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+<!DOCTYPE linuxdoc PUBLIC "-//XFree86//DTD linuxdoc//EN">
+
+<article>
+
+<!-- Title information -->
+<title> Information for Chips and Technologies Users
+<author> David Bateman (<it>dbateman@ee.uts.edu.au</it>),
+ Egbert Eich (<it>Egbert.Eich@Physik.TH-Darmstadt.DE</it>)
+<date> 28th July 1997
+
+<!-- Table of contents -->
+<toc>
+
+<sect> Introduction <p>
+
+The Chips and Technologies range of chips are primarily manufactured
+for use in laptop computers, where their power conservation circuitry
+is of importance. They can however be found in a few "<tt>Green</tt>"
+video cards for desktop machines. This release of XFree includes
+support for
+
+<itemize>
+<item>Linear Addressing
+<item>16/ 24 bits per pixel
+<item>Fully programmable clocks are supported
+<item>H/W cursor support
+<item>BitBLT acceleration of many operations using XAA
+</itemize>
+
+Most of the Chips and Technologies chipsets are supported by this driver
+to some degree.
+
+<sect> Supported Chips <p>
+<descrip>
+<tag>ct65520</tag>
+ (Max Ram: 1Mb, Max Dclk: 68MHz@5V)
+<tag>ct65525</tag>
+ 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.
+<tag>ct65530</tag>
+ 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)
+<tag>ct65535</tag>
+ This is the first chip of the ct655xx series to support fully
+ programmable clocks. Otherwise it has the the same properties
+ as the 65530.
+<tag>ct65540</tag>
+ 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)
+<tag>ct65545</tag>
+ 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)
+<tag>ct65546</tag>
+ 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?)
+<tag>ct65548</tag>
+ 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)
+<tag>ct65550</tag>
+ This chip started a completely new architecture to previous ct655xx
+ chips. It includes many new features, including improved BitBLT
+ support (24bpp color expansion, wider maximum pitch, etc), Multimedia
+ unit (video capture, zoom video port, etc) and 24bpp uncompressed true
+ color (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)
+<tag>ct65554</tag>
+ 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)
+<tag>ct65555</tag>
+ 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)
+<tag>ct68554</tag>
+ 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)
+<tag>ct64200</tag>
+ 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)
+<tag>ct64300</tag>
+ This is a more advanced version of the WinGine chip, with specification
+ very similar to the 6554x series of chips. However there are many
+ difference at a register level. A similar level of acceleration to
+ the 65545 is included for this driver.
+ (Max Ram: 2Mb, Max Dclk: 80MHz)
+</descrip>
+
+<sect> XF86Config Options <p>
+
+The following options are of particular interest to the Chips
+and Technologies driver. Each of them must be specified in the
+`svga' driver section of the XF86Config file, within the Screen
+subsections of the depths to which they are applicable (you can enable
+options for all depths by specifying them in the Device section).
+
+<descrip>
+<tag>
+Option &dquot;noaccel&dquot;
+</tag>
+ 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).
+<tag>
+Option &dquot;no_bitblt&dquot; (Chips 65545 and later)
+</tag>
+ This option will disable the use of the BitBLT engine which the
+ 65545 and above have. If you can use the "<tt>noaccel</tt>" option
+ to correct a problem, then this option might be better to use.
+ It still allows the use of generic speedups.
+<tag>
+Option &dquot;xaa_no_color_exp&dquot; (Chips 65545 and later)
+</tag>
+ This option will have the effect of disabling the use
+ of monochrome colour expansion. In particular this effects
+ text and bitmaps. It is useful for problems related to image writes,
+ and possible acceleration problems. In general this will result in
+ a reduced performance. Note that this option replaces the
+ "<tt>no_imageblt</tt>" option used in XFree 3.2.
+<tag>
+Option &dquot;xaa_benchmark&dquot; (Chips 65545 and later)
+</tag>
+ Turns on the XAA acceleration benchmarks. Information regarding
+ what graphics primitives are accelerated and their relatives
+ speeds will be printed when the X server starts.
+<tag>
+videoram 1024 (or another value)
+</tag>
+ This option will override the detected amount of video memory,
+ and pretend the given amount of memory is present on the card.
