Re: [PATCH v3 0/5] Introduce "non-pixel" sub node within iris video node

Krzysztof Kozlowski
2025-07-02T11:18:43Z

On 27/06/2025 17:48, Vikash Garodia wrote:
> This series introduces a sub node "non-pixel" within iris video node.
> Video driver registers this sub node as a platform device and configure
> it for DMA operations. All non pixel buffers, i.e bitstream, HFI queues
> and internal buffers related to bitstream processing, would be managed
> by this non_pixel device.
>
> Purpose to add this sub-node:
> Iris device limits the IOVA to an addressable range of 4GiB, and even
> within that range, some of the space is used by IO registers, thereby
> limiting the available IOVA to even lesser. For certain video usecase,
> this limited range in not sufficient enough, hence it brings the need to
> extend the possibility of higher IOVA range.
>
> Video hardware is designed to emit different stream-ID for pixel and
> non-pixel buffers, thereby introduce a non-pixel sub node to handle
> non-pixel stream-ID into a separate platform device.
> With this, both iris and non-pixel device can have IOVA range of
> approximately 0-4GiB individually for each device, thereby doubling the
> range of addressable IOVA.
>
> Tested on SM8550 and SA8775p hardwares.
>
> Signed-off-by: Vikash Garodia <quic_vgarodia@quicinc.com>
> ---
> Changes in v3:
> - Add info about change in iommus binding (Thanks Krzysztof)

Nothing improved in commit msg. You are changing existing device and the
reason for that change is not communicated at all.

There was big feedback from qualcomm saying that some commit in the past
received review, so future commits can repeat the same stuff. If qcom
approaches that way, sorry, no you need to come with proper commit
description.

Please align internally how to solve it, because my response that past
imperfect review is not justification for whatever future issues was not
enough.

Best regards,
Krzysztof