Differences between version 3 and revision by previous author of HowToXFree86VideoTimingsHOWTO.
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| Newer page: | version 3 | Last edited on Friday, April 2, 2004 7:22:23 am | by JacobAnawalt | Revert |
| Older page: | version 2 | Last edited on Friday, June 7, 2002 1:07:51 am | by perry | Revert |
@@ -13,10 +13,14 @@
$Date: 2002/02/04 18:01:47 $
-__Revision History__Revision 6.22002-02-03Revised by: esrMinor corrections about mode line autogeneration.Revision 6.12001-10-29Revised by: esrNote that VESA modes top out at 1920x1440.Revision 6.02001-08-09Revised by: esrClearer explanation of DDC and EDID. This HOWTO is now
-basically obsolete.Revision 5.02000-08-22Revised by: esrFirst !DocBook version.
+__Revision History__
+
Revision 6.22002-02-03Revised by: esrMinor corrections about mode line autogeneration.
+
Revision 6.12001-10-29Revised by: esrNote that VESA modes top out at 1920x1440.
+
Revision 6.02001-08-09Revised by: esrClearer explanation of DDC and EDID. This HOWTO is now
+basically obsolete.
+
Revision 5.02000-08-22Revised by: esrFirst !DocBook version.
@@ -40,9 +44,40 @@
-----; __Table of Contents__; 1.
Disclaimer; 2.
Why This HOWTO Is Obsolete; 3.
Introduction; 4.
Tools for Automatic Computation; 5.
How Video Displays Work; 6.
Basic Things to Know about your Display and Adapter: ; 6.1.
The monitor sync frequencies; 6.2.
The monitor's video bandwidth; 6.3.
The card's dot clock; 6.4.
What these basic statistics control; 7.
Interpreting the Basic Specifications: ; 7.1.
About Bandwidth; 7.2.
Sync Frequencies and the Refresh Rate:; 8.
Tradeoffs in Configuring your System; 9.
Memory Requirements; 10.
Computing Frame Sizes; 11.
Black Magic and Sync Pulses: ; 11.1.
Horizontal Sync:; 11.2.
Vertical Sync:; 12.
Putting it All Together; 13.
Overdriving Your Monitor; 14.
Using Interlaced Modes; 15.
Questions and Answers; 16.
Fixing Problems with the Image.: ; 16.1.
The image is displaced to the left or right; 16.2.
The image is displaced up or down; 16.3.
The image is too large both horizontally and vertically; 16.4.
The image is too wide (too narrow) horizontally; 16.5.
The image is too deep (too shallow) vertically; 17.
Plotting Monitor Capabilities; 18.
Credits----
+----; __Table of Contents__;
+#
Disclaimer;
+#
Why This HOWTO Is Obsolete;
+#
Introduction;
+#
Tools for Automatic Computation;
+#
How Video Displays Work;
+#
Basic Things to Know about your Display and Adapter: ;
+##
The monitor sync frequencies;
+##
The monitor's video bandwidth;
+##
The card's dot clock;
+##
What these basic statistics control;
+#
Interpreting the Basic Specifications: ;
+##
About Bandwidth;
+##
Sync Frequencies and the Refresh Rate:;
+#
Tradeoffs in Configuring your System;
+#
Memory Requirements;
+#
Computing Frame Sizes;
+#
Black Magic and Sync Pulses: ;
+##
Horizontal Sync:;
+##
Vertical Sync:;
+#
Putting it All Together;
+#
Overdriving Your Monitor;
+#
Using Interlaced Modes;
+#
Questions and Answers;
+#
Fixing Problems with the Image.: ;
+##
The image is displaced to the left or right;
+##
The image is displaced up or down;
+##
The image is too large both horizontally and vertically;
+##
The image is too wide (too narrow) horizontally;
+##
The image is too deep (too shallow) vertically;
+#
Plotting Monitor Capabilities;
+#
Credits----
!!!1. Disclaimer
You use the material herein ''solely at your own
risk''. It is possible to harm both your monitor and yourself
@@ -80,18 +115,18 @@
create a Display section describing it. Here is a sample Screen
description from the X configuration file of my laptop:
-Section "Screen"
-Identifier "Screen0"
-Device "ATI Rage Mobility"
-Monitor "Monitor0"
-!DefaultDepth 16
-Subsection "Display"
-Depth 16
-Modes "1024x768"
-!EndSubsection
-!EndSection
+
Section "Screen"
+
Identifier "Screen0"
+
Device "ATI Rage Mobility"
+
Monitor "Monitor0"
+
!DefaultDepth 16
+
Subsection "Display"
+
Depth 16
+
Modes "1024x768"
+
!EndSubsection
+ !EndSection
All you will usually need to do is change the numbers in the
Mode entry. X will do the rest. If you specify an impossible
resolution, it will fall back to the closest approximation that the EDID
@@ -248,9 +283,9 @@
We say "what you could consider to be a series of dots" because
these raster dots don't actually correspond to physical phosphor dots.
