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

From: Bryan O'Donoghue
Date: Mon Aug 28 2023 - 11:43:57 EST


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