Hi MyungJoo, On 2019-01-28 09:05, MyungJoo Ham wrote: >> This way devfreq core ensures that all its devices will be set to safe >> operation points before reboot operation. There are board on which some >> aggressive power saving operation points are behind the capabilities of >> the bootloader to properly reset the hardware and boot the board. This >> way one can avoid board crash early after reboot. >> >> Similar pattern is used in CPUfreq subsystem. >> >> Reported-by: Markus Reichl <m.reichl@xxxxxxxxxxxxx> >> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> >> --- > You are invoking ALL devfreq suspend callbacks at shutdown > with this commit. > > Can you make it invoke only devices explicitly saying their needs > to handle "SHUTDOWN" event? > > For example, we can add a flag at struct devfreq_dev_profile: > "uint32_t requirement" > , where > 0x1: need to operate at the initial frequency for suspend > 0x2: need to operate at the initial frequency for shutdown > 0x4: it forgets its status at resume, reconfigure frequency at resume. > (or reverse 0x1's semantics for the backward compatibility) Frankly speaking this looks like an over-engineering. Switching to safe frequency during reboot shouldn't have any negative side-effects. IMHO such flags can be always added later, once there will be a real use case for them. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
