On Wednesday, September 08, 2010 11:21 AM, Jesse Barnes wrote: > On Fri, 3 Sep 2010 11:59:30 -0700 > "Allan, Bruce W" <bruce.w.allan@xxxxxxxxx> wrote: > >> ASPM L1 must be disabled on this device otherwise the latency >> described above will happen. And even though there are log messages >> indicating ASPM L1 is disabled, it really isn't according to the >> verbose lspci output and PCI config space for the 2:0.0 device (see >> LnkCtl above). Since CONFIG_PCIEASPM is enabled in your kernel >> config, the driver is calling the kernel function >> pci_disable_link_state() to disable ASPM L1 which it fails to do >> because the variable aspm_disabled=1 (as indicated by the "ACPI FADT >> declares the system doesn't support PCIe ASPM, so disable it" >> message). >> >> I'm unclear on whether the aspm_disabled variable is meant to >> indicate ASPM L0s or both ASPM L0s _and_ L1 are disabled (added PCI >> maintainer and linux-pci mail-list). To resolve this issue, we need >> to either a) change e1000e to directly write the PCI config space to >> disable ASPM L1 as was done before 6f461f6c7c, or b) fix >> pci_disable_link_state() et. al. to allow for ASPM L1 to be disabled >> properly. I would prefer the latter option so that other drivers do >> not have to use the same kludge to write to the PCI config space. >> Any input from the PCI guys? > > Yeah, I'd prefer this code to be in the core. Are there any patches > available yet? Nothing from me at this point (been on vacation). I might be able to look into this further but not for another week or so (need to catch up on the backlog that piled up while away). Bruce. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
