Bug#308610: xserver-xfree86: Monitor rolls with resolution > VGA (640x480)
On Friday 12 August 2005 00:04, Charles P. Pouliot wrote:
| Package: xserver-xfree86
| Version: 4.3.0.dfsg.1-14
| Followup-For: Bug #308610
|
|
| Package: xserver-xfree86
| Version: 4.3.0.1 (Debian 4.3.0.dfsg.1-14 20050601051219
| Subject: XFree86 version 4 hardware bug
|
|<>
|I don't think I have the resources to compile the whole X server.
xorg 6.8.2 took 7 hours on my 200MHz Pentium1 last week
(i havent had time to see whether it gave a working result though),
and is faster if you specify to not build fonts
(you already have fonts).
| It is the "correct" modelines which are automatically supplied by the X
| server which caused my problem, as described below in 'original bug
| report.'
|<> My monitor rolls like a TV that doesn't have a V-HOLD properly adjusted,
| which is of course due to a problem with the Vertical refresh rate.
or vertical refresh duration, or incorrect syncpulse timings
|<>the video card is signaling too low a Vertical refresh rate.
| My monitor reports the Display frequency being sent to it, which
| assisted the below diagnosis.
As your monitor fails to sync, what it reports is not very reliable.
| I cannot start X using the "ati" driver for my Mach64 Chrontel 8398
| RAMDAC. The monitor goes VESA power off, and if I try to switch video
| modes, my monitor display just rolls out of control.
When it rolls, does it show any image ?
i mean, could whatever it shows be due to a working X server ?
after all, if the monitor does get a signal,
it is probable that X has started,
and is producing output (which your monitor can not display).
Does the command with which X is started produce any errormessages ?
Is there anything in your $HOME/.xsession-errors ?
Your original config file has :
| Section "Monitor"
| Identifier "ViewSonic 17GS"
| HorizSync 30-69
| VertRefresh 50-160
| Option "DPMS"
| EndSection
What happens if you change that to horiz: 30-50 and vertical 50-90 ?
does that get you a usable 1024x768@62Hz ?
(It could be that your monitor only does 68.9 kHz, and X drives it at 69.0)
Could you try with a different monitor
(to rule out monitor hardware malfunction) ?
| The "incorrect" modelines in my config file are precisely those
| which DO WORK!
| Modes "1024x768" "800x600" "640x480"
So 1024x768 causes no display, and 800x600 causes rolling. correct ?
most Mach64s can do 170MHz or so,
so it would be limited by horizontal refresh rate specified in config file
(69kHz).
69 kHz / 800 = 86.2 Hz -> no display <- 69 kHz x 1312 = 90.5 MHz
69 kHz / 625 = 110.4 Hz -> rolling display <- 69 kHz x 1056 = 72.8 MHz
This is clearly a bug. A monitor should have no problem with this.
Question is : is this a bug in X, or in your configuration parameters,
or in your hardware ?
|## VESA Standard 1024x786@75Hz:
| "1024x768" 78.75 1024 1040 1136 1312 768 769 772 800 -hsync -vsync
from http://www.xfree86.org/3.3.6/Config7.html :
# name clock horizontal timing vertical timing flags
"1024x768" 75 1024 1048 1184 1328 768 771 777 806 -hsync -vsync
Apparently i was wrong about vertical retrace taking 20% of time ;
sorry about that.
I also have a mach64 (3d rage), and when i used to have a very old monitor,
reducing vertical retrace to 10% was pushing it's limits.
|## My hack:
| "1024x768" 79.50 1024 1044 1076 1318 768 772 778 802 -hsync -vsync
| "800x600" 69.65 800 844 908 1068 600 604 610 636 -hsync -vsync
| "640x480" 45.80 640 684 780 844 480 492 498 526 -hsync -vsync
| VESA Standard 800x600@75Hz:
| "800x600" 49.5 800 816 896 1056 600 601 604 625
| VESA Standard 640x480@75Hz:
| "640x480" 31.50 640 656 720 840 480 481 484 500 +hsync +vsync
| If I use the "vga" driver or the "ati" driver with a color depth of 4,
| causing it to use the VGA CRT controller, I am able to get a 640x480
| display, and a very flickery 800x600 display.
If you use xvidtune from these modes,
what are the limits within which your monitor displays correctly ?
(Usefull to know in case your monitor specs in config file are too optimistic)
| My hardware: ViewSonic 17GS monitor, ATI Mach64 video card detected as
| ATI 88800GX-D graphics controller, Pentium-120 with PCI and ISA slots.
| My software: Linux kernel 2.2.19 / 2.4.31, xfree86 4.3.0.1 (Debian sarge)
Kernel 2.2 is from potato (or earlier).
Did you have a working X with same hardware with potato ?
Can you reboot into potato to try if it still works
(maybe use a knoppix disc) ?
In short :
you have a bug,
maybe X does not start, or maybe it generates incorrect timings
for now it looks like it generates incorrect timings.
this may be due to
incorrect settings in your configuration
(please try to rule this out by trying extremely conservative settings,
both conservative modelines and conservative hsync/vsync specs),
defective hardware
(please try to rule this out by trying with a different monitor,
or get same monitor/videocard to work with a different X
(potato, knoppix, latest xorg, whatever),
or get same monitor to work on a different computer
(also swap videocards if possible).),
bug in X
(no other bugreports that certainly report same thing,
and would probably be a bug for upstream,
since the vga crt-controller does work).
If hardware trouble and configuration errors can be ruled out,
then it can be sent upstream (by you or by Debian X developers).
So please experiment some more, and let us know the results.
Good luck,
Siward
(home.wanadoo.nl/siward)
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