Re: [forum] How about running X on top of something else?

[Alan Cox <alan@redhat.com>]

> > > As for PCI access, our SNAP drivers do all their own PCI enumeration and
> > > XFree86 does it's own, and they coexist very peacefully.
> 
> > And I take it both have the same inability to handle hot plug still ?
> 
> Bah.  We don't relocate resources unless we need to.  So that ball's as
> much in your court as it is in ours.

Any X reassignment of PCI resources is unsafe in Linux 2.4, and going to
get more so. The DGA comemnt applies here the other way around - you don't
currently have a way to get the kernel to do the work for you. We need to
address that. X doesn't know enough hw issues or locking

> As to hot-plugging video adapters, very few of them, if any, can handle it
> anyway.  And I don't see hot-plug as a high priority for the likes of ATI
> and nVidia.

My extreme hotplug test set for 2.5.66 + rmk patches is a ten head hot
plugged video setup including 2 quad head S3 cards and a pair of C&T
cards. Total ebay cost < $400. (Kudos to the X guys - XFree86 4.3 can't
hotplug this lot but it can run it)

My off the shelf example is the mobility cardbus docking station which
has a hotplug ATI rage. Our framebuffer drivers can handle some of these
hot docks. A voodoo2 in a thinkpad docking station works correctly kernel
side. The kernel also has the framework to report new PCI devies to XFree86
as well as device removal.

Alan