Hi Heiner, On Fri, Feb 22, 2019 at 12:16 AM Heiner Kallweit <hkallweit1@xxxxxxxxx> wrote: > > I face the issue that a PCIe network chip misses RX packets if ASPM L1 > sub-states are enabled. It seems that the RX FIFO is too small to buffer > all incoming packets during ASPM exit latency. > > So far pci_disable_link_state() only allows to disable L1 completely. > Would it make sense to extend this function to allow disabling > L1 sub-states selectively? Looking at pcie_config_aspm_link() this > seems to be possible. We could certainly explore the option of selectively disabling L1 substates. But before we do that, let's look at a couple things, because there are some Linux issues in that area, and it's possible we could make a generic fix that wouldn't require disabling the substates completely. One problem is the ASPM L1.2 state depends on LTR information, and we don't support LTR correctly. There are a couple patches in -next to fix some problems, but we still don't handle cases where the BIOS doesn't program the LTR latencies and the LTR_L1.2_Threshold. Can you open a report at bugzilla.kernel.org and attach the complete dmesg log (booted with "pci=earlydump") and the "sudo lspci -vvvxx" output? Have you figured out which L1 substate specifically causes problems? If not, maybe we can use setpci to fiddle with things manually and narrow it down. Bjorn
