Re: [PATCH v5 1/4] dt-bindings: media: qcom,venus-common: Add IOMMU IOVA reservation region

[Vikash Garodia]

On 7/23/2026 2:36 PM, Konrad Dybcio wrote:
> On 7/23/26 12:03 AM, Bryan O'Donoghue wrote:
> > On 22/07/2026 14:41, Vikash Garodia wrote:
> > > Update the memory-region property to support two regions:
> > > 1. Firmware-loaded codec carveout (existing)
> > > 2. IOMMU IOVA reservation region (new)
> > >
> > > The IOMMU IOVA reservation region is required to restrict usage of
> > > specific IOVA memory range. For example, VPU restricts usage of 600MB
> > > for specific streams, which could otherwise lead to device crash. This
> > > change allows platforms to define separate memory regions for codec
> > > carveout and IOVA restrictions.
> > > This schema update supports existing DTS having single memory-region,
> > > thereby allowing gradual migration of DTS to support two memory region.
> > >
> > > Signed-off-by: Vikash Garodia<vikash.garodia@xxxxxxxxxxxxxxxx>
> > > ---
> >
> > I'm not mega-happy with this pattern being used - I prefer the pixel pixel_cb sub-node model you've proposed yourself.
> >
> > OTOH you're the maintainer so its really up to you how you want to arbitrate this - the 600MB constraint will work even if its not pretty or the best thing (tm).
> >
> > Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
>
> Doesn't this cause the same limitation that the initial patch
> by Daniel (all HW contexts can't access 0-600MiB anymore)?

Yes, it does, but for cases, like Shikra, which have single streams 
(with SMRs), there is no additional benefit in going with sub nodes in 
such case.

Regards,
Vikash

> Konrad