> > * Don't use pcicfg space for other purposes than initial configuration.
> > Especially do not use it in _mode_setup() to distinguish device versions.
> > Use flags or a chipset_version field in the <meta>_t structure instead.
>
> Here is something to think about. It was recently discussed on the linux
> kernel mailing list. Their are now hot swappable pci cards. Yes you can
> plug in pci cards without rebooting the machine. I know Compaq now has
> such machines. It looks like a way to rescan the pci bus needs to be done.
> I don't know the details since I don't have the PCI specs from intel.
You don't really expect a system to save state of a graphics card or
whatsoever, keep all processes attached to it running and continuing
as if nothing happened when doing this, do you? Do you expect this
even if another brand of graphics card is inserted? Should the same driver
serve this card?
I can only imagine one case where hot-swapping can be useful: high
availability. When you have to maintain or repair a system. Then you
should have redundant devices anyway and (automatically) restarting
services after a fatal failure using the backup device is easily possible.
However, for the driver this is not different than a 'load/unload' cycle
on a normal system.
Thus hot swapping requires proper driver management in the OS. Linux has some
early version of this with the module on-demand loading. However, how to
decide a display card is not needed anymore? This can only be done by
the operator.
Hot swapping is a delicate issue. First you have to make sure that the
driver has shut down the board in question properly, then you can
indicate it's save to remove the board (there are some LED's
specified to indicate state AFAIK). However, for the lifetime of a driver
you should be save to assume the card is there and stays the same.
Otherwise the performance-over-everything mentality of the Linux people
would require some change. I don't see that happen.
Steffen
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