Basic Text Mode (was: Re: Question about SysRq)

["Thorsten Glaser Geuer" <eccesys@topmail.de>]

> Thought, i really love all sysrq properties of linux, so i need less often
> to make hardware resets an then await and fear, what fsck will print.

101% ACK

> One more property, that i'd like to have should be request key to force the
> most basic text mode (say 80x25) on the console, when eg. X freezes and 
> i kill its session, then last gfx mode resides on the screen and see no way 
> to restore back the text mode - /usr/bin/reset or something alike will not 
> do it. But it seems to be not a good idea at all, does it ? 

It is a very good idea, and to implement quite easy. You just do have to
diff between three types of video cards (MDA, MGA and HGC vs. CGA and AGA vs. EGA+).
Then you do direct register writes. For the HGC I did it recently in a DOS proggy
which switched from text to gfx and back. I had a TSR which simulated a gfx BIOS.
Only problem is, I lost the source. But I could rewrite and test it on request.
I even would put it under GPL for the kernel (normally this is a no-no for me),
just ask me. I will write it in NASM then because I can't the AT&T syntax.
For non-i386 Platforms I do not know about this topic. (IIRC the Apples didnt
even have a text mode)
Maybe I could look up the EGA register values somewhere.

-mirabilos