On Wed, Nov 11, 2020 at 04:03:30PM +0000, Limonciello, Mario wrote: > > >> Given we're effectively ending up with the combination of runtime PM turned > > >> on by udev rules, do we need something like this for that ID: > > >> > > >> > > https://github.com/torvalds/linux/commit/6a7c533d4a1854f54901a065d8c672e890400 > > d8a > > >> > > >> @Mika Westerberg should 8086:a0ed be quirked like the TCSS xHCI too? > > > > > > I think this one is the TGL PCH xHCI. The quirk currently for xHCI > > > controllers that are part of the TCSS (Type-C SubSystem) where it is > > > important to put all devices into low power mode whenever possible, > > > otherwise it keeps the whole block on. > > > > Note that there are currently some IDs missing from the xHCIs which > > are part of the TCSS too. At least the id for the xHCI in the thunderbolt > > controller on the Lenovo T14 gen 1 is missing. I started a discussion > > about extending the kernel quirk list for this vs switching to hwdb > > a while a go: > > > > https://lore.kernel.org/linux-usb/b8b21ba3-0a8a-ff54-5e12- > > cf8960651086@xxxxxxxxxx/ > > > > The conclusion back then was to switch to hwdb, but I never got around to > > this. > > I guess the problem I see with switching to a hwdb for this type of thing is > that if there is a "bug" in your kernel driver around autosuspend you will > then be potentially causing it to occur more regularly on a kernel that didn't > necessarily pick up the fix but does have the newer hwdb. > > I don't know how common that will really be though. > > Since Mika mentioned the really light userspace scenario, what about shipping > the hwdb "with" the kernel in tree? This could allow evicting all these quirk > scenarios from the kernel at the same time as switching to a hwdb and also cover > the problem I suggested might happen with a bug in older kernel and newer userspace. We took things out of the kernel to put it in hwdb years ago as it was easier for people to update a "text file" than it was their kernel image. I don't think you want to go backwards here :) thanks, greg k-h
