On Mon, Feb 12, 2024 at 05:50:33PM +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, How did you confirm this? > 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. > If you manually inject the errors using "aer-inject", are you not seeing the AER errors with internal MSI controller as well? > 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. > > 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. > What are those "further errors" you are seeing with ASPM enabled? Are those errors appear with GIC ITS or with internal MSI controller as well? > 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 an 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. > > The last four patches, marked as RFC, adds support for disabling ASPM > L0s in the devicetree and disables it selectively for the X13s Wi-Fi > and CRD NVMe. If it turns out that the Qualcomm PCIe implementation is > incomplete, we may need to disable ASPM (L0s) completely in the driver > instead. > If the device is not supporting L0s, then it as to be disabled in the device, not in the PCIe controller, no? > Note that disabling ASPM L0s for the X13s Wi-Fi does not seem to have a > significant impact on the power consumption > > 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. > Since I took a stab at enabling the GIC ITS previously, I noticed that the NVMe performance got a slight dip. And that was one of the reasons (apart from AER errors) that I never submitted the patch. Could you share the NVMe benchmark (fio) with this series? > Johan > > > Johan Hovold (10): > dt-bindings: PCI: qcom: Allow 'required-opps' > dt-bindings: PCI: qcom: Do not require 'msi-map-mask' > arm64: dts: qcom: sc8280xp: add missing PCIe minimum OPP > arm64: dts: qcom: sc8280xp-crd: limit pcie4 link speed > arm64: dts: qcom: sc8280xp-x13s: limit pcie4 link speed > arm64: dts: qcom: sc8280xp: enable GICv3 ITS for PCIe Is this patch based on the version I shared with you long back? If so, I'd expect to have some credit. If you came up with your own version, then ignore this comment. - Mani > dt-bindings: PCI: qcom: Allow 'aspm-no-l0s' > PCI: qcom: Add support for disabling ASPM L0s in devicetree > arm64: dts: qcom: sc8280xp-crd: disable ASPM L0s for NVMe > arm64: dts: qcom: sc8280xp-x13s: disable ASPM L0s for Wi-Fi > > .../devicetree/bindings/pci/qcom,pcie.yaml | 6 +++++- > arch/arm64/boot/dts/qcom/sc8280xp-crd.dts | 4 ++++ > .../qcom/sc8280xp-lenovo-thinkpad-x13s.dts | 3 +++ > arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 17 +++++++++++++++- > drivers/pci/controller/dwc/pcie-qcom.c | 20 +++++++++++++++++++ > 5 files changed, 48 insertions(+), 2 deletions(-) > > -- > 2.43.0 > -- மணிவண்ணன் சதாசிவம்
