DR GM SEDDON posted <437F0FBC.6010908@...>, excerpted below,
on Sat, 19 Nov 2005 11:42:52 +0000:
> Hi I'm trying to configure my display. I have successfully created a
> xorg.conf file that works. However, I have tried to optimise my display
> as recommended in the manual. From 'lspci' my graphics card is
> unknown. It is an ATI radeon but I entered unknown. I have tried
> 'Screen0' and 'default screen'. When I startx I get 'unknown monitor
> type' in the log. Can anyone advise?
That's xorg trying to scan the DCC info from the monitor (as most modern
monitors should provide) and failing to get it. It's not complaining
about your graphics card (altho it's possible if it's using the wrong
driver that it won't be able to get the monitor info due to that), but
that your monitor isn't returning any info for xorg to use to set itself
The below info is for analog video cards and monitors. I'm not sure how
digital ones, lcd and the like, may differ, except that I know their
resolutions are typically lower for their size, they sell by displayed
size, not tube side, so a 19" CRT is usually about the same viewable size
as an 18" LCD (tho the LCD is lower max resolution), and they are more
expensive but not nearly as heavy or bulky! Oh, LCDs also tend to come in
widescreen ratios far more frequently than CRTs!
The good thing (within context) about LCDs is that they are newer
technology, so often a newer product, meaning it's easier to find specs
for them. If it's a laptop, look for the laptop specs, and you'll get the
video card info at the same time!
Since xfree86-4 and now with xorg, setting up monitors is generally pretty
easy, even if it can't get the info automatically, because xorg has
default resolution and timing modes that it will use, given the basics.
man xorg.conf, take a look at the monitor section, then google your
monitor (if necessary) and get the necessary specs. I've done this with
more than half dozen used monitors that needless to say I had no manuals
for, thus no from the factory specs. They are generally fairly easy to
find, once you feed google the make and model number of your monitor.
The numbers you will need:
Horizontal sync, normally in KHz. Here's the numbers from one of mine,
from xorg.conf, to give you an idea of the range. (Don't just use mine,
if it's wrong and you let the monitor go for long, it can burn it out!)
High resolutions will use near the top end. The bottom end isn't used
much any more, unless you like to use xorg's ctrl-alt-numplus and numminus
sequences to zoom, as I often do, and want to get close to the min
resolution as well.
Vertical refresh, normally in Hz. High resolutions will use lower numbers
here. The high end is the one not so often used any more. Note however
that most folks can't stand refresh rates below 60, and many need 75 or
better to be comfortable. Of course, that means you can't drive it to as
high a pixel-count resolution. Here, I can tolerate 60 Hz with dark
backgrounds and light text/foregrounds, so mostly dark. With a white
screen background, I need higher refresh rates, 68-75. Again, here's mine
to give you an idea, but don't just use mine.
Those will go in the Monitor section. You can use xorg's autosetup (there
are several choices for tools to try) to generate a basic xorg.conf, then
create or change the Monitor section as necessary.
Two option but useful numbers for the same section, if you can find them.
Dotclock, usually in MHz (maximum typically runs ~230-ish with a decent
monitor), and DisplaySize in x and y mm. xorg usually does fine without
the former if you can't find it, by using the numbers above. The latter
is only used to ensure semi-normal font sizes, otherwise various versions
may change the default font size, if they can't find it and you didn't set
it, rather drastically, for the same settings in your X environment.
Thus, it's not vital, but it's nice to have, and usually pretty easy to
find, tho you might have to do a bit of inch/mm conversion (25.4mm/inch).
The other place your monitor numbers come into play is in the Display
subsection of the Screen section, in the Modes listing. This is just a
listing of the main and any additional pixel resolutions you may desire
(that xorg agrees are possible given the settings for video card and
monitor). If your numbers are good enough, and your screen large enough,
2048x1536 is the highest practical resolution available (assuming the
standard 4x3 ratio) -- but only on 20" and larger monitors or it's
overkill. 1600x1200 is, however, often the rated maximum for the 19-22"
monitor size, and more comfortable for many, particularly as it allows a
higher refresh rate. (Monitors rated for 75 Hz refresh at their rated
maximum, however, can generally do 60 Hz at higher resolutions, if your
eyes can stand it, of course.) For a 19" monitor, 1280x920 resolution
(4x3 ratio) or 1280x1024, altho that gives you rectangular pixels. For a
17" monitor, 1280x1024 is high end, 1024x768 is standard. 15" do 1024x768
and 800x600. Old and small monitors will generally do 640x480, 800x600 if
you are lucky and can tolerate the lower refresh.
Here's one of my screen mode line entries, listing all the resolutions I
run (22" monitor, the highest normally resolution normally, lower ones for
zoom, using the zoom keys mentioned above, DisplaySize is 400x300mm, so at
that resolution, my pixels are a full mm square!). Most folks probably
don't have half that many resolutions (plus many won't want to run
2048x1536 at the refresh possible on their monitor, even if they can, so
that and the 1792 resolution won't be so common). Note that the 640x480
resolution is square pixels, the 640x400 isn't, but I have a game that
runs that, so... That one is also a custom modeline, as well, as it's not
one that xorg has preconfigured.
Modes "2048x1536" "1792x1344" "1600x1200" "1280x960" "1152x864" "1024x768" "800x600" "640x480" "640x400" "512x384" "400x300" "320x240"
It should be easy to find the maximum resolution for your monitor, as
that's one of the selling features, so even hits that don't list anything
else often list that.
Duncan - List replies preferred. No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master." Richard Stallman in
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