Message-ID: <29513b9e-8561-7f7e-370e-7515116c7ee6@linaro.org>
Date:   Fri, 3 Mar 2023 12:33:15 +0100
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Subject: Re: [RFC PATCH] interconnect: qcom: icc-rpm: Don't call
 __qcom_icc_set twice on the same node
Content-Language: en-US
To:     Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
        linux-arm-msm@vger.kernel.org, andersson@kernel.org,
        agross@kernel.org
Cc:     marijn.suijten@somainline.org, Georgi Djakov <djakov@kernel.org>,
        linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230303023500.2173137-1-konrad.dybcio@linaro.org>
 <59b28fb4-1367-9872-ed63-90847e380bb6@linaro.org>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <59b28fb4-1367-9872-ed63-90847e380bb6@linaro.org>
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On 3.03.2023 12:32, Bryan O'Donoghue wrote:
> On 03/03/2023 02:35, Konrad Dybcio wrote:
>> Currently, when sync_state calls set(n, n) all the paths for setting
>> parameters on an icc node are called twice. Avoid that.
>>
>> Fixes: 751f4d14cdb4 ("interconnect: icc-rpm: Set destination bandwidth as well as source bandwidth")
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
>> ---
>> RFC comes from the fact that I *believe* this should be correct, but I'm
>> not entirely sure about it..
>>
>>
>>   drivers/interconnect/qcom/icc-rpm.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/interconnect/qcom/icc-rpm.c b/drivers/interconnect/qcom/icc-rpm.c
>> index a6e0de03f46b..d35db1af9b08 100644
>> --- a/drivers/interconnect/qcom/icc-rpm.c
>> +++ b/drivers/interconnect/qcom/icc-rpm.c
>> @@ -387,7 +387,7 @@ static int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
>>       ret = __qcom_icc_set(src, src_qn, sum_bw);
>>       if (ret)
>>           return ret;
>> -    if (dst_qn) {
>> +    if (dst_qn && src_qn != dst_qn) {
>>           ret = __qcom_icc_set(dst, dst_qn, sum_bw);
>>           if (ret)
>>               return ret;
> 
> Is it possible for src_qn == dst_qn ?
As the commit message says, sync_state calls set(n, n) in
drivers/interconnect/core.c : icc_sync_state(struct device *dev)

Konrad
> 
> Iff you confirm that experimentally - add my
> 
> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>