Nvidia drivers unable to scale correctly

Masavishnu

I'm having trouble trying to scale the image for my LCD display. I'd like to run applications that require resolutions lower than its native (1280 x 1024) centered rather than scaled. However, the Nvidia drivers seem to think that my display has a native resolution of 1024 x 768. Using the centered option would require the use of GPU scaler, which won't work if I try to run use it at a resolution higher than what it deems to be my native resolution. The screen just remains blank.

So, nvidia-settings reports 1024 x 768 as my native resolution. If I check the 'use GPU scaler' box, the screen turns blank. I get the same result when I set the scaling option in my xorg.conf. Also, I'm unable to get 1280x1024 unless I add NoDFPNativeResolutionCheck to ModeValidation. I believe that the GPU scaler fails to operate properly due to the improperly detected LCD native resolution.

What should I do? I'm using nvidia-drivers-1.0.9775-r1.

edit: Is there a way to force the native resolution information?

whig · l33t Joined: 27 Nov 2004 Posts: 973 Location: New Zealand

Look in the X log to see why the mode you want is rejected. X can be invoked with verbose debug output too.

Masavishnu · Posted: Mon May 21, 2007 12:03 am Post subject:

whig · l33t Joined: 27 Nov 2004 Posts: 973 Location: New Zealand

Masavishnu · Posted: Mon May 21, 2007 1:43 am Post subject:

whig · l33t Joined: 27 Nov 2004 Posts: 973 Location: New Zealand

Masavishnu · Posted: Mon May 21, 2007 1:44 pm Post subject:

jschellhaass · Guru Joined: 20 Jan 2004 Posts: 341

You may need option "IgnoreEdid" if that alone doesn't work you will need to create a modeline. There is something here on modlines [url]http://gentoo-wiki.com/HOWTO_Widescreen_Resolutions_(WSXGA)[/url] and here http://www.tldp.org/HOWTO/XFree86-Video-Timings-HOWTO/

The easiest is to get the info from /var/log/Xorg.0.log.

jeff

Masavishnu · Posted: Fri Aug 24, 2007 2:38 pm Post subject:

Masavishnu · Posted: Sun Aug 26, 2007 11:03 am Post subject:

Okay, seriously, I need help.

The GPU scaling thingie seems to work if I enable all mode validation things and let the drivers determine the wrong resolution for me (1024×768). It, then, refuses, under all circumstances, 1280×1024, claiming it's too big for my display and that my display had a native resolution of 1024×768 (which it doesn't). If I disable native resolution check, I get 1280×1024 but no scaling. I tried disabling EDID altogether, but then it'd simply tell me my native resolution was 640×480, and refuses to give anything larger.

To make matters further confusing, Nvidia Windows drivers also tell me my native resolution is 1024×768, but the scaling works at 1280×1024, however.

Is there a way to force the native resolution for checks?

Masavishnu · Posted: Sun Aug 26, 2007 11:33 am Post subject:

I'm fairly sure the problem is caused by the incorrectly detected native resolution. Nvidia-settings help tells me that GPU scaling outputs the image at the detected native resolution, so I figure the problem would be solved by forcing the correct native resolution. But just how do I do that?

whig · l33t Joined: 27 Nov 2004 Posts: 973 Location: New Zealand

Add a Modeline? This would tell X a resolution (and frequencies) it can work at. I've never seen it needed to be used in the case of a LCD before - could be dangerous.

Masavishnu · Posted: Mon Aug 27, 2007 4:03 am Post subject:

Masavishnu · Posted: Mon Aug 27, 2007 6:14 am Post subject:

I'm fairly sure that the problem is indeed caused by the incorrectly detected native resolution value. As the scaler attempts to output the image at that resolution, it probably goes wild when it tries to scale DOWN e.g. 1280x1024.

So, the question is, can I enforce the drivers to think another resolution to be native? So far, I haven't been able to find a proper xorg.conf setting for that. Is there one? If there isn't, could the same be done if I used custom EDID thingie? I mean, the drivers seem to offer the option of using EDID settings stored in a file. How could I create custom settings?