DOS ain't dead

nVidia-disable LCD scaling, refresh rates (Users)

posted by RayeR , CZ, 07.01.2009, 14:54

Hi,
after a long years I finally moved from CRT to LCD. I know about many many LCD disadvantages but my 8-year old Samsung is fading and there are no new CRTs available, only refurbished. It was hard for me to choose good enough LCD. Finally I chosen NEC 2190Uxp. It has S-PVA panel, 12bit gamma LUT, and lot of features. For me is interesting user defined scaling and 1:1 option for each resolution. But it's not so simple...

I'd like to use DVI-D connection to my nvidia 7900GT for best quality image. But unfortunatelly my vnidioted bios have some bad behavior which complicate it.
1) it's enabled on-chip upscaling by default, so my monitor always get 1600x1200 regardless on current videomode - this mean I cannot use LCD resampling and 1:1
2) for unknown reason when DVI is attached VESA BIOS will drop 1600x1200 and higher VESA modes from mode list - this really sucks! I wondered where my hires modes get lost and when I connected LCD via analog they came back.

So currently I have LCD attached by both cables to 2 heads on VGA and I can switch between analog and DVI. It's interestng that when windows has load nvidia drivers that on-chip scaling is disabled and I can use LCD scaling or 1:1. Of course via analog cable it works anywhere. It seems that this nvidia feature is configurable. I guess that setting some MMIO register will be eneough but nvidia don't give docs. But there's opensource nvidia linux driver http://nouveau.freedesktop.org/wiki/ which makes progress. I chat with some guys on IRC and they told me that this scaling feature is already implemented in nouveau driver. My plan is to browse sources and get knowledges to write own DOS utility which will disable scaling. If there is somebody interested let me know.

Second problem is disabled VESA modes. I will probalby need DASM and hack the VGA BIOS. If somebody can tell me something about nvidia bios structure or know where to find it please let me know.

Another thing is releated to refresh rate control. I personally lost interest because LCD doesn't need higher refresh rates :) but Bear Windows (autor of VBEMP) mailed me that he succeed with setting refresh rate and he plan to add support to his drivers. Maybe he could make some DOS tool too. He used same approach as colibri os driver. Or maybe he give me some sample code for others who want to make a DOS refresh rate tool.

---
DOS gives me freedom to unlimited HW access.

Complete thread:

• nVidia-disable LCD scaling, refresh rates - RayeR, 07.01.2009, 14:54 (Users)
  • nVidia-disable LCD scaling, refresh rates - rr, 07.01.2009, 20:25
    • nVidia-disable LCD scaling, refresh rates - RayeR, 08.01.2009, 00:45
      • nVidia-disable LCD scaling, refresh rates - RayeR, 12.01.2009, 10:04
        • nVidia-disable LCD scaling, refresh rates - RayeR, 15.01.2009, 12:21
  • nVidia-disable LCD scaling, refresh rates - Laaca, 07.01.2009, 21:21
    • nVidia-disable LCD scaling, refresh rates - RayeR, 08.01.2009, 00:49
      • VBE3TEST - RayeR, 09.01.2009, 02:38
        • VBE3TEST - RayeR, 09.01.2009, 11:49
        • VBE3TEST - Laaca, 10.01.2009, 12:02
          • VBE3TEST - RayeR, 10.01.2009, 23:26