On Wed, 6 Mar 2024 at 10:39, Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> wrote: > > On Wed, Mar 06, 2024 at 08:20:16AM +0100, Johan Hovold wrote: > > On Wed, Mar 06, 2024 at 12:03:02PM +0530, Manivannan Sadhasivam wrote: > > > 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. > > > > > > 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. > > > > Ok, thanks for confirming. But then the devicetree property is not the > > right way to handle this, and we should disable L0s based on the > > compatible string instead. > > > > Hmm. I checked further and got the info that there is no change in the IP, but > the PHY sequence is not tuned correctly for L0s (as I suspected earlier). So > there will be AERs when L0s is enabled on any controller instance. And there > will be no updated PHY sequence in the future also for this chipset. Why? If it is a bug in the PHY driver, it should be fixed there instead of adding workarounds. > > So yeah, let's disable it in the driver instead. > > > > > 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). > > > > I'll respin the series. Looks like we've already missed the chance to > > enable ITS in 6.9 anyway. > > > > Sounds good, thanks! > > - Mani > > -- > மணிவண்ணன் சதாசிவம் > -- With best wishes Dmitry
