On Tue, Oct 27, 2026 at 12:42:32PM +0900, Mikko Perttunen wrote: > > This page-side use predates the series, so the fault is not itself a v2 > > regression. Is dma_buf_sgt_attach() valid for this call site, or does Tegra > > need a page/physical mapping type first? > > Sounds like a bug in TegraDRM; we should be using the DMA addr/length > for the explicit IOMMU mapping as the sgt attachment is for the dummy > DRM device explicitly intended to give us physical addresses.
No, you cannot connect dmabuf to an iommu_domain. It is 100% always illegal. DMABUF does not support this. Do not pass sg_dma to iommu functions either. > I'm currently in the process of removing the whole explicit IOMMU path > so if this only occurs with CONFIG_DMABUF_DEBUG enabled, I don't think > there's a pressing need to fix this before then. Yes I think this is probably the only way to fix it :| You have to always use the DMA API Jason
