Re: [PATCH v3 01/11] dt-bindings: reserved-memory: Document Tegra VPR

[Rob Herring]

On Thu, Jul 2, 2026 at 7:58 AM Thierry Reding <thierry.reding@xxxxxxxxxx> wrote:
>
> On Wed, Jul 01, 2026 at 02:53:10PM -0500, Rob Herring (Arm) wrote:
> >
> > On Wed, 01 Jul 2026 18:08:12 +0200, Thierry Reding wrote:
> > > From: Thierry Reding <treding@xxxxxxxxxx>
> > >
> > > The Video Protection Region (VPR) found on NVIDIA Tegra chips is a
> > > region of memory that is protected from CPU accesses. It is used to
> > > decode and play back DRM protected content.
> > >
> > > It is a standard reserved memory region that can exist in two forms:
> > > static VPR where the base address and size are fixed (uses the "reg"
> > > property to describe the memory) and a resizable VPR where only the
> > > size is known upfront and the OS can allocate it wherever it can be
> > > accomodated.
> > >
> > > Reviewed-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
> > > Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> > > ---
> > > Changes in v2:
> > > - add examples for fixed and resizable VPR
> > > ---
> > >  .../nvidia,tegra-video-protection-region.yaml      | 76 ++++++++++++++++++++++
> > >  1 file changed, 76 insertions(+)
> > >
> >
> > My bot found errors running 'make dt_binding_check' on your patch:
> >
> > yamllint warnings/errors:
> >
> > dtschema/dtc warnings/errors:
> > /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/reserved-memory/nvidia,tegra-video-protection-region.example.dtb: protected@2a8000000 (nvidia,tegra-video-protection-region): reg: [[2, 2818572288], [0, 1879048192]] is too long
> >       from schema $id: http://devicetree.org/schemas/reserved-memory/nvidia,tegra-video-protection-region.yaml
> > /builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/reserved-memory/nvidia,tegra-video-protection-region.example.dtb: protected@2a8000000 (nvidia,tegra-video-protection-region): Unevaluated properties are not allowed ('no-map', 'reg' were unexpected)
> >       from schema $id: http://devicetree.org/schemas/reserved-memory/nvidia,tegra-video-protection-region.yaml
>
> Any ideas why that second error shows up? It turns out that it goes away
> when the first one is fixed (which admittedly is a stupid mistake), but
> I spent quite a bit of time looking for a fix before realizing that it's
> only a side-effect of the first.

If a property fails validation in a referenced schema, then everything
in that referenced schema is considered not evaluated. So then
unevaluatedProperties is applied to the properties only in the
referenced schema. That's why 'no-map' is also unevaluated. Just a
quirk of how json-schema works...

Rob