Current support and roadmap for discrete graphics card hot switching

[Glynn Clements]

Stephane Marchesin wrote:

> and if you want to keep your session in between, we lack
> - X.Org infrastructure to hand a session from a graphics driver to
> another (there are a million of possible problems here)

Right; like a million display parameters which a client can query, but
for which there is no mechanism to request notification of changes,
and thus are (implicitly) constant over the lifetime of the client.

I know that the X developers don't consider incompatible changes to be
completely out of the question, but if you're talking about a
particular screen suddenly changing e.g. its glGet* values, I don't
see that happening.

And I don't think that it's realistic for the server to expose a
single set of parameters for two very different graphics chips.

It's more realistic to treat this as a traditional multiple-"Screen"
setup, with the ability to enable and disable screens. Obviously,
windows would have to either be opened on the appropriate screen
(programs which need the 3D GPU on the screen which has one), or the
application/toolkit would need to explicitly provide migration.

-- 
Glynn Clements <glynn at gclements.plus.com>