Re: [PATCH] slimbus: qcom-ngd-ctrl: match downstream DEF_ACT_CHAN encoding
From: Srinivas Kandagatla
Date: Thu Sep 17 2026 - 21:06:03 EST
On 8/18/26 1:50 PM, Konrad Dybcio wrote:
> On 8/8/26 2:35 AM, Casey Tunturi via B4 Relay wrote:
>> From: Casey Tunturi <casey@xxxxxxxxxxxxxxxxxxxxxx>
>>
>> During my investigations, and some rather incessant cross-checking of
>> blueline's SLIMbus path, I found that Qualcomm's downstream driver
>> packs the first DEF_ACT_CHAN byte differently from mainline. Bits [7:5]
>> hold the data format; bits [4:0] hold the five-bit client number.
>>
>> I changed ours to match. It made no immediate difference on my own
>> hardware: blueline's current values produce 0x0f either way. The
>> downstream layout is correct and should help devices that use upper
>> logical-address bits or a non-zero data format.
>>
>> Fixes: 52490169cddf ("slimbus: ngd: add stream support")
>> Cc: stable@xxxxxxxxxxxxxxx
there is no regression
We already set this in(stream.c) define_channel_content for each port
after enabling the channel.
--srini
>> Signed-off-by: Casey Tunturi <casey@xxxxxxxxxxxxxxxxxxxxxx>
>> ---
>
> The semantics match, I don't know what side effects that may uncover>
> Acked-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
>
> Konrad