RE: fixed frequency monitors
On 29-Jul-01 Sam Varghese wrote:
> i managed to get two 20" monitors today - but
> both are fixed frequency.
> does anyone have any experience in getting a
> monitor of this kind to work with linux?
I've done this with Hewlett Packard A1079C monitors.
These have a 3-line input with separate cables for
Red, Green and Blue, the synchronisation signal
goes on the Green channel, and the resolution is
fixed at 1280x1024. In this case the main issue is
coping with the sync-on-green.
The only way I found was to install a Matrox Millennium
board (though maybe there are others that support
sync-on-green, but I haven't found them). Then you have
to edit your XF86Config file so as to
a) Get the monitor frequency, etc., right;
b) Ensure that the device section has the sync-on-green
option set.
In the case of the HP A1079C and the Millennium (4MB)
board, the relevant sections of XF86Config are:
Section "Monitor"
Identifier "HP 1280x1024-72Hz"
VendorName "Hewlett-Packard"
ModelName "A1097A"
BandWidth 135
HorizSync 78.125
VertRefresh 72.008
Mode "1280x1024"
DotClock 135.00
HTimings 1280 1344 1536 1728
VTimings 1024 1027 1030 1085
EndMode
EndSection
Section "Device"
Identifier "Matrox Millennium"
VendorName "Matrox"
BoardName "MGA"
Option "sync_on_green"
EndSection
Section "Screen"
Driver "svga"
Device "Matrox Millennium"
Monitor "HP 1280x1024-72Hz"
Subsection "Display"
Depth 24
Modes "1280x1024"
ViewPort 0 0
EndSubsection
EndSection
That's all that's needed, and I find it works fine in X (those
ancient monitors have a great display: sharp, undistorted,
steady, good colours, and lots of pixels).
If your monitor is not the same, you will have to find the
right settings for the Section "Monitor" -- these are fairly
critical. And if the resolution is different, you will have
to also change Section "Screen". You may well be able to
locate the appropriate parameters by doing a Web search
on monitor make/model plus "linux". For instance, I got a lot
of useful stuff with a Google search on
"HP-A1079C" AND "linux"
You may even find suitable settings tucked away in the "monitors"
database in XFree86, which in my case was in the file
/usr/X11R6/lib/X11/doc/Monitors
where you find
#Date: Fri, 16 Sep 1994 23:16:32 -0700
#From: "Leonard N. Zubkoff" <lnz@dandelion.com>
Section "Monitor"
Identifier "HP 1280x1024-72Hz"
VendorName "Hewlett-Packard"
ModelName "A1097A"
BandWidth 135
HorizSync 78.125
VertRefresh 72.008
Mode "1280x1024"
DotClock 135.00
HTimings 1280 1344 1536 1728 VTimings 1024 1027 1030 1085
EndMode
EndSection
NOTE: As I say, it works fine in X. However, it won't work in text
mode since it's not getting the sync-on-green (which isn't started
up until X starts). All I get in text mode is shimmering horizontal
lines, and I suspect one is stuck with that in Linux (though I believe
there are drivers, but not for Linux, which can set the sync-on-green
for all modes). So in that case I either boot up with the monitor
switched off, start X "blind", and then switch it on; or I can telnet
in from another machine.
Possibly some other card may allow sync-on-green to be set by jumpers.
The other thing to bear in mind is that the Apple Mac monitor works
exactly the same (sync-on-green), but you can buy PC->Mac adapters
(plug the adapter into the PC video port, and then the monitor cable into
the adapter) which route the PC sync output onto the Mac green line, and
then it should work in all modes. Could be worth a try for your monitor.
Hoping this helps,
Ted.
--------------------------------------------------------------------
E-Mail: (Ted Harding) <Ted.Harding@nessie.mcc.ac.uk>
Fax-to-email: +44 (0)870 167 1972
Date: 29-Jul-01 Time: 11:02:48
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