Number of MST displays for Radeon RX 4xx / RX 5xx ?

[Alex Deucher]

On Mon, Mar 18, 2019 at 6:50 AM Klaus Kusche
<klaus.kusche at computerix.info> wrote:
>
>
> Hello,
>
> I was unable to find any documentation (neither on the amd side
> nor on the linux side) giving the maximum number of independent displays
> supported by the amd polaris GPU's.
>
> The old cape verde GPU supports six displays,
> either with cards having 6 separate DP outputs or with MST hubs.
>
> But for polaris, the maximum number of outputs I've seen on graphics cards
> is 5 for 570 / 580 / 590, and 4 for 560 & WX 4100, and 3 for 550 & WX [23]100.
> There seems to be no card with 6 outputs.
>
> https://www.x.org/wiki/RadeonFeature/ says
> "Max Supported Displays (Eyefinity)" "4-6" for these cards,
> but it does not tell which ones are only 4 or 5 and which ones are 6.
>
> How many displays can be connected (in linux) to these cards using MST hubs,
> especially to the smaller ones WX [234]100 ? Also 6 for all cards?
>
> Many thanks for your help!

Polaris 10 has 6 display controllers and Polaris 11 and 12 have 5
display controllers.  The numbers of displays supported on an MST link
(and in general) is limited by the bandwidth requirements of the
connected displays, bandwidth capabilities of the GPU, and the number
of type of physical connectors on the board itself.

Alex