Anyone able to set 640x240 resolution in linux on ati or nvidia?

[chessiv]

Hooking up to a 15khz monitor and xorg.conf is ignoring the modeline for it.  It takes a custom 640x480 modeline but ignores the 640x240.

[MonMotha]

Check the X server's log file.  During startup, it should emit a message indicating why it is ignoring the mode line.  Note that if you do not specify a hsync range for your monitor, and none is provided via EDID (which an arcade monitor doesn't do), it will default to a range that won't go below about 30-31kHz, which means 640x240 won't work.

For xorg, you probably have /var/log/Xorg.0.log for your log file.

Note tht 240 lines is a bit cramped if you want to use that for your desktop.  Try using an interlaced 640x480 mode.  That'll give you a lot more room at the expense of some motion artifacts from the interlace which shouldn't be too objectionable.

[chessiv]

I wasn't specifying the horizsync and vertrefresh in my xorg.conf.  What would be good settings for a 15.7 cga monitor?

Also, seeing the desktop isnt an issue since this will only be running one game.

Thanks for the help.

[chessiv]

It also looks to me like xwindows won't allow any mode outside vesa standards.  Which 640x240 doesnt appear in the standards list it seems.

[MonMotha]

It most certainly will allow non-VESA standard modes.  I've got a Matrox G100 that I run at 1440x480 interlaced (NTSC compatible) all the time.  That is decidedly NOT a VESA standard mode, nor do my timings conform to VESA GTF.

For a standard res monitor, 49-61Hz is usually a valid vertical sync range, and 14.8-15.75kHz is usually a valid horizontal sync range.  If you specify those, then X will only attempt to use modes that meet those specifications (none of the built-in VESA modes does, so it'll probably bail if you don't have a modeline).  The easiest thing to do is grab the VESA GTF based 640x480 modeline, half the pixel clock (the first number) and put "Interlace" at the end to get 640x480 interlaced, at ~15.25kHz.

If you REALLY want 640x240 for a game or something (that will be pretty much unusable as a desktop), it should accept that as well.  You'll have to work out your own modeline, but the GTF should still give valid results.  Just make sure that the hsync ends up being in the neighborhood of 15kHz and is in the range you specified.  A 240 line (+some blanking/sync), 60Hz mode will need to be progressive to hit 15kHz.

Again, CHECK YOUR LOGS to see why it is invalidating your modeline.  It usually very clearly tells you (hsync out of range, pixel clock too high/low, math doesn't work out, etc.).

[MonMotha]

Oh, FYI, the reason for my choice of 1440x480 on the G100 is that the G100 cannot do 720x480 (DVD res) at 60Hz interlaced because the pixel clock is actually too low.  Doubling the horizontal resolution doubles the pixel clock without changing any of the timings as far as the monitor is concerned.  It is then possible to do a 2:1 scale (which is quick and sacrifices no image quality at all as you just duplicate each pixel) to 1440x480, and then the monitor displays it at the correct screen aspect ratio.  The extra pixel transitions, if I were to use them, would likely be outside the input bandwidth of most SD monitors, anyway.

IIRC, one of the nvidia drivers (either the binary one from nvidia or the opensource 2d only one from the Xorg project) enforces an arbitrary limit on the pixel clock of some nvidia cards.  This will cause it to improperly reject some low-resolution modes.  There is a workaround, but it's usually easier to just use the other driver.  This also may have been fixed by now.

[chessiv]

Honestly.  I've check my log file:

/var/log/Xorg.0.log a number of times and it doesnt even mention the modeline.  Which I think is really screwy.  Unless I'm not checking the right place. 

[chessiv]

Ok, I did find the error.  It was really cryptic and didn't mention the modeline but when I commented the modeline it went away

displaygetsetmodetimingoverride failed

[MonMotha]

Just post your whole log file as an attachment.  There's almost always something in there.  That'll also give me just about every piece of info I need to know about yor hardware.

Are you using the "nv" (the 2D only one that ships with X.org) or the "nvidia" (3D one from nvidia's webste) driver?  The "nv" driver tends to give more information abou the decisions that it makes, but it also tends to be more conservative about what it will force the hardware to do.  If you've tried only one, try the other.

[chessiv]

Both the config and log file are attached.

I have one monitor setup for coding the e17.  And the other for the arcade monitor standard res wells gardner.  The 640x480 modeline works great of the wells gardner.  Still no luck with the 640x240.  I've tried 20 some modelines.  The one thats in there now was created by gtf.

Thanks for all your help