The physical phosphor dots are much smaller than raster dots -- they
have to be, otherwise the display would suffer from severe
-moiré
-pattern effects. The raster dots are really samples of
+moir�
-pattern effects. The raster dots are really samples of
the analog driver signal, and display as a grid of dots only because
the peaks and valleys in the signal are quite regularly and finely
spaced.
@@ -405,14 +440,14 @@
bandwidth estimates (and thus into rough upper bounds for the dot
clock you can use):
-
640x480
25
-800x600
36
-1024x768 65
-1024x768 interlaced 45
-1280x1024 110
-1600x1200 185
+
640x480
25
+ 800x600
36
+ 1024x768 65
+ 1024x768 interlaced 45
+ 1280x1024 110
+ 1600x1200 185
BTW, there's nothing magic about this table; these numbers are just
the lowest dot clocks per resolution in the standard XFree86 Modes
database (except for the last, which I extrapolated). The bandwidth
@@ -428,21 +463,21 @@
following are examples:
Brand Video Bandwidth
----------- ---------------
-NEC 4D 75Mhz
-Nano 907a 50Mhz
-Nano 9080i 60Mhz
-Mitsubishi HL6615 110Mhz
-Mitsubishi Diamond Scan
100Mhz
-IDEK MF-5117 65Mhz
-IOCOMM Thinksync-17 CM-7126 136Mhz
-HP D1188A 100Mhz
-Philips SC-17AS
110Mhz
-Swan SW617 85Mhz
-Viewsonic 21PS 185Mhz
-!PanaSync/Pro P21 220Mhz
+
---------- ---------------
+ NEC 4D 75Mhz
+ Nano 907a 50Mhz
+ Nano 9080i 60Mhz
+ Mitsubishi HL6615 110Mhz
+ Mitsubishi Diamond Scan 100Mhz
+ IDEK MF-5117 65Mhz
+ IOCOMM Thinksync-17 CM-7126 136Mhz
+ HP D1188A 100Mhz
+ Philips SC-17AS
110Mhz
+ Swan SW617 85Mhz
+ Viewsonic 21PS 185Mhz
+ !PanaSync/Pro P21 220Mhz
Even low-end monitors usually aren't terribly
bandwidth-constrained for their rated resolutions. The NEC Multisync
II makes a good example --- it can't even display 800x600 per its
@@ -491,45 +526,45 @@
If you're using XFree86:
-Xconfig: /usr/X11R6/lib/X11/Xconfig
-(**) stands for supplied, (--) stands for probed/default values
-(**) Mouse: type: !MouseMan, device: /dev/ttyS1, baudrate: 9600
-Warning: The directory "/usr/andrew/X11fonts" does not exist.
-Entry deleted from font path.
