Re: [PATCH v2 05/16] dt-bindings: display/msm: dp-controller: Add SM8750

[Abhinav Kumar]

On 2/24/2025 7:14 PM, Dmitry Baryshkov wrote:
> On Mon, 24 Feb 2025 at 20:59, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
> > On 2/19/2025 9:08 AM, Dmitry Baryshkov wrote:
> > > On Wed, Feb 19, 2025 at 06:02:20PM +0100, Krzysztof Kozlowski wrote:
> > > > On 17/02/2025 19:58, Dmitry Baryshkov wrote:
> > > > > On Mon, Feb 17, 2025 at 05:41:26PM +0100, Krzysztof Kozlowski wrote:
> > > > > > Add DisplayPort controller for Qualcomm SM8750 SoC which so far looks
> > > > > > fully compatible with earlier SM8650 variant.
> > > > >
> > > > > As that became a question for QCS8300, does SM8750 also support exactly
> > > > > two MST streams?
> > > >
> > > > v1.5 of DP (starting from SA8775p , then SM8650 and SM8750) support 4x
> > > > MST for DPTX0 and 2x MST for DPTX1.
> > > >
> > > > The DP in SM8650 and SM8750 are identical, according to datasheet (v1.5.1).
> > >
> > > Hmm. This also means that QCS8300 is compatible with SM8650. I'll let
> > > Abhinav comment here.
> >
> > DP version by itself is not a good measure of whether the controller can
> > support 4 streams or not.
> >
> > Firstly, sm8650/sm8750 do not have a DPTX1 so we are only discussing
> > about DP TX0.
> >
> > Coming to the QCS8300 Vs sm8650/sm8750, even though the DP controller
> > version is the same, there is no HW support for more than 2 streams on
> > sm8650/sm8750 because there are no INTF blocks to drive 4 streams.
> >
> > On sm8650/sm8750, only INTF_0 and INTF_3 can be used for DP. Hence 2
> > streams.
> >
> > Whereas on Monaco, we have INTF_0, INTF_3, INTF_6 and INTF_7 capable of
>
> No idea what Monaco is, most likely it is some platform. Please use
> SoC names in public.

Monaco is indeed QCS8300. I usually do use SoC names, in this instance 
just intuitively ended up using the internal one as I use it often.

> > driving DP. Hence 4 streams.
> >
> > Let me know if there are more questions.
>
> How many stream clocks are present on those platforms? I'm asking
> because there is a small, but not non-existing difference between 'DPs
> are not completely compatible / the same' and 'DPs are fully
> compatible but different DPU blocks impose different restrictions on
> the number of MST streams'.

I have confirmed this internally. sm8650/sm8750 have only 2 stream 
clocks and not 4.