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. >>> 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? Regards, Hans