-(**) !FontPath set to "/usr/lib/X11/fonts/misc/,/usr/lib/X11/fonts/75dpi/"
-(--) S3: card type: 386/486 localbus
-(--) S3: chipset: 924
----
-Chipset -- this is the exact chip type; an early mask of the 86C911
-(--) S3: chipset driver: s3_generic
-(--) S3: videoram: 1024k
------
-Size of on-board frame-buffer RAM
-(**) S3: clocks: 25.00 28.00 40.00 3.00 50.00 77.00 36.00 45.00
-(**) S3: clocks: .00 .00 79.00 31.00 94.00 65.00 75.00 71.00
-------------------------------------------------------
-Possible driving frequencies in MHz
-(--) S3: Maximum allowed dot-clock: 110MHz
-------
-Bandwidth
-(**) S3: Mode "1024x768": mode clock = 79.000, clock used = 79.000
-(--) S3: Virtual resolution set to 1024x768
-(--) S3: Using a banksize of 64k, line width of 1024
-(--) S3: Pixmap cache:
-(--) S3: Using 2 128-pixel 4 64-pixel and 8 32-pixel slots
-(--) S3: Using 8 pages of 768x255 for font caching
+
Xconfig: /usr/X11R6/lib/X11/Xconfig
+ (**) stands for supplied, (--) stands for probed/default values
+ (**) Mouse: type: !MouseMan, device: /dev/ttyS1, baudrate: 9600
+ Warning: The directory "/usr/andrew/X11fonts" does not exist.
+ Entry deleted from font path.
+ (**) !FontPath set to "/usr/lib/X11/fonts/misc/,/usr/lib/X11/fonts/75dpi/"
+ (--) S3: card type: 386/486 localbus
+ (--) S3: chipset: 924
+ ---
+ Chipset -- this is the exact chip type; an early mask of the 86C911
+ (--) S3: chipset driver: s3_generic
+ (--) S3: videoram: 1024k
+ -----
+ Size of on-board frame-buffer RAM
+ (**) S3: clocks: 25.00 28.00 40.00 3.00 50.00 77.00 36.00 45.00
+ (**) S3: clocks: .00 .00 79.00 31.00 94.00 65.00 75.00 71.00
+ ------------------------------------------------------
+ Possible driving frequencies in MHz
+ (--) S3: Maximum allowed dot-clock: 110MHz
+ ------
+ Bandwidth
+ (**) S3: Mode "1024x768": mode clock = 79.000, clock used = 79.000
+ (--) S3: Virtual resolution set to 1024x768
+ (--) S3: Using a banksize of 64k, line width of 1024
+ (--) S3: Pixmap cache:
+ (--) S3: Using 2 128-pixel 4 64-pixel and 8 32-pixel slots
+ (--) S3: Using 8 pages of 768x255 for font caching
If you're using SGCS or X/Inside X:
-WGA: 86C911 (mem: 1024k clocks: 25 28 40 3 50 77 36 45 0 0 79 31 94 65 75 71)
---- ------ ----- --------------------------------------------
-| | | Possible driving frequencies in MHz
-| | +-- Size of on-board frame-buffer RAM
-| +-- Chip type
-+-- Server type
+
WGA: 86C911 (mem: 1024k clocks: 25 28 40 3 50 77 36 45 0 0 79 31 94 65 75 71)
+ --- ------ ----- --------------------------------------------
+ | | | Possible driving frequencies in MHz
+ | | +-- Size of on-board frame-buffer RAM
+ | +-- Chip type
+ +-- Server type
Note: do this with your machine unloaded (if at all possible).
Because X is an application, its timing loops can collide with disk
activity, rendering the numbers above inaccurate. Do it several times
@@ -547,9 +582,9 @@
example above:
wga
-Clocks 25 28 40 3 50 77 36 45 0 0 79 31 94 65 75 71
+
Clocks 25 28 40 3 50 77 36 45 0 0 79 31 94 65 75 71
On systems with a highly variable load, this may help you avoid
mysterious X startup failures. It's possible for X to come up, get
its timings wrong due to system load, and then not be able to find a
