Re: [PATCH RFC 0/4] iommu/arm-smmu-v3: Support shared Stream IDs

[Jason Gunthorpe]

On Fri, Sep 18, 2026 at 07:48:34PM +0800, Peng Fan wrote:

> However, the DMA channel case was just one example - the shared-SID
> need exists independently of it. Our SoC (i.MX95) has only 64 SIDs
> total, serving MMC, SD, NET, PCI, DMA, NPU, DSP, DISPLAY and more.
> Some of these are genuinely separate platform devices (distinct DT
> nodes, distinct drivers) that share a SID by hardware design because
> the SID space is exhausted.
> 
> That cross-IP case cannot be solved by DT restructuring - the devices
> really are separate. Would you be open to reviewing the shared-SID
> SMMU support (patches 1-4) on that basis, independent of the DMA
> channel question?

I think you should revise your commit message/cover letter to focus on
something that is not a DT abuse and try again 

IIRC Robin said the SID aliasing was a PITA on SMMUv2 so it
really needs to have a strong reason.

Jason