On 18. Feb 2023, at 00:46, Saravana Kannan <saravanak@xxxxxxxxxx> wrote: > > On Fri, Feb 17, 2023 at 3:33 PM Christian Kohlschütter > <christian@xxxxxxxxxxxxxxxx> wrote: >> >> On 18. Feb 2023, at 00:22, Saravana Kannan <saravanak@xxxxxxxxxx> wrote: >>> >>> On Thu, Aug 25, 2022 at 2:28 PM Christian Kohlschütter >>> <christian@xxxxxxxxxxxxxxxx> wrote: >>>> >>>> Previously, an unresolved regulator supply reference upon calling >>>> regulator_register on an always-on or boot-on regulator caused >>>> set_machine_constraints to be called twice. >>>> >>>> This in turn may initialize the regulator twice, leading to voltage >>>> glitches that are timing-dependent. A simple, unrelated configuration >>>> change may be enough to hide this problem, only to be surfaced by >>>> chance. >>> >>> In your case, can you elaborate which part of the constraints/init >>> twice caused the issue? >>> >>> I'm trying to simplify some of the supply resolving code and I'm >>> trying to not break your use case. >>> >>> -Saravana >> >> Here's a write-up of my use case, and how we got to the solution: >> https://kohlschuetter.github.io/blog/posts/2022/10/28/linux-nanopi-r4s/ > > I did read the write up before I sent my request. I'm asking for > specifics on which functions in the set_machine_constraints() was > causing the issue. And it's also a bit unclear to me if the issue was > with having stuff called twice on the alway-on regulator or the > supply. > > -Saravana I'm afraid I cannot give a more detailed answer than what's in the write up and the previous discussion on this mailing list; I thought it's pretty detailed already. However, it should be relatively straightforward to reproduce the issue.
