Re: [PATCH v3 15/15] media: qcom: camss: Comment CSID dt_id field

Bryan O'Donoghue
2023-08-28T15:43:55Z

On 28/08/2023 16:38, Konrad Dybcio wrote:
> On 28.08.2023 17:34, Bryan O'Donoghue wrote:
>> On 26/08/2023 11:18, Konrad Dybcio wrote:
>>>> +        /*
>>>> +         * A value caled 'CID' gets generated internal to CAMSS logic
>>>> +         * which is a concatenation of [vc:6 | dt_id:2] hence we reuse
>>>> +         * the least significant two bits of the VC to 'stuff' the CID value.
>>>> +         */
>>>>           u8 dt_id = vc;
>>> And where are you discarding the non-2-lsb?
>>
>> At the assignment of dt_id
>>
>> vc:6
>> dt_id:2
>>
>> =>
>>
>> cid:8 = [vc:6 | dt_id:2]
>> vc == 00110110
>> cid = [110110 | 10]
>>
>> I have no more information what CID is or how the bitfield is populated than I have already indicated in the comment/commit log.
>>
> OK so you're discarding the 2 lsb of the [vc:6|dt_id:2]
>
> however
>
> the way I read the comment would suggest that you're taking
> vc[6:2]
>
> Konrad

Fair enough, obvs the comment needs work so.

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bod