On Tue, Mar 05, 2024 at 09:10:55AM +0100, Johan Hovold wrote: > This series addresses a few problems with the sc8280xp PCIe > implementation. > > The DWC PCIe controller can either use its internal MSI controller or an > external one such as the GICv3 ITS. Enabling the latter allows for > assigning affinity to individual interrupts, but results in a large > amount of Correctable Errors being logged on both the Lenovo ThinkPad > X13s and the sc8280xp-crd reference design. > > It turns out that these errors are always generated, but for some yet to > be determined reason, the AER interrupts are never received when using > the internal MSI controller, which makes the link errors harder to > notice. > > On the X13s, there is a large number of errors generated when bringing > up the link on boot. This is related to the fact that UEFI firmware has > already enabled the Wi-Fi PCIe link at Gen2 speed and restarting the > link at Gen3 generates a massive amount of errors until the Wi-Fi > firmware is restarted. This has now also been shown to cause the Wi-Fi > to sometimes not start at all on boot for some users. > > A recent commit enabling ASPM on certain Qualcomm platforms introduced > further errors when using the Wi-Fi on the X13s as well as when > accessing the NVMe on the CRD. The exact reason for this has not yet > been identified, but disabling ASPM L0s makes the errors go away. This > could suggest that either the current ASPM implementation is incomplete > or that L0s is not supported with these devices. > > Note that the X13s and CRD use the same Wi-Fi controller, but the errors > are only generated on the X13s. The NVMe controller on my X13s does not > support L0s so there are no issues there, unlike on the CRD which uses a > different controller. The modem on the CRD does not generate any errors, > but both the NVMe and modem keeps bouncing in and out of L0s/L1 also > when not used, which could indicate that there are bigger problems with > the ASPM implementation. I don't have a modem on my X13s so I have not > been able to test whether L0s causes any trouble there. > > Enabling AER error reporting on sc8280xp could similarly also reveal > existing problems with the related sa8295p and sa8540p platforms as they > share the base dtsi. > > After discussing this with Bjorn Andersson at Qualcomm we have decided > to go ahead and disable L0s for all controllers on the CRD and the > X13s. > Just received confirmation from Qcom that L0s is not supported for any of the PCIe instances in sc8280xp (and its derivatives). Please move the property to SoC dtsi. - Mani > Note that disabling ASPM L0s for the X13s Wi-Fi does not seem to have a > significant impact on the power consumption (and there are indications > that this applies generally for L0s on these platforms). > > *** > > As we are now at 6.8-rc7, I've rebased this series on the Qualcomm PCIe > binding rework in linux-next so that the whole series can be merged for > 6.9 (the 'aspm-no-l0s' support and devicetree fixes are all marked for > stable backport anyway). > > The DT bindings and PCI patch are expected to go through the PCI tree, > while Bjorn A takes the devicetree updates through the Qualcomm tree. > > Johan > > > Changes in v3 > - drop the two wifi link speed patches which have been picked up for > 6.8 > - rebase on binding rework in linux-next and add the properties also to > the new qcom,pcie-common.yaml > - https://lore.kernel.org/linux-pci/20240126-dt-bindings-pci-qcom-split-v3-0-f23cda4d74c0@xxxxxxxxxx/ > - fix an 'L0s' typo in one commit message > > Changes in v2 > - drop RFC from ASPM patches and add stable tags > - reorder patches and move ITS patch last > - fix s/GB/MB/ typo in Gen2 speed commit messages > - fix an incorrect Fixes tag > - amend commit message X13 wifi link speed patch after user > confirmation that this fixes the wifi startup issue > - disable L0s also for modem and wifi on CRD > - disable L0s also for nvme and modem on X13s > > > Johan Hovold (10): > dt-bindings: PCI: qcom: Allow 'required-opps' > dt-bindings: PCI: qcom: Do not require 'msi-map-mask' > dt-bindings: PCI: qcom: Allow 'aspm-no-l0s' > PCI: qcom: Add support for disabling ASPM L0s in devicetree > arm64: dts: qcom: sc8280xp: add missing PCIe minimum OPP > arm64: dts: qcom: sc8280xp-crd: disable ASPM L0s for NVMe > arm64: dts: qcom: sc8280xp-crd: disable ASPM L0s for modem and Wi-Fi > arm64: dts: qcom: sc8280xp-x13s: disable ASPM L0s for Wi-Fi > arm64: dts: qcom: sc8280xp-x13s: disable ASPM L0s for NVMe and modem > arm64: dts: qcom: sc8280xp: enable GICv3 ITS for PCIe > > .../bindings/pci/qcom,pcie-common.yaml | 6 +++++- > .../devicetree/bindings/pci/qcom,pcie.yaml | 6 +++++- > arch/arm64/boot/dts/qcom/sc8280xp-crd.dts | 5 +++++ > .../qcom/sc8280xp-lenovo-thinkpad-x13s.dts | 5 +++++ > arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 17 +++++++++++++++- > drivers/pci/controller/dwc/pcie-qcom.c | 20 +++++++++++++++++++ > 6 files changed, 56 insertions(+), 3 deletions(-) > > -- > 2.43.0 > -- மணிவண்ணன் சதாசிவம்
