Re: [PATCH v6 5/6] arm64: dts: qcom: Add device tree for Nord Ride board

[Shawn Guo]

On Mon, Jul 20, 2026 at 10:40:09AM +0200, Konrad Dybcio wrote:
> On 7/20/26 6:20 AM, Shawn Guo wrote:
> > On Thu, Jul 16, 2026 at 07:14:56PM +0200, Konrad Dybcio wrote:
> >> On 7/16/26 4:26 PM, Shawn Guo wrote:
> >>> From: Deepti Jaggi <deepti.jaggi@xxxxxxxxxxxxxxxx>
> >>>
> >>> Add initial device tree for the Qualcomm SA8797P Ride reference board,
> >>> which is built on Nord GearVM variant.
> 
> [...]
> 
> >>> +&scmi15 {
> >>> +	status = "okay";
> >>> +};
> >>> +
> >>> +&scmi23 {
> >>> +	status = "okay";
> >>> +};
> >>
> >> Why only these ones? Can all of the SCMI servers be enabled?
> > 
> > These are the ones that have actual/enabled client/consumer devices,
> > e.g. scmi3 for ufs, scmi11 for uart, scmi23 for thermal sensors.
> 
> We normally refrain from enabling resources in the DT only because the
> OS (really just Linux) doesn't have the necessary support to cope with
> the ""complete"" system description. In this case, there's a firmware
> layer drives everything and handles on/off requests gracefully
> (hopefully).
> 
> > We can enable all the SCMI servers, but I'm afraid that cause kernel
> > to map shared memory and issue SMC calls to discover protocols (like
> > power domains, DVFS, resets) that have no consumers, which might waste
> > a small amount of memory and boot time.
> 
> Please give it a shot and see if there's any immediate
> problems.

Sorry! I have to take "We can enable all the SCMI servers" back. I just
tested. It seems that NHLOS ABL doesn't like the idea, and it
fails/refuses to boot Linux Kernel when we enable all SCMI instances in
DT.

I can try to figure out the cause by working with Auto/firmware team
internally, but that likely takes some time. Can we address this later
as a separate topic, so that the whole series doesn't get blocked
for v7.3 merge window?

Shawn