On Thu, Aug 29, 2013 at 5:54 AM, Rob Clark <robdclark@gmail.com> wrote:

I guess if you have multiple encoders + multiple connectors for the
"ganging" case, then it probably just looks like 2x displays, and
nothing more really needed?

I'm a bit fuzzy on what the hw looks like in this "ganging" scenario,
so I'm not completely sure what the best approach is. But if we do
have hw like this, then it makes sense to support it *somehow* in KMS.

I don't have the hardware anymore so this is all working from memory, it didn't look like two independent displays. You had to explicitly set up connections between the two mixers to deal with things like scaled overlays that spanned both mixers (there was some in-hardware magic to make sure there wasn't a visible seam where the two mixers met).