On Wed, 7 Jun 2023 at 04:59, Doug Anderson <dianders@xxxxxxxxxxxx> wrote: > > From a black box perspective, I guess the things I could think of > would be to keep poking around with things that you control. Best > ideas I have: > > 1. Use "bisect" style techniques to figure out how much you really > need to move the "lvs" regulators. Try moving it halfway up the list. > If that works, move it closer to the bottom. If that doesn't work, > move it closer to the top. Eventually you'd find out which regulator > it's important to be before. Hi, I tried this bisect style technique to move lvs regulators up in the list gradually and I found that they need to be enabled atleast before ldo12 and the ldo regulators which follow the ldo12 in the list. > > 2. Try adding some delays to some of the regulators with > "regulator-enable-ramp-delay" and/or "regulator-settling-time-us". > Without a scope, it'll be tricky to figure out exactly which > regulators might need delays, but you could at least confirm if the > "overkill" approach of having all the regulators have some delay > helps... I guess you could also try putting a big delay for "ldo26". > If that works, you could try moving it up (again using a bisect style > approach) to see where the delay matters? I tried this approach as well earlier today but I don't know how big "the big" delay can be. The device fails to boot if I add a settling time of as much as 2sec per each ldo and lvs regulator too. I didn't try increasing the delay further. Regards, Amit Pundir
