Hi, On 11/24/20 1:37 PM, Mathias Nyman wrote: > On 23.11.2020 15.54, Hans de Goede wrote: >> Hi, >> >> On 11/11/20 3:31 PM, Mika Westerberg wrote: >>> On Wed, Nov 11, 2020 at 12:27:32PM +0100, Hans de Goede wrote: >>>> Hi, >>>> >>>> On 11/10/20 6:25 PM, Mika Westerberg wrote: >>>>> On Tue, Nov 10, 2020 at 04:02:33PM +0000, Limonciello, Mario wrote: >>>>>>> >>>>>>> On Tue, Nov 10, 2020 at 11:57:07AM +0100, Bastien Nocera wrote: >>>>>>>> Hey, >>>>>>>> >>>>>>>> systemd has been shipping this script to enable auto-suspend on a >>>>>>>> number of USB and PCI devices: >>>>>>>> >>>>>>> https://github.com/systemd/systemd/blob/master/tools/chromiumos/gen_autosuspen >>>>>>> d_rules.py >>>>>>>> >>>>>>>> The problem here is twofold. First, the list of devices is updated from >>>>>>>> ChromeOS, and the original list obviously won't be updated by ChromeOS >>>>>>>> developers unless a device listed exists in a ChromeBook computer, >>>>>>>> which means a number of devices that do support autosuspend aren't >>>>>>>> listed. >>>>>>>> >>>>>>>> The other problem is that this list needs to exist at all, and that it >>>>>>>> doesn't seem possible for device driver developers (at various levels >>>>>>>> of the stack) to opt-in to auto-suspend when all the variants of the >>>>>>>> device (or at least detectable ones) support auto-suspend. >>>>>>> >>>>>>> A driver can say they support autosuspend today, but I think you are >>>>>>> concerned about the devices that are controlled by class-compliant >>>>>>> drivers, right? And for those, no, we can't do this in the kernel as >>>>>>> there are just too many broken devices out there. >>>>>>> >>>>>> >>>>>> I guess what Bastien is getting at is for newer devices supported by class >>>>>> drivers rather than having to store an allowlist in udev rules, can we set >>>>>> the allowlist in the kernel instead. Then distributions that either don't >>>>>> use systemd or don't regularly update udev rules from systemd can take >>>>>> advantage of better defaults on modern hardware. >>>>>> >>>>>> The one item that stood out to me in that rules file was 8086:a0ed. >>>>>> It's listed as "Volteer XHCI", but that same device ID is actually present >>>>>> in an XPS 9310 in front of me as well and used by the xhci-pci kernel module. >>>>>> >>>>>> 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/6a7c533d4a1854f54901a065d8c672e890400d8a >>>>>> >>>>>> @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. >>> >>> The reason I've added these to the xHCI driver is that it works even if >>> you are running some really small userspace (like busybox). Also for the >>> xHCI in TCSS we know for sure that it fully supports D3cold. >>> >>> (The one you refer above is actually mistake from my side as I never >>> tested Alpine Ridge LP controller which I think this is). >> >> Ok, so I'll submit a patch adding the 15c1 product-id for the >> INTEL_ALPINE_RIDGE_LP_2C_XHCI controller to the list of ids for which we >> set the XHCI_DEFAULT_PM_RUNTIME_ALLOW quirk. To fix the much too high >> idle-power consumption problem on devices with this Alpine Ridge variant. > > Thanks > >> >>>>> Typically we haven't done that for PCH side xHCI controllers though, but >>>>> I don't see why not if it works that is. Adding Mathias to comment more >>>>> on that since he is the xHCI maintainer. >>>> >>>> If we are also going to enable this for the non TCSS Intel XHCI controllers, >>>> maybe just uncondtionally enable it for all Intel XHCI controllers, or >>>> if necessary do a deny-list for some older models and enable it for anything >>>> not on the deny-list (so all newer models). That should avoid the game of >>>> whack-a-mole which we will have with this otherwise. >>> >>> This is really up to Mathias to decide. I'm fine either way :) >> >> Ok, Matthias what do you think about this? > > I don't think we are ready to enable runtime pm as default for all Intel xHCI controllers. > The risk of xHCI not waking up when user plugs a mouse/keyboard, making the system unusable > just seems too high compared to the powersaving benefit. > > The powersaving benefit from autosuspending the TCSS xHCI is a lot better, and we, (Mika mostly) > has been able to verify they work. > > So I propose we for now continue adding TCSS xHCI controllers to the allowlist in kernel. > For others I think a userspace allow/denylist makes sense. > > Long term goal would be default allow for all, with short denylist in kernel. Ok, thank you for your input on this. Regards, Hans
