Re: [RFC PATCH] interconnect: qcom: icc-rpm: Don't call __qcom_icc_set twice on the same node

[Bryan O'Donoghue]

On 03/03/2023 11:35, Bryan O'Donoghue wrote:
> On 03/03/2023 11:33, Konrad Dybcio wrote:
> > 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@xxxxxxxxxx>
> > > > ---
> > > > 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)
>
> So you've _seen_ that happen ?

Assuming you have, then why isn't the fix in sync_state i.e. that's an 
error for everybody right ?