please explain to me why video/bios shadowing must be disabled to use graphics...
Hello.
Quoted 4 lines · phrostie
Quoted 1 line
not support this video card and does not open up enough ports.
what ports?
could you expand on this part?
i have a S3
For S3 cards you must not worry about this issue at all. Setting $_chipset="s3" worked for my S3 Trio flawlessly both for VGA and VESA modes. Don't remember about setting $_chipset="plainvga", but I think it could work as well.
This problem exists only on some (modern?) cards for VESA modes, but for VGA modes there must be no such problem at all (Bart, do you really have any examples when this is a problem even for VGA? Correct me then, please).
To verify if you have this "port" problem, just start your DOS prog under WinNT. If it can't set mode also there, then yes, you have this problem (I bet you don't have it with S3 though). Unfortunately opening the ports doesn't always
help: still no VESA modes on my Radeon7500, but VGA works perfectly. Thinking about returning my old S3...
Quoted 4 lines · Stas Sergeev
This problem exists only on some (modern?) cards for VESA modes, but for VGA modes there must be no such problem at all (Bart, do you really have any examples when this is a problem even for VGA? Correct me then, please).
Well VGA only uses standard ports so the only problem is to pass the VBIOS initialization in the first place, that is executing the code at c000:0003 (or c800:0003, whereever the VBIOS is). On some graphics cards this init routine requires additional open ports and maybe even accessible MMIO.
Some people reported black screens, or even machines hanging which happens when the VBIOS init routine is called.
I'm not sure why this VBIOS init routine is always called if you set $_graphics, but at least it gets the video card into a clean state. This is esp. important if you use fbdev graphical textmodes on the console instead of the standard VGA textmode (80x25).
Maybe by just bypassing the VBIOS init you can avoid this problem; I just have never looked into that possibility.
The VBE 2.0 spec defines a protected mode interface - if DOSEMU would use that it could ask which ports should be used and opened. However it does not currently use that interface, I don't know how to do that and am not able to test it anyway (being far away from my desktop where I could take some risks).
Bart
an update i did finally get dosemu working.
i can run EZ cosmos, commander keen 1-3, and battle chess. commander keen 4 and above still lock up. i did notice that the startup windows are reporting no or low memory.
Quoted 35 lines · Bart Oldeman
Quoted 4 lines · Stas Sergeev
This problem exists only on some (modern?) cards for VESA modes, but for VGA modes there must be no such problem at all (Bart, do you really have any examples when this is a problem even for VGA? Correct me then, please).
Well VGA only uses standard ports so the only problem is to pass the VBIOS initialization in the first place, that is executing the code at c000:0003 (or c800:0003, whereever the VBIOS is). On some graphics cards this init routine requires additional open ports and maybe even accessible MMIO.
Some people reported black screens, or even machines hanging which happens when the VBIOS init routine is called.
I'm not sure why this VBIOS init routine is always called if you set $_graphics, but at least it gets the video card into a clean state. This is esp. important if you use fbdev graphical textmodes on the console instead of the standard VGA textmode (80x25).
Maybe by just bypassing the VBIOS init you can avoid this problem; I just have never looked into that possibility.
The VBE 2.0 spec defines a protected mode interface - if DOSEMU would use that it could ask which ports should be used and opened. However it does not currently use that interface, I don't know how to do that and am not able to test it anyway (being far away from my desktop where I could take some risks).
Bart
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Signature · 4 lines
Oh, I have slipped the surly bonds of DOS, and danced the skies on Linux silvered wings. http://pfrostie.freeservers.com/cad-tastrafy/ http://www.freelists.org/list/cad-linux
thanks to all for the responses.
last night i was going thru the different runtime options, but regardless of what i try i still can't seem to get any of my VGA stuff working again.
under video it asks for video address.
where do i get/verify this for my card?
Quoted 16 lines
For S3 cards you must not worry about this issue at all. Setting $_chipset="s3" worked for my S3 Trio flawlessly both for VGA and VESA modes. Don't remember about setting $_chipset="plainvga", but I think it could work as well.
This problem exists only on some (modern?) cards for VESA modes, but for VGA modes there must be no such problem at all (Bart, do you really have any examples when this is a problem even for VGA? Correct me then, please).
To verify if you have this "port" problem, just start your DOS prog under WinNT. If it can't set mode also there, then yes, you have this problem (I bet you don't have it with S3 though). Unfortunately opening the ports doesn't always
help: still no VESA modes on my Radeon7500, but VGA works perfectly. Thinking about returning my old S3...
Quoted 4 lines
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phrostie
Oh I have slipped the surly bonds of DOS
and danced the skies on Linux silvered wings.
http://pfrostie.freeservers.com/cad-tastrafy/
http://www.freelists.org/webpage/cad-linux
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