On 8/28/25 11:59 PM, Georgi Djakov wrote: > On 8/28/25 9:20 PM, Krzysztof Kozlowski wrote: >> On 28/08/2025 20:16, Odelu Kukatla wrote: >>> >>>>> QoS configuration is essential for managing latency and bandwidth across >>>>> subsystems such as CPU, GPU, and multimedia engines. Without it, the >>>>> system may experience performance degradation, especially under >>>> >>>> So how was it working for the last 2 years? >>>> >>> The system may function normally without this feature. However, enabling >> >> >> Huh? So you agree but keep continuing the discussion? >> >> I don't understand what we are discussing in such case, but just to >> close the topic from my side and be explicit: based on above you cannot >> break the ABI. > > To be even more specific, if we already have some DT binding without any > clocks and reg properties, we can't just suddenly change them from now > on to be "required". But they can still be "optional" and this will not > break the ABI, right? The old DT is still valid and the QoS will be > active when the new properties are present and this is handled properly > by the driver. Correct and this very approach was used to retrofit QoS onto an even older sc7280 icc driver. The icc-rpmh core already ignores QoS configuration if the clocks are not provided. Konrad
