2023-12-05 22:14:35

by Bjorn Andersson

Subject: [PATCH RFT] interconnect: qcom: icc-rpm: Fix peak rate calculation

Per the commit message of commit 'dd014803f260 ("interconnect: qcom:
icc-rpm: Add AB/IB calculations coefficients")', the peak rate should be
100/ib_percent. But, in what looks like a typical typo, the numerator
value is discarded in the calculation.

Update the implementation to match the described intention.

Fixes: dd014803f260 ("interconnect: qcom: icc-rpm: Add AB/IB calculations coefficients")
Cc: [email protected]
Signed-off-by: Bjorn Andersson <[email protected]>
---
Spotted while reading the code, patch is untested.
---
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 fb54e78f8fd7..a8ed435f696c 100644
--- a/drivers/interconnect/qcom/icc-rpm.c
+++ b/drivers/interconnect/qcom/icc-rpm.c
@@ -307,7 +307,7 @@ static u64 qcom_icc_calc_rate(struct qcom_icc_provider *qp, struct qcom_icc_node

if (qn->ib_coeff) {
agg_peak_rate = qn->max_peak[ctx] * 100;
- agg_peak_rate = div_u64(qn->max_peak[ctx], qn->ib_coeff);
+ agg_peak_rate = div_u64(agg_peak_rate, qn->ib_coeff);
} else {
agg_peak_rate = qn->max_peak[ctx];
}

---
base-commit: 0f5f12ac05f36f117e793656c3f560625e927f1b
change-id: 20231205-qcom_icc_calc_rate-typo-a1542df4f222

Best regards,
--
Bjorn Andersson <[email protected]>

2023-12-06 12:20:20

by Konrad Dybcio

Subject: Re: [PATCH RFT] interconnect: qcom: icc-rpm: Fix peak rate calculation

On 12/5/23 23:14, Bjorn Andersson wrote:
> Per the commit message of commit 'dd014803f260 ("interconnect: qcom:
> icc-rpm: Add AB/IB calculations coefficients")', the peak rate should be
> 100/ib_percent. But, in what looks like a typical typo, the numerator
> value is discarded in the calculation.
>
> Update the implementation to match the described intention.
>
> Fixes: dd014803f260 ("interconnect: qcom: icc-rpm: Add AB/IB calculations coefficients")
> Cc: [email protected]
> Signed-off-by: Bjorn Andersson <[email protected]>
> ---
> Spotted while reading the code, patch is untested.
> ---
> 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 fb54e78f8fd7..a8ed435f696c 100644
> --- a/drivers/interconnect/qcom/icc-rpm.c
> +++ b/drivers/interconnect/qcom/icc-rpm.c
> @@ -307,7 +307,7 @@ static u64 qcom_icc_calc_rate(struct qcom_icc_provider *qp, struct qcom_icc_node
>
> if (qn->ib_coeff) {
> agg_peak_rate = qn->max_peak[ctx] * 100;
> - agg_peak_rate = div_u64(qn->max_peak[ctx], qn->ib_coeff);
> + agg_peak_rate = div_u64(agg_peak_rate, qn->ib_coeff);
Oh fun.. I'dve assumed the compiler is smart enough to catch this

Reviewed-by: Konrad Dybcio <[email protected]>

Konrad