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On Sat, 28 Mar 1998, Kyle Cronan wrote:

>> Just so I understand this better, what exactly would have to go in the
>> kernel for it to be able to restore text mode in this sort of
>> situation,
>> or perhaps if it is given some kind of keyboard signal.
>
> Something maybe like a /dev/graph, and:
>
> X: open /dev/graph
> X: ioctl(fd, GRAPH_SET_MODE, MODE_1024_768_32)
> X: CRASH!!!!!! (or kill -9) implicit exit() implicit close
> (dev_graph_fd)
> kernel: ooh usage count on /dev/graph is 0 and we're still in gfx mode
> kernel: better tell the driver to revert back to textmode
> gfx driver: no problem, I know how to go MODE_1024_768_32 ->
> MODE_TEXT_80_25
>
>
> Sounds nice doesn't it?
>
> Chris

That is *EXACTLY* what KGI does. Userspace/kernel interface via
/dev/graphic device files, ioctl() for mode setting, insecure acceleration
calls, etc. "Safe" acceleration calls (on decently designed hardware
where diddling the registers won't lock the bus or fry the card) are
exported into userspace for speed. When an app shuts down, the kernel
reverts console to starting video mode. Secure attention key that kills
all processes associated with current virtual terminal and gets the
input/output hardware into a sane state.

Yes, it is nice.

Peter Amstutz

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