On 27/11/2024 19:49, Dmitry Baryshkov wrote: > On 27 November 2024 20:27:27 EET, Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote: >> On 27/11/2024 17:53, Dmitry Baryshkov wrote: >>> On Wed, Nov 27, 2024 at 08:23:04AM -0600, Rob Herring wrote: >>>> On Mon, Nov 25, 2024 at 05:45:10PM +0000, Raviteja Laggyshetty wrote: >>>>> EPSS instance on sc7280, sm8250 SoCs, use PERF_STATE register instead of >>>>> REG_L3_VOTE to scale L3 clocks, hence adding a new generic compatible >>>>> "qcom,epss-l3-perf" for these targets. >>>> >>>> Is this a h/w difference from prior blocks or you just want to use B >>>> instead of A while the h/w has both A and B? The latter sounds like >>>> driver policy. >>>> >>>> It is also an ABI break for s/w that didn't understand >>>> qcom,epss-l3-perf. >>> >>> As the bindings keep old compatible strings in addition to the new >>> qcom,epss-l3-perf, where is the ABI break? Old SW will use old entries, >>> newer can use either of those. >> No, this change drops qcom,epss-l3 and adds new fallback. How old >> software can work in such case? It's broken. > > Oh, I see. We had a platform-specific overrides for those two. Then I think we should completely drop the new qcom,epss-l3-perf idea and follow the sm8250 / sc7280 example. This means compatible = "qcom,sa8775p-perf", "qcom,epss-l3". It depends for example whether epss-l3 is valid at all. ABI is not broken if nothing was working in the first place, assuming it is explained in commit msg (not the case here). Best regards, Krzysztof
