Re: Using wsdisplay from the Xserver

[nathanw%MIT.EDU@localhost (Nathan J. Williams)]

der Mouse <mouse%Rodents-Montreal.ORG@localhost> writes:

> No, not "support [the] hardware".  I'm not proposing to mvoe the X
> server into the kernel.  Just support _access to_ the hardware.

From the perspective of INSECURE, though, the effect is the same, since
part of what you're providing access to is the video hardware's various
and sundry DMA engines (INSECURE is different from a notional
INAPPROPRIATE_ABSTRACTION_BARRIERS option....).

> If the X server needs to access certain areas of the video card's PCI
> resources because that's where the hardware keeps stuff, that's fine.
> But that's no reason it should be able to access anything else -

And this is exactly what Michael is trying to make work.

> it's also no reason it should know or care that they're _PCI_ ranges,
> rather than SBus or what-have-you.  For the X server to be even looking
> at /dev/pci* means that there's something that badly needs moving from
> the X server into the video hardwre's device driver.

Besides the points made about video drivers and kernel bloat, I suspect
there's a lot of history here about kernel developers and X developers
wanting to stay in their own domain to make things work (particularly in
ancient history, when someone hacking on X wouldn't expect to be able to
even look inside, much less modify, the OS kernel, and would use
whatever loophole like /dev/mem they could find).

        - Nathan