On 2012/9/20 9:47, Yijing Wang wrote: >>> We compared the two situations after BIOS initialization, and found Max Payload Size in DEVCTRL is 256B >>> if FC card had been installed, if the slot is empty, Max Payload Size is 128B. We force it to be 128B when >>> FC card installed when system boot up. Finally pci hotplug becomes ok. So I suspect maybe our PCIe hardware >>> has problem supporting 256B. >> >> Ah, this sounds like something I've been worried about for a while, >> i.e., do we handle MPS correctly when we hot-add devices? >> >> Yijing, I'm not quite clear on what you're observing. I guess you're >> saying that if an FC card is installed at boot, the BIOS sets MPS to >> 256, and that if no FC card is installed, the BIOS sets MPS to 128? > > Yes. > >> You haven't mentioned any Linux boot options, so I assume you haven't >> tried any. Does "pci=pcie_bus_safe" make any difference? > > Yes, I don't add any Linux boot options before. I will try this boot option > "pci=pcie_bus_safe". > >> Jon, here's a pointer to the beginning of the thread: >> http://marc.info/?l=linux-pci&m=134770460302298&w=2 (full dmesg log at >> http://marc.info/?l=linux-scsi&m=134788365823217&w=2). I'm not sure >> we have enough in the dmesg log to diagnose an issue like this. I >> wonder if it would be useful to log the current setting, so we could >> notice BIOS default differences like this one. >> Hi Bjorn, After add "pci=pcie_bus_safe" boot options, Hot-plug for FC card is OK. It's great! Thanks for your help! Giri, it's not the fc card problem, we fix this problem by add boot option "pci=pcie_bus_safe" which force the MPS of the entire system to the smallest possible. Thanks Yijing >> Bjorn >> -- >> 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 >> >> . >> > > -- Thanks! Yijing -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
