[RFC 0/4] Atomic Display Framework

[Rob Clark]

On Thu, Aug 29, 2013 at 7:34 PM, Greg Hackmann <ghackmann at google.com> wrote:
> On Thu, Aug 29, 2013 at 5:54 AM, Rob Clark <robdclark at 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).

Ok, sounds like mixer == crtc (ie. the thing the combines one or more
planes)?  So it sounds maybe a bit like:

 plane0_0 -\
    ...    +---> CRTC -\
 plane0_n -/           |
                       +--> encoder -> connector
 plane1_0 -\           |
    ...    +---> CRTC -/
 plane1_n -/

?

BR,
-R