Re: [PATCH v2 01/23] dt-bindings: display: msm: Add Qualcomm DCP

[Rob Herring <robh@kernel.org>]

On Wed, Nov 11, 2026 at 12:40:05PM +0530, Jayant Shekhar wrote:
> 
> On 27-10-2026 01:14, Rob Herring (Arm) wrote:
> > On Mon, 26 Oct 2026 11:51:11 +0530, Jayant Shekhar wrote:
> > > DCP platforms place the display pipeline under firmware control, so Linux
> > > cannot discover display resources through direct register access. The DRM
> > > driver therefore needs device-tree descriptions of the Qualcomm transport
> > > wrapper, display topology, IOMMU contexts, and panel connections.
> > > 
> > > Add bindings for the Qualcomm DCP transport wrapper and VirtIO display
> > > subsystem. Document the IPCC power-notify resources, transport and
> > > framebuffer IOMMU contexts, firmware-visible IOVA range, INTF graph, and
> > > DSI panel connections. The wrapper creates a standard VirtIO-MMIO child
> > > after the IPCC power-notify sequence has completed.
> > > 
> > > Assisted-by: LLM
> > > Signed-off-by: Jayant Shekhar <jayant.shekhar@oss.qualcomm.com>
> > > ---
> > >   .../bindings/display/msm/qcom,dcp-dsi.yaml         |  79 ++++++++++++
> > >   .../devicetree/bindings/display/msm/qcom,dcp.yaml  | 123 +++++++++++++++++++
> > >   .../bindings/virtio/qcom,dcp-virtio.yaml           | 132 +++++++++++++++++++++
> > >   3 files changed, 334 insertions(+)
> > > 
> > My bot found errors running 'make dt_binding_check' on your patch:
> > 
> > yamllint warnings/errors:
> > 
> > dtschema/dtc warnings/errors:
> > /builds/robherring/linux-dt-review/Documentation/devicetree/bindings/virtio/qcom,dcp-virtio.yaml: iommu-ranges: multiple incompatible types: uint32-array
> > /usr/local/lib/python3.13/dist-packages/dtschema/schemas/iommu/iommu.yaml: iommu-ranges: multiple incompatible types: uint32-matrix
> > Could not decode node virtio@9be8000 property iommu-ranges with value b'\x00\x00\x00\x00\x84\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00'
> > 
> > Traceback (most recent call last):
> >    File "/usr/local/bin/dt-validate", line 8, in <module>
> >      sys.exit(main())
> >               ~~~~^^
> >    File "/usr/local/lib/python3.13/dist-packages/dtschema/dtb_validate.py", line 443, in main
> >      dtb_diagnostics = sg.check_dtb(filename)
> >    File "/usr/local/lib/python3.13/dist-packages/dtschema/dtb_validate.py", line 331, in check_dtb
> >      dt = self.validator.decode_dtb(f.read(), decode_errors)
> >    File "/usr/local/lib/python3.13/dist-packages/dtschema/validator.py", line 631, in decode_dtb
> >      return [dtschema.dtb.fdt_unflatten(self, dtb)]
> >              ~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
> >    File "/usr/local/lib/python3.13/dist-packages/dtschema/dtb.py", line 591, in fdt_unflatten
> >      dt = fdt_scan_node(validator, fdt, '/', offset)
> >    File "/usr/local/lib/python3.13/dist-packages/dtschema/dtb.py", line 320, in fdt_scan_node
> >      node = fdt_scan_node(validator, fdt, nodename, offset)
> >    File "/usr/local/lib/python3.13/dist-packages/dtschema/dtb.py", line 320, in fdt_scan_node
> >      node = fdt_scan_node(validator, fdt, nodename, offset)
> >    File "/usr/local/lib/python3.13/dist-packages/dtschema/dtb.py", line 312, in fdt_scan_node
> >      node_dict = node_props(validator, fdt, nodename, offset)
> >    File "/usr/local/lib/python3.13/dist-packages/dtschema/dtb.py", line 258, in node_props
> >      props_dict[p.name] = prop_value(validator, nodename, p)
> >                           ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
> >    File "/usr/local/lib/python3.13/dist-packages/dtschema/dtb.py", line 185, in prop_value
> >      if len(p) / type_format[fmt].size >= min_dim:
> >                  ~~~~~~~~~~~^^^^^
> > KeyError: 'uint32-array'
> > 
> > doc reference errors (make refcheckdocs):
> > 
> > See https://patchwork.kernel.org/project/devicetree/patch/20261026-jshekhar-dcp-hlos-v2-1-7cf014efdee1@oss.qualcomm.com
> > 
> > The base for the series is generally the latest rc1. A different dependency
> > should be noted in *this* patch.
> > 
> > If you already ran 'make dt_binding_check' and didn't see the above
> > error(s), then make sure 'yamllint' is installed and dt-schema is up to
> > date:
> > 
> > pip3 install dtschema --upgrade
> > 
> > Please check and re-submit after running the above command yourself. Note
> > that DT_SCHEMA_FILES can be set to your schema file to speed up checking
> > your schema. However, it must be unset to test all examples with your schema.
> 
> 
> There is a dependent patch which adds iommu-ranges, I had tried with that
> locally and it passes.

Where in the patch does it say that? The maintainer applying this series 
needs to know about the dependency, hence the report.

b4 provides for ways to define the base and any dependencies. Use that 
and then you won't get this report.

Rob