On Tue, Feb 27, 2024 at 04:29:15PM +0100, Johan Hovold wrote: > On Fri, Feb 23, 2024 at 04:10:00PM -0600, Bjorn Helgaas wrote: > > On Fri, Feb 23, 2024 at 04:21:16PM +0100, Johan Hovold wrote: > > > Commit 9f4f3dfad8cf ("PCI: qcom: Enable ASPM for platforms supporting > > > 1.9.0 ops") started enabling ASPM unconditionally when the hardware > > > claims to support it. This triggers Correctable Errors for some PCIe > > > devices on machines like the Lenovo ThinkPad X13s, which could indicate > > > an incomplete driver ASPM implementation or that the hardware does in > > > fact not support L0s. > > > > Are there any more details about this? Do the errors occur around > > suspend/resume, a power state transition, or some other event? Might > > other DWC-based devices be susceptible? Is there a specific driver > > you suspect might be incomplete? > > I see these errors when the devices in question are active as well as > idle (not during suspend/resume). For example, when running iperf3 or > fio to test the wifi and nvme, but I also see this occasionally for a > wifi device which is (supposedly) not active (e.g. a handful errors over > night). > > I skimmed Qualcomm's driver and noted that there are some registers > related to ASPM which that driver updates, while the mainline driver > leaves them at their default settings, but I essentially only mentioned > that the ASPM implementation may be incomplete as a theoretical > possibility. The somewhat erratic ASPM behaviour for one of the modems > also suggests that some further tweak/quirk may be needed, and I was > hoping to catch Mani's interest by reporting it. > > But based on what I've since heard from Qualcomm, it seems like these > correctable error may be a known issue with the hardware (e.g. seen > also with Windows), which is also why we decided to disable it for all > controllers on these two platforms where I've seen this in v2. > > > Do you want the DT approach because the problem is believed to be > > platform-specific? Otherwise, maybe we should consider reverting > > 9f4f3dfad8cf until the problem is understood? > > Enabling ASPM gave a very significant improvement in battery life on the > Lenovo ThinkPad X13s, from 10.5 h to 15 h, so reverting is not really an > option there. Ah, I missed that you're only disabling L0s, but leaving L1 enabled, thanks! And given that the v1.9.0 ops that enable ASPM are used on a bunch of platforms, and L0s seems to work fine on most of them, we wouldn't want to disable L0s for everybody, so this seems like the right solution. Bjorn