On 2014/9/26 0:46, Keith Busch wrote: > On Wed, 24 Sep 2014, Yijing Wang wrote: >> On 2014/9/25 7:30, Bjorn Helgaas wrote: >>> On Wed, Sep 24, 2014 at 4:41 PM, Keith Busch <keith.busch@xxxxxxxxx> wrote: >>>> Just poking this thread to make sure it's not dead. :) >>>> >>>> I tested Yijing's proposal and it is successful on our Intel server >>>> platforms; hoping either this or something that derives similar behavior >>>> will be applied so we can remove bus tuning kernel parameters. >>>> >>>> Tested-by: Keith Busch <keith.busch@xxxxxxxxx> >>> >>> Oops, thanks for poking me, because this was indeed dead. >>> >>> My main objection was to testing "is_hotplug_bridge". That doesn't >>> seem right, because this issue really isn't specific to hotplug. I >>> didn't see a resolution of that, but let me know if I missed it. >> >> Why I introduced "is_hotplug_bridge" is to avoid to touch the MPS which is not >> in hotplug case when pcie_bus_config == PCIE_BUS_TUNE_OFF. >> >> It's so sad that PCIe spec doesn't give a detailed guide to configure MPS. >> >> I'd like to refactor current MPS framework, but now there are still some puzzles >> to me. I need to have a deeper understanding of pcie mps. I read Jon's mps patch >> log from git, I found he turn off all this MPS config, because some issues were found >> in some platforms, but no platforms detailed info and no bugzilla records. > > Just my opinion, I thought the hotplug check was a good idea: it addresses > a known issue, and does not mess with current unknowns. Outside a hotplug > scenario, I think we expect platform f/w to handle MPS settings and the > kernel can stay out of the way because of the unknown platform issues. If > it is hotplug, having the kernel set device's MPS to match the parent > couldn't make things worse off than doing nothing, right? Yes, I think so, but it all decided by Bjorn. I think he want a better solution, and current patch just still is a temporary fix. > > On the side, I'll see if I can ping some comrades on PCI-SIG to propose > an ECN to clarify configuring MPS. They usually ignore me though, so no > promises. :) Thanks in advance for your help :) > > . > -- Thanks! Yijing -- 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
