Hi Srinivas, > On Feb 20, 2020, at 02:36, Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> wrote: > > Hi Kai, > > On Wed, 2020-02-19 at 22:22 +0800, Kai-Heng Feng wrote: >> Hi Srinivas, >> >> Your previous work to support DEVSLP works well on SATA SSDs, so I am >> asking you the issue I am facing: >> Once a laptop has a HDD installed, the power consumption during >> S2Idle increases ~0.4W, which is quite a lot. >> However, HDDs don't seem to support DEVSLP, so I wonder if you know >> to do proper power management for HDDs? > What is the default here > cat /sys/power/mem_sleep > s2idle or deep? It defaults to s2idle. > > Please follow debug steps here: > https://01.org/blogs/qwang59/2018/how-achieve-s0ix-states-linux > > We need to check whether you get any PC10 residency or not. Yes it reaches PC10. It doesn't reach SLP_S0 though. The real number on S2Idle power consumption: No HDD: ~1.4W One HDD: ~1.8W If the SoC doesn't hit PC10 the number should be significantly higher. That's why I think the issue is the power management on HDD itself. Kai-Heng > > Thanks, > Srinivas > > >> >> Kai-Heng >
