radeon/r200 color tiling ddx / drm questions

[Roland Scheidegger]

Ian Romanick wrote:
> Roland Scheidegger wrote:
> 
>> The dri and drm seem fairly straightforward, though I'm not sure the way
>> I handled communication between especially drm and ddx is how it's meant
>> to be. dri got a bit unlucky, as ddx can't know at startup if it will be
>> able to handle color tiling, so old dri together with new drm and new
>> ddx will not work (correctly) (if you have enabled color tiling). All
>> other combinations should however work if I didn't forget something.
> 
> 
> If an "old" {radeon,r200}_dri.so is completely incompatible with the new 
> DDX, you need to bump the major version.  When that happens the DRI 
> driver will bail when you try to load it.

It is not really completely incompatible - only when color tiling is 
enabled (and it wouldn't crash or something like that, just display 
garbage).
Also, when bumping the ddx major version, it would mean that a new dri 
driver now no longer works with the old ddx - which is not desired 
behaviour since there is no reason at all why it couldn't run with an 
old ddx (though we could just do the version check twice I guess, that 
might print some very confusing warnings but probably should work).
Bumping ddx major version also seems to be quite a drastic solution, 
from an architectural point of view there really are no major (actually, 
not even minor) changes involved. Something like a sane memory 
management imho would more warrant a version bump...

Roland