Gentoo Archives: gentoo-amd64

From: Duncan <1i5t5.duncan@×××.net>
To: gentoo-amd64@l.g.o
Subject: [gentoo-amd64] Re: unknown monitor
Date: Sat, 19 Nov 2005 13:19:11
In Reply to: [gentoo-amd64] unknown monitor by DR GM SEDDON
DR GM SEDDON posted <437F0FBC.6010908@×××××××××××××.uk>, 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? > Gavin
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 up. 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. HorizSync 30-110 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. VertRefresh 50-180 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 -- gentoo-amd64@g.o mailing list


Subject Author
Re: [gentoo-amd64] Re: unknown monitor DR GM SEDDON <gavin.m.seddon@×××××××××××××.uk>