[PATCH 0/5] Initial DisplayPort OUI probing

Adam Jackson ajax at redhat.com
Mon May 21 14:09:41 PDT 2012


On Mon, 2012-05-21 at 16:35 -0400, Alex Deucher wrote:
> On Mon, May 21, 2012 at 4:11 PM, Adam Jackson <ajax at redhat.com> wrote:
> > I had been considering MST to be multiple CRTCs and some quasi-virtual
> > connectors.  Does that not match the hardware?
> 
> That's the basic idea.  At the hw level you have multiple crtcs and
> digital encoders feeding a single digital phy which is wired to a
> connector on the board.  The phy takes care of muxing the source
> streams.  MST works by enclosing multiple video streams (plus optional
> secondary streams like audio) into VC (virtual channel) packets.  The
> VC packets are scheduled into timeslots in the main link timing.
> Setup is via aux.  The DP bus starts to look more like a network.

Right, my question was more whether there'd be an issue with using CRTCs
and connectors as we already have them, or whether it's something new
we'd need to teach userspace about.  Certainly it might be ugly to have
DP-0.0 through DP-0.16, but functionally it doesn't seem like a big
deal.

> Additionally, you can tunnel other things like USB.  Should be "fun."

Yeah, ethernet too if the marketing material is to be believed.
Definitely going to need a more sophisticated bandwidth calculator at
minimum.  How complete is the USB support?  Like, do isochronous
transfers have to work?  They already don't work very well on real USB,
I can't imagine it working better on a contended link.

- ajax
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