DOS ain't dead - Kolibri OS can chg refshrate on new NV VGA!

RayeR

CZ,
01.06.2008, 01:34

Kolibri OS can chg refshrate on new NV VGA! - usefull 4 DOS (Developers)

Hi,
I just tested a new floppy image of Kolibri OS which is BTW cool small OS but I'm interesting in another thing. It contains a small utility VRR - Vertical Refresh Rate 2.0 which can setup 800*600@96Hz on my GeFrorce 7600GS with nvidioted VBE 3.0 BIOS which normally cannot set refresh rate along standard VBE 3.0 rulez. So it would be good to lear how VRR is doing it and then make a similar DOS tool or upgrade VBEHz. Sources of VRR are available in Kolibri source package and it is menuet os FASM source. It's not much readable for me but maybe somebody else would like to check it. :-)

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DOS gives me freedom to unlimited HW access.

Laaca

Czech republic,
01.06.2008, 11:27

@ RayeR

Kolibri OS can chg refshrate on new NV VGA! - usefull 4 DOS

Post reply

Hm, the critical code is in .\drivers\vmode.asm
You are right - the code is badly readable. It seems that principle is that you set higher videomode, remember setting of some CRTC registers and then you switch to lower videomode and replace the current CRTCs with the previous ones.

However better would be to contact the author. His name is Trans and can be contacted by email on:
transafe*rambler*ru
transafe*chat*ru
trans397*yahoo*com

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DOS-u-akbar!

RayeR

CZ,
01.06.2008, 13:26

@ Laaca

Kolibri OS can chg refshrate on new NV VGA! - usefull 4 DOS

Post reply

> Hm, the critical code is in .\drivers\vmode.asm

Aha, it's completly outside VRR :)

> You are right - the code is badly readable. It seems that principle is

BTW what means MCALL? It's seen often in code, sometimes alone sometimes with some numerical args.

> that you set higher videomode, remember setting of some CRTC registers and
> then you switch to lower videomode and replace the current CRTCs with the
> previous ones.

Yes, I got this from readme. It's intersting idea/hack to preserve CRTC if they cannot(?) be set directly.

> However better would be to contact the author. His name is Trans and can

I already mailed him so hope he tell us more.

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DOS gives me freedom to unlimited HW access.

Berlin, Germany,
02.06.2008, 10:52

@ RayeR

Kolibri OS can chg refshrate on new NV VGA! - usefull 4 DOS

Post reply

> > You are right - the code is badly readable. It seems that principle is
>
> BTW what means MCALL? It's seen often in code, sometimes alone sometimes
> with some numerical args.

MCALL is a macro to call a specific MenuetOS function. It's in various macros.incs.

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Forum admin

RayeR

CZ,
02.06.2008, 11:20

@ rr

Kolibri OS can chg refshrate on new NV VGA! - usefull 4 DOS

Post reply

> MCALL is a macro to call a specific MenuetOS function. It's in various
> macros.incs.

Aha, thx for explain.

I also sent a mail to Bear Windows, hope he will not afraid of make it public

Hi, Martin!

I understand how Kolibri's driver (vrr_m) works.

1) it sets mode (for example 1024x768x32, 60hz)
2) and resamples crtc registers
3) and now you have 800x600x32, 98hz

it can downsample-

1024x768*60-->800x600*98
800x600*60-->640x480*94

What a crappy evil method to do this!!!

I make a dos-program doing this stuff, based on vrr_m,

may be I incorporate this method in VBEMP,
but it can damage or got out of sync any unsupported monitor, such as it cannot clearly control refresh rates!!!

Regards, bw.

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DOS gives me freedom to unlimited HW access.

Laaca

Czech republic,
02.06.2008, 12:39

@ RayeR

Kolibri OS can chg refshrate on new NV VGA! - usefull 4 DOS

Post reply

> I make a dos-program doing this stuff, based on vrr_m,

Wow! Give us the program and _source_ please.

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DOS-u-akbar!