Re: [PATCH v2 2/2] arm64: dts: qcom: kaanapali: fix traceNoC probe issue

From: Leo Yan

Date: Wed Jun 24 2026 - 11:16:23 EST


On Wed, Jun 24, 2026 at 11:08:32PM +0800, Jie Gan wrote:

[...]

> > Why does it fail ? power management ? hw broken ? Is it really AMBA or
> > do you pretend that to be an AMBA device by faking the CID/PID?
>
> The CID reads as 0 from the register, which I suspect is a hardware design
> issue. I have not yet confirmed this with the hardware team. As a
> workaround, I provided a fake periphid via a DT property to bypass
> amba_read_periphid.
>
>
> Leo commented in other thread:
> >>tnoc.c registers both an AMBA driver and a platform driver. Shouldn't >>it
> >>be registered as a platform device instead?
>
> The platform driver is intended for the interconnect TraceNoC device and is
> not designed to allocate an ATID. The issue is that the TPDM device borrows
> the ATID from the TraceNoC device, resulting in the ATID always being 0 when
> associated with an interconnect NoC device.
>
> However, I believe it is acceptable to allocate an ATID for the itNoC device
> and the issue can be fixed with this way.

I think so.