+ Note that many ct655xx chips only allow up to 1Mb of videoram,
+ and the amount should be correctly detected.
+<tag>
+Option &dquot;nolinear&dquot; (Chips 65530 and later)
+</tag>
+ By default linear addressing is used on all ct655xx chips.
+ However this might be broken in some implementations. It
+ is possible to turn the linear addressing off with this
+ option. Note that H/W acceleration and 16/24bpp are only
+ supported with linear addressing.
+<tag>
+MemBase 0x03b00000 (or a different address)
+</tag>
+ 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.
+<tag>
+Option &dquot;sw_cursor&dquot; (Chips 65545 and later)
+</tag>
+ This disables use of the hardware cursor provided by the chip.
+ Try this if the cursor seems to have problems.
+<tag>
+Option &dquot;STN&dquot;
+</tag>
+ 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.
+<tag>
+Option &dquot;use_modeline&dquot;
+</tag>
+ The flat panel timings are related to the panel size and not the
+ size of the mode specified in XF86Config. 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.
+<tag>
+Option &dquot;fix_panel_size&dquot;
+</tag>
+ 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
+ &dquot;use_modeline&dquot; to program all the panel timings using
+ the modeline values.
+<tag>
+Option &dquot;no_stretch&dquot;
+</tag>
+ 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 "<tt>letterbox</tt>" effect with no stretching
+ can be achieved using this option.
+<tag>
+Option &dquot;lcd_center&dquot;
+</tag>
+ 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 16/24bpp, the effect of which
+ is that the right-hand edge of the mode will be pushed off the screen.
+<tag>
+Option &dquot;hw_clocks&dquot; (Chips 65535 and later)
+</tag>
+ On chips 65535 and later, 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
+ "<tt>TextClockFreq</tt>" 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.
+<tag>
+Option &dquot;use_vclk1&dquot; (Chips 65550 and later)
+</tag>
+ 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. This option
+ forces the use of VClk1 as the programmable clock.
+<tag>
+TextClockFreq 25.175
+</tag>
+ It is impossible for the server to read the value of the currently
+ used frequency for the text console from the chip with the ct6554x
+ series of chips. 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.
+<tag>
+Option &dquot;mmio&dquot;
+</tag>
+ This enables the use of memory-mapped I/O to talk to the BitBLT
+ engine. By default memory-mapped I/O is not enabled on the
+ 6554x series of chips, and is only usable on 6554x's with PCI
+ buses. This option has no effect when not using the BitBLT engine
+ (e.g. when using "<tt>no_bitblt</tt>"), or for the 65550 which can
+ only use MMIO for access to the BitBLT engine. On 65545 PCI
+ machines MMIO is enabled by default because the blitter can not
+ be used otherwise.
+<tag>
+Option &dquot;suspend_hack&dquot;
+</tag>
+ 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 &dquot;lcd_center&dquot;
+ and &dquot;no_stretch&dquot;.
+<tag>
+Option &dquot;use_18bit_bus&dquot; (Chips 65540/45/46/48)
+</tag>
+ 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.
+<tag>
+Chipset &dquot;ct65546&dquot; (or some other chip)
+</tag>
+ 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.
+<tag>
+Option &dquot;sync_on_green&dquot; (Chips 65550/54/55 and 68554)
+</tag>
+ Composite sync on green. Possibly useful if you wish to use an
+ old workstation monitor. The 65550/54 internal RAMDAC's support
+ this mode of operation, but whether a particular machine does
+ depends on the manufacturer.
+<tag>
+Option &dquot;fast_dram&dquot; (Chips 65550/54/55 and 68554)
+</tag>
+ This option sets the internal memory clock (MCLK) registers to 38MHz.
+ The default value programmed by the BIOS is usually OK, but some
+ machines can accept a faster MClk to achieve a better performance.
+ One machine known to work well with this option is the Toshiba 720CDT.
+ Note that newer machines often have an MClk greater than 38MHz, and
+ so this option might actually slower the machine down. This option
+ is generally not recommended and is superseded by the
+ "<tt>Set_MemClk</tt>" option.
+<tag>
+DacSpeed 80.000
+</tag>
+ 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.
