On Fri, 18 Jan 2013, Myron Stowe wrote: > [+cc Shaohua and Kenji] > > On Fri, Jan 18, 2013 at 4:15 PM, Myron Stowe <myron.stowe@xxxxxxxxx> wrote: > > Joe: > > > > Thanks for the data. So the downstream port of interest has ASPM link > > capability but it's currently not enabled - see LnkCap and LnkCtl > > above. > > > > I'm still do not understand if PCI Express links would even be > > involved in a topology where all the devices connected below the > > downstream port are PCI and not PCI Express. Seems as if the ASPM > > code is going to a lot of work to put link state structures in place > > for all these devices that would not be capable of supporting ASPM. > > > > I'm still trying to come up to speed understanding ASPM so hopefully > > someone knowledgeable can help clue me in. > > > > Myron Scratch my earlier worry about link_state for a device without any subordinate devices for pcie_aspm_exit_link_state to clean up. I forgot the check that pcie_aspm_init_link_state makes on the subordinate device list before allocating link_state. What is confusing to me is the asymmetry between these two routines and how the pcie_aspm_sanity_check return value (blacklist, introduced in commit 46bbdfa4) is handled. I wonder if pcie_aspm_init_link_state could simply skip any device who's subordinate device list contains no pcie devices. (Actually one of the things that pcie_aspm_sanity_check looks for.) Regards, -- Joe -- 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
