Hi Geert, > -----Original Message----- > From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > Subject: [PATCH/RFC 0/2] arm64: dts: renesas: Re-add voltages to OPP tables > > Hi all, > > When CONFIG_ENERGY_MODEL=y, an error is printed on RZ/G2E and R-Car E3: > > cpu cpu0: EM: invalid perf. state: -22 > > This happens because the Operating Points Parameters tables do not list voltages, as they are all > identical. Previously, it was assumed they were optional, and unused, when none of the CPU nodes is > tied to a regulator using the "cpu-supply" property. This assumption turned out to be incorrect, > causing the reported error message. > > This RFC patch series fixes this by adding the missing voltages. > > Note that the Energy Model calculates energy efficiency by dividing the > (estimated) CPU power consumption by CPU core clock frequency. When all voltages have the same value, > the former is proportional to clock frequency, and energy efficiency becomes a constant. Hence all > operating points are considered to have the same efficiency, and the Energy Model always picks the one > with the highest clock rate (see also [1]). > > Alternatively, the Energy Model could be changed to silently ignore OPP tables with missing > frequencies. IMHO this is not an unusual case. I guess cooling uses OPP table for frequency down scaling at higher temp. So, we need OPP tables for thermal governors?? Cheers, Biju > > Which approach should be taken? > Thanks for your comments! > > [1] "PM: EM: Question Potential Issue with EM and OPP Table in cpufreq > ondemand Governor" > https://lore.kernel.org/all/a2ca883e-122e-43a1-b377-c43956b5b3be@xxxxxxx > > Geert Uytterhoeven (2): > arm64: dts: renesas: r8a774c0: Re-add voltages to OPP table > arm64: dts: renesas: r8a77990: Re-add voltages to OPP table > > arch/arm64/boot/dts/renesas/r8a774c0.dtsi | 3 +++ arch/arm64/boot/dts/renesas/r8a77990.dtsi | 3 +++ > 2 files changed, 6 insertions(+) > > -- > 2.34.1 > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx > > In personal conversations with technical people, I call myself a hacker. But when I'm talking to > journalists I just say "programmer" or something like that. > -- Linus Torvalds
