Linux-kernel mailing list archive 1999-37,: Re: New Idea? Capture video settings details in Win98/etc. forXFree86

# Re: New Idea? Capture video settings details in Win98/etc. forXFree86

Stephen D. WIlliams (sdw@lig.net)
Mon, 13 Sep 1999 20:19:51 +0000

- Messages sorted by: [ date ][ thread ][ subject ][ author ]
- Next message: Alan Cox: "Re: only root has acces to /dev/mem ?"
- Previous message: Jason Clifford: "Re: Re: New Idea? Capture video settings details in Win98/etc."

Horst von Brand wrote:

> "Stephen D. Williams" <sdw@lig.net> said:
> > kernel@mail.intercomp-sys.com wrote:
>
> [...]
>
> > > Most of the hardware that windows 98 can find in your PC and SUPPORTED in
> > > Linux can be found quite easily. Try the latest distributions (Redhat
> > > Loxar, Caldera OpenLinux 2.3, SuSE 6.2 etc)
>
> > I pointed this out. Detecting the hardware all or most of the time isn't the
> > problem although sometimes detecting ram and clock settings seems
> > deficient.
>
> Finding the RAM amount depends on BIOS, some are very broken and just don't
> work, period.

Not the system, the video card!

> If you are talking RAM on the video card, that very much depends on the
> card. For many of them the information that tells you how to find that out
> just isn't available (together with the more complex stuff to really get
> the card to work).

I think it is probably possible to infer from the Win98 video mode and resolution
how much ram, at least, is available. For some chipsets that are supported by
XFree86, certain implementations (specific boards) still confuse it.

> > > Also, Windows like to mess with IRQ's, DMA's and stuff that you'll no
> > > neccsary agree to the same settings on Linux...
>
> > The dot clocks, scan frequencies, and to a lesser extent the video mode
> > are what's needed. These are the parameters that really need to be tuned
> > manually often with XFree86 because you don't have the benefit of details
> > of the particular card you have.
>
> Those are parameters that depend on your _monitor_, not your video
> card. And try to set up Win98 with an unknown monitor (i.e., a not PnP
> one)...

Actually I've had very little trouble setting up Win98 with various video cards
and misc. monitors, even generic ones.
Although it can take a little tweaking, the secret seems to be that the video
card's BIOS and/or driver set's some reasonably middle video parameters that seem
to work with typical monitors. (Of course cheap cards seem to assume cheap
monitors and top of the line cards seem to assume a top of the line video
monitor.)

With XFree86 conversely, I nearly always have to tweak, guess, and play around
with things for a while before I get it right.

Part of my guess is that it's not just the chipset core, but other card details
such as dram/gram/sdram, bus interface, clock chip, etc. that determine what the
appropriate parameters are. The BIOS/Driver combination know what works well and
XFree86 only has specific data points backed up with generalities. In other
words, the driver knows that the card in question has cut corners to lower cost,
or something, and that the chipset should be run at no more than X framerate,
etc. Conversely, a newer card/monitor combination might drastically increase the
speed compared to traditional versions of a chip and XFree86 would by default use
the more conservative configuration.

For things that are accessible, it's a way to get the benefit of the bios/driver
knowledge of what works best into Linux.

> --
> Dr. Horst H. von Brand mailto:vonbrand@inf.utfsm.cl
> Departamento de Informatica Fono: +56 32 654431
> Universidad Tecnica Federico Santa Maria +56 32 654239
> Casilla 110-V, Valparaiso, Chile Fax: +56 32 797513

sdw

    --
    OptimaLogic - Finding Optimal Solutions     Web/Crypto/OO/Unix/Comm/Video/DBMS
    sdw@lig.net   Stephen D. Williams  Senior Consultant/Architect   http://sdw.st
    43392 Wayside Cir,Ashburn,VA 20147-4622 703-724-0118W 703-995-0407Fax 5Jan1999

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.rutgers.edu
    Please read the FAQ at http://www.tux.org/lkml/

- Next message: Alan Cox: "Re: only root has acces to /dev/mem ?"
- Previous message: Jason Clifford: "Re: Re: New Idea? Capture video settings details in Win98/etc."