Re: [PATCH] arm64: dts: mediatek: mt8188: Fix IOMMU device for rdma0

[AngeloGioacchino Del Regno]

Il 08/04/25 11:23, Chen-Yu Tsai ha scritto:
> Based on the comments in the MT8188 IOMMU binding header, the rdma0
> device specifies the wrong IOMMU device for the IOMMU port it is
> tied to:
>
>      This SoC have two MM IOMMU HWs, this is the connected information:
>      iommu-vdo: larb0/2/5/9/10/11A/11C/13/16B/17B/19/21
>      iommu-vpp: larb1/3/4/6/7/11B/12/14/15/16A/17A/23/27
>
> rdma0's endpoint is M4U_PORT_L1_DISP_RDMA0 (on larb1), which should use
> iommu-vpp, but it is currently tied to iommu-vdo.
>
> Somehow this went undetected until recently in Linux v6.15-rc1 with some
> IOMMU subsystem framework changes that caused the IOMMU to no longer
> work. The IOMMU would fail to probe if any devices associated with it
> could not be successfully attached. Prior to these changes, only the
> end device would be left without an IOMMU attached.
>
> Fixes: 7075b21d1a8e ("arm64: dts: mediatek: mt8188: Add display nodes for vdosys0")
> Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>