Re: [PATCH v2 6/6] media: qcom: camss: vfe: Add support for VFE 1080

Hangxiang Ma
2025-10-16T10:33:19Z

On 10/16/2025 6:09 PM, Bryan O'Donoghue wrote:
> On 15/10/2025 03:56, Hangxiang Ma wrote:
>> +
>> +        /* Deferring the reg update until after CSID config */
>> +        if (!vfe->camss->res->vfe_res[vfe->id].vfe.is_deferred)
>> +            ops->reg_update(vfe, line->id);
>>       }
>
> But why ?
>
> ---
> bod

That a story. When testing the RDI path on Kaanapali, we found one image
buffer starved at 19/20 stage. We want to capture 20 images but only 19
received.

On Kaanapali, the AUP and RUP are split into two separate registers not
a single one. Maybe this hardware change impacts something. Calling
ops->reg_update() in vfe_enable_output_v2 function only applies one
buffer address. The downstream code defers AUP and RUP to CSID
configuration stage. We mimic that and find it can solve this issue.

---
Hangxiang