On Tue, Dec 17, 2019 at 11:51:55PM +0800, Siddharth Kapoor wrote: > I would like to share a concern with the regulator patch which is part of > 4.9.196 LTS kernel. That's an *extremely* old kernel. > https://lore.kernel.org/lkml/20190904124250.25844-1-broonie@xxxxxxxxxx/ That's the patch "[PATCH] regulator: Defer init completion for a while after late_initcall" which defers disabling of idle regulators for a while. Please include human readable descriptions of things like commits and issues being discussed in e-mail in your mails, this makes them much easier for humans to read especially when they have no internet access. I do frequently catch up on my mail on flights or while otherwise travelling so this is even more pressing for me than just being about making things a bit easier to read. > We have reverted the patch in Pixel kernels and would like you to look into > this and consider reverting it upstream as well. I've got nothing to do with the stable kernels so there's nothing I can do here, sorry. However if this is triggering anything it's almost certainly some kind of timing issue (this code isn't new, it's just being run a bit later) and is only currently working through luck so I do strongly recommend trying to figure out the actual problem since it's liable to come back and bite you later - we did find one buggy driver in mainline as a result of this change, it's possible you've got another one. Possibly your GPU supplies need to be flagged as always on, possibly your GPU driver is forgetting to enable some supplies it needs, or possibly there's a missing always-on constraint on one of the regulators depending on how the driver expects this to work (if it's a proprietary driver it shouldn't be using the regulator API itself). I'm quite surprised you've not seen any issue before given that the supplies would still be being disabled earlier.
Attachment:
signature.asc
Description: PGP signature
