From: rogers@isi.edu (Craig Milo Rogers) Subject: Re: How to switch back to VGA-text from SVGA-text mode??? Date: 27 Mar 1993 07:16:28 GMT
In article <csaba.4.733195427@vuse.vanderbilt.edu> csaba@vuse.vanderbilt.edu (Csaba A. Biegl) writes:
>>Because nobody has bothered to write to interrupt handlers in protected-mode
>>to run real-mode code. It certainly CAN be done, only those who want it don't
>>have enough knowledge about 386 programming, whilst those who know have a
>>religious thing about not supporting the BIOS :-)
>
>There is on more thing to consider: most SVGA cards come with some clock
>tweaking, image centering TSR-s that you have to install in your
...
>order to be compatible with any monitor. It is the TSR which augments and/or
>takes over the mode set INT 10H BIOS call to provide higher refresh rates
>and non-interlaced modes.
...
>For the majority of the cards the BIOS interface would be useful only if
>Linux booted from DOS AFTER you had a chance to install your video TSR.
>Furthermore, the Linux kernel would have to keep a copy of the low memory
>where the video TSR was installed. It's getting more complicated, doesn't it?
Um, would it be possible to startup a dosemu-controlled
process, map the video BIOS (and any video memory), enable privileged
I/O to the video ports, then run the video TSRs and setup programs? I
haven't yet acquired Linux (I'm still using an 8088!), so I can't
answer this question directly. I suppose that dosemu might need a
change or two to support this. Any comments?
Craig Milo Rogers