Re: [PATCH 3/4] arm64: dts: qcom: msm8996: Improve GPU OPP table

[Dmitry Baryshkov]

On Fri, 26 May 2023 at 16:30, Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> wrote:
>
>
>
> On 30.03.2023 12:57, Konrad Dybcio wrote:
> >
> >
> > On 29.03.2023 23:32, Dmitry Baryshkov wrote:
> >> On Wed, 29 Mar 2023 at 22:17, Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> wrote:
> >>>
> >>> Remove the self-explanatory comment about opp-supported-hw contents,
> >>> add required-opps to ensure reasonable power domain levels are voted
> >>> for (currently we've been piggybacking off of miracles and MDP votes)
> >>> and add newlines between each subnode.
> >>
> >> I'm not sure this is 100% correct. The values that you add are correct
> >> for the voltage scaling case. However, based on the vendor kernel
> >> sources I think that MX should only be scaled if the voltage is scaled
> >> too. I might be wrong here.
> > MX must be >= CX (and GX), so this should bring no harm.
> >
> > (citation needed, but that seems to hold true..)
> With that in mind, would you ack these patches Dmitry?

I remember that we should not overwolt the memory, it might cause
memory cells degradation. So MX >= CX & MX <= CX + delta.

I have pinged Jordan if he can provide feedback on my a530/540 voltage
programming attempt ([1]), but got no response from him up to now.

[1] https://git.linaro.org/people/dmitry.baryshkov/kernel.git/log/?h=msm8996-upstream

I will try doing more experiments with the mentioned branch. Maybe it
breaks because of the missing MX vote or because of something
suchalike.
I'm 80% sure in the voltage level (which were generated by the CPR3 on
my db820c board) and 95% sure in the programming sequence.

>
> Konrad
> >
> > Konrad
> >>
> >>>
> >>> Fixes: 69cc3114ab0f ("arm64: dts: Add Adreno GPU definitions")
> >>> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
> >>> ---
> >>>  arch/arm64/boot/dts/qcom/msm8996.dtsi | 18 +++++++++++++-----
> >>>  1 file changed, 13 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/arch/arm64/boot/dts/qcom/msm8996.dtsi b/arch/arm64/boot/dts/qcom/msm8996.dtsi
> >>> index 4dd37f72e018..62ad30e94f40 100644
> >>> --- a/arch/arm64/boot/dts/qcom/msm8996.dtsi
> >>> +++ b/arch/arm64/boot/dts/qcom/msm8996.dtsi
> >>> @@ -1244,37 +1244,45 @@ gpu: gpu@b00000 {
> >>>                         gpu_opp_table: opp-table {
> >>>                                 compatible = "operating-points-v2";
> >>>
> >>> -                               /*
> >>> -                                * 624Mhz is only available on speed bins 0 and 3.
> >>> -                                * 560Mhz is only available on speed bins 0, 2 and 3.
> >>> -                                * All the rest are available on all bins of the hardware.
> >>> -                                */
> >>>                                 opp-624000000 {
> >>>                                         opp-hz = /bits/ 64 <624000000>;
> >>> +                                       required-opps = <&rpmpd_opp_turbo>;
> >>>                                         opp-supported-hw = <0x09>;
> >>>                                 };
> >>> +
> >>>                                 opp-560000000 {
> >>>                                         opp-hz = /bits/ 64 <560000000>;
> >>> +                                       required-opps = <&rpmpd_opp_turbo>;
> >>>                                         opp-supported-hw = <0x0d>;
> >>>                                 };
> >>> +
> >>>                                 opp-510000000 {
> >>>                                         opp-hz = /bits/ 64 <510000000>;
> >>> +                                       required-opps = <&rpmpd_opp_nom>;
> >>>                                         opp-supported-hw = <0xff>;
> >>>                                 };
> >>> +
> >>>                                 opp-401800000 {
> >>>                                         opp-hz = /bits/ 64 <401800000>;
> >>> +                                       required-opps = <&rpmpd_opp_nom>;
> >>>                                         opp-supported-hw = <0xff>;
> >>>                                 };
> >>> +
> >>>                                 opp-315000000 {
> >>>                                         opp-hz = /bits/ 64 <315000000>;
> >>> +                                       required-opps = <&rpmpd_opp_svs>;
> >>>                                         opp-supported-hw = <0xff>;
> >>>                                 };
> >>> +
> >>>                                 opp-214000000 {
> >>>                                         opp-hz = /bits/ 64 <214000000>;
> >>> +                                       required-opps = <&rpmpd_opp_svs>;
> >>>                                         opp-supported-hw = <0xff>;
> >>>                                 };
> >>> +
> >>>                                 opp-133000000 {
> >>>                                         opp-hz = /bits/ 64 <133000000>;
> >>> +                                       required-opps = <&rpmpd_opp_svs>;
> >>>                                         opp-supported-hw = <0xff>;
> >>>                                 };
> >>>                         };
> >>>
> >>> --
> >>> 2.40.0
> >>>
> >>
> >>



-- 
With best wishes
Dmitry