+<tag>
+Set_MemClk 38.000 (Chips 65550/54/55 and 68554)
+</tag>
+ This option sets the internal memory clock (MCLK) registers 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.
+</descrip>
+
+<sect> Modelines <p>
+
+When constructing a modeline for use with the Chips and Technologies
+driver you'll needed to considered several points
+
+<descrip>
+<tag> * Virtual Screen Size </tag>
+ 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.
+<tag> * 16/24 Bits Per Pixel </tag>
+ Chips later than the ct65540 are capable of supporting
+ Hi-Color and True-Color modes. These are implemented in the current
+ 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 6555x 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 bpp modes will need 2 or 3 times respectively more video
+ ram.
+<tag> * Frame Acceleration</tag>
+ 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).
+<tag> * H/W Acceleration </tag>
+ The H/W cursor will need 1kB for the 6554x and 4kb for the
+ 65550. On the 64300 chips the H/W cursors 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
+ "<tt>pixmap cache</tt>". Leaving too little memory available for
+ the cache will only have a detrimental effect on the graphics
+ performance.
+<tag> * VESA like modes </tag>
+ 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.
+<tag> * Dot Clock </tag>
+ 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.
+</descrip>
+
+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 XF86Config files, such as "<tt>xf86config</tt>"
+or "<tt>XF86Setup</tt>".
+
+However there are many machines, particular 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 "<tt>use_modeline</tt>" and/or possibly the
+"<tt>fix_panel_size</tt>" option might be needed. Some machines that
+are known to need these options include.
+
+<quote><verb>
+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: "use_modeline"
+Tested on a Prostar 8200, (640x480, 65548, 1Mbyte)
+</verb></quote>
+
+<quote><verb>
+Modeline "800x600@8bpp" 28.322 800 808 848 936 600 600 604 628
+Options: "fix_panel_size", "use_modeline"
+Tested on a HP OmniBook 5000CTS (800x600 TFT, 65548, 1Mbyte)
+</verb></quote>
+
+<quote><verb>
+Modeline "800x600@8bpp" 30.150 800 896 960 1056 600 600 604 628
+Options: "fix_panel_size", "use_modeline"
+Test on a Zeos Meridan 850c (800x600 DSTN, 65545, 1Mbyte)
+</verb></quote>
+
+The NEC Versa 4080 just needs the "fix_panel_size" option.
+
+<sect> Troubleshooting <p>
+
+<descrip>
+<tag> The cursor appears as a white box, after switching modes</tag>
+ 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 with the "<tt>sw_cursor</tt>" option.
+<tag> The cursor hot-spot isn't at the same point as the cursor</tag>
+ 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 "<tt>no_stretch</tt>" or
+ <tt>sw_cursor</tt>" options.
+<tag> The lower part of the screen is corrupted</tag>
+ 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.
+<tag> There is a video signal, but the screen doesn't sync.</tag>
+ 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
+ "<tt>use_modeline</tt>" and perhaps also the "<tt>fix_panel_size</tt>"
+ options to reprogram the LCD panel timings to sensible values.
+<tag> `Wavy' screen.</tag>
+ 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.
+<tag> Crash or hang after start-up (probably with a black screen).</tag>
+ Try the "<tt>noaccel</tt>" or "<tt>no_bitblt</tt>" options. Check
+ that the BIOS settings are OK; in particular, disable caching of
+ 0xa0000-0xaffff. Disabling hidden DRAM refresh may also help.
+<tag> Hang as the first text is appearing on the screen on SVR4 machines.</tag>
+ 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 "<tt>xaa_no_color_exp</tt>" option.
+<tag> Crash, hang, or trash on the screen after a graphics operation.</tag>
+ This may be related to a bug in one of the accelerated
+ functions, or a problem with the BitBLT engine. Try the
+ "<tt>noaccel</tt>" or "<tt>no_bitblt</tt>" options. 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.
+<tag> Chipset is not detected.</tag>
+ Try forcing the chipset to a type that is most similar to what
+ you have.
+<tag>The screen is blank when starting X</tag>
+ One possible cause of this problem is if the kernel has been
+ compiled with the "APM_DISPLAY_BLANK" option. It appears that
+ this option doesn't work as specified and can cause the Xserver
+ to blank when starting X. In all cases the kernel should be compiled
+ without this option. If the problem remains a CRT/LCD or switch to
+ and from the virtual console will often fix it.
