settings. The server itself can correctly detect the chip in the
same situation.
My 690xx machine lockups when using the
The 690xx MMIO mode has been implemented entirely from the
manual as I don't have the hardware to test it on. At this point
no testing has been done and it is entirely possible that the
"MMIO option will lockup your machine. You have been warned!
However if you do try this option and are willing to debug it,
I'd like to hear from you.
My TrueColor windows are corrupted when using the
Chips and Technologies specify that the memory clock used with
the multimedia engine running should be lower than that used
without. As use of the HiQV chipsets multimedia engine was
supposed to be for things like zoomed video overlays, its use
was supposed to be occasional and so most machines have their
memory clock set to a value that is too high for use with the
"Overlay" option. So with the "Overlay" option, using the
"SetMClk" option to reduce the speed of the memory clock is
recommended.
The mpeg video playing with the XVideo extension has corrupted
colours
The XVideo extension has only recently been added to the chips
driver. Some YUV to RGB colour have been noted at 15 and 16 bit
colour depths. However, 8 and 24 bit colour depths seem to work
fine.
My ct69030 machine locks up when starting X
The ct69030 chipset introduced a new dual channel architecture.
In its current form, X can not take advantage of this second
display channel. In fact if the video BIOS on the machine sets
the ct69030 to a dual channel mode by default, X will lockup
hard at this point. The solution is to use the BIOS setup to
change to a single display channel mode, ensuring that both the
IOSS and MSS registers are set to a single channel mode. Work is
underway to fix this.
I can't start X-windows with 16, 24 or 32bpp
Firstly, is your machine capable of 16/24/32bpp with the mode
specified. Many LCD displays are incapable of using a 24bpp
mode. Also you need at least a 65540 to use 16/24bpp and at
least a 65550 for 32bpp. The amount of memory used by the mode
will be doubled/tripled/quadrupled. The correct options to start
the server with these modes are
startx -- -depth 16 5-6-5 RGB ('64K color', XGA)
startx -- -depth 15 5-5-5 RGB ('Hicolor')
startx -- -depth 24 8-8-8 RGB truecolor
or with the HiQV series of chips you might try
startx -- -depth 24 -fbbpp 32 8-8-8 RGB truecolor
however as X11R7.5 allows 32bpp pixmaps to be used with frame-
buffers operating in 24bpp, this mode of operating will cost per-
formance for no gain in functionality.
Note that the "-bpp" option has been removed and replaced with a
"-depth" and "-fbbpp" option because of the confusion between the
depth and number of bits per pixel used to represent to framebuffer
and the pixmaps in the screens memory.
A general problem with the server that can manifested in many way such
as drawing errors, wavy screens, etc is related to the programmable
clock. Many potential programmable clock register setting are
unstable. However luckily there are many different clock register
setting that can give the same or very similar clocks. The clock code
can be fooled into giving a different and perhaps more stable clock by
simply changing the clock value slightly. For example 65.00MHz might
be unstable while 65.10MHz is not. So for unexplained problems not
addressed above, please try to alter the clock you are using slightly,
say in steps of 0.05MHz and see if the problem goes away.
Alternatively, using the "CRTClkIndx" or "FPClkIndx" option with HiQV
chips might also help.
For other screen drawing related problems, try the "NoAccel" or one of
the XAA acceleration options discussed above. A useful trick for all
laptop computers is to switch between LCD/CRT (usually with something
like Fn-F5), if the screen is having problems.
If you are having driver-related problems that are not addressed by
this document, or if you have found bugs in accelerated functions, you
can try contacting the Xorg team (the current driver maintainer can be
reached at <mailto:eich@freedesktop.org>).
8. Disclaimer
The Xorg X server, allows the user to do damage to their hardware with
software with old monitors which may not tolerate bad display
settings. Although the authors of this software have tried to prevent
this, they disclaim all responsibility for any damage caused by the
software. Use caution, if you think the X server is frying your
screen, TURN THE COMPUTER OFF!!
9. Acknowledgement
The authors of this software wish to acknowledge the support supplied
by Chips and Technologies during the development of this software.
10. Authors
Major Contributors (In no particular order)
o Nozomi Ytow
o Egbert Eich
o David Bateman
o Xavier Ducoin
Contributors (In no particular order)
o Ken Raeburn
o Shigehiro Nomura
o Marc de Courville
o Adam Sulmicki
o Jens Maurer
We also thank the many people on the net who have contributed by
reporting bugs and extensively testing this server.