+<tag> Textmode is not properly restored</tag>
+ 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 "<tt>TextClockFreq</tt>"
+ option described above to select a different clock for the
+ text console. Another possible cause of this problem is if the kernel
+ is compiled with the "APM_DISPLAY_BLANK" option. As mentioned
+ before, this option should be disabled.
+<tag> I can't display 640x480 on my 800x600 LCD</tag>
+ 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 "<tt>use_modeline</tt>" or
+ "<tt>fix_panel_size</tt>" options the panel timings are derived
+ from the mode, which can be different than the panel size. Try
+ deleting theses options from XF86Config or using an LCD/CRT switch.
+<tag> I can't get a 320x240 mode to occupy the whole 640x480 LCD</tag>
+ 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 use the "<tt>sw_cursor</tt>"
+ option. The server will then allow the mode to occupy the whole
+ 640x480 LCD.
+<tag> After a suspend/resume my screen is messed up</tag>
+ 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.
+<tag> The right hand edge of the mode isn't visible on the LCD</tag>
+ This is usually due to a problem with the "<tt>lcd-center</tt>"
+ option. If this option is removed form XF86Config, then the problem
+ might go away. Alternatively the manufacturer could have incorrectly
+ programmed the panel size in the EGA console mode. The
+ "<tt>fix_panel_size</tt>" can be used to force the modeline values into
+ the panel size registers. Two machines that are known to have this
+ problem are the "<tt>HP OmniBook 5000</tt>" and the "<tt>NEC Versa
+ 4080</tt>".
+<tag> My TFT screen has a reddish tint in 24bpp mode</tag>
+ 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 "<tt>use_18bit_bus</tt>" option. Note that
+ the reverse is also true. If the "<tt>use_18bit_bus</tt>" 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.
+<tag> I can't start X-windows with 16 or 24bpp</tag>
+ Firstly, is your machine capable of 16/24bpp 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 the
+ amount of memory used by the mode will be doubled/tripled. The
+ correct options to start the server with these modes are
+<verb>
+ startx -- -bpp 16 5-6-5 RGB ('64K color', XGA)
+ startx -- -bpp 16 -weight 555 5-5-5 RGB ('Hicolor')
+ startx -- -bpp 24 8-8-8 RGB truecolor
+</verb>
+ Note that there is currently no "<tt>-bpp 32</tt>" mode in the Xserver,
+ although the 65550 is capable of this.
+</descrip>
+
+
+ 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.
+
+ For other screen drawing related problems, try the "<tt>noaccel</tt>" or
+ "<tt>no_bitblt</tt>" options. 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 XFree86 team (the current driver maintainer can be
+ reached at <it>dbateman@eng.uts.edu.au</it> or
+ <it>Egbert.Eich@Physik.TH-Darmstadt.DE)</it>,
+ or post in the Usenet newsgroup "<it>comp.windows.x.i386unix</it>".
+
+<sect> Disclaimer <p>
+
+Xfree, allows the user to do damage to their hardware with software.
+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 Xserver is frying your screen, TURN THE COMPUTER
+OFF!!
+
+<sect> Acknowledgement <p>
+
+The authors of this software wish to acknowledge the support
+supplied by Chips and Technologies during the development of this
+software.
+
+<sect> Authors <p>
+
+<tt>Major Contributors</tt> (In no particular order)
+<itemize>
+<item>Nozomi Ytow
+<item>Egbert Eich
+<item>David Bateman
+<item>Xavier Ducoin
+</itemize>
+
+<tt>Contributors</tt> (In no particular order)
+<itemize>
+<item>Ken Raeburn
+<item>Shigehiro Nomura
+<item>Marc de Courville
+<item>Adam Sulmicki
+<item>Jens Maurer
+</itemize>
+
+We also thank the many people on the net who have contributed by reporting
+bugs and extensively testing this server before its inclusion in XFree 3.2
+
+<verb>
+$XFree86: xc/programs/Xserver/hw/xfree86/doc/sgml/chips.sgml,v 3.12.2.7 1998/01/31 14:23:27 hohndel Exp $
+</verb>
+
+</article>