[+cc Yinghai] On Mon, Aug 03, 2015 at 01:33:20PM -0700, Barry Grussling wrote: > > Can you attach complete dmesg logs and "lspci -vv" output for both > > cases? (You can attach them to a kernel.org bugzilla if they're too > > big for email.) > > > > Can do: > https://bugzilla.kernel.org/show_bug.cgi?id=102231 > > > The dmesg logs will tell us what space is allocated to the host > > bridge. That is generally done by firmware or the bootloader, and > > Linux doesn't change it. So if firmware only assigns 0xc0000000 to > > 0xc59fffff to the host bridge, the current Linux kernel will only > > assign PCI devices inside that region; it will never expand the > > region. > Okay. That makes sense. > > We are using u-boot. I don't believe our current u-boot build has any > PCIe knowledge in it though. You might have a host bridge driver that knows how to set up the windows. Your dmesg logs mention altera_hps2fpga_bridge, which doesn't seem to be in the upstream kernel, so I don't know what it does. Both logs show this: PCI host bridge to bus 0000:00 pci_bus 0000:00: root bus resource [mem 0xc0000000-0xcfffffff] pci_bus 0000:00: root bus resource [mem 0xd0000000-0xdfffffff pref] which means the top-level apertures are the same regardless of whether 08:00.0 is present at boot. That means the PCI core should be able to assign space for the hot-added device, at least in principle. The log where 08:00.0 is present at boot shows this: pci 0000:08:00.0: [1aa9:0013] type 00 class 0x020000 pci 0000:08:00.0: reg 0x10: [mem 0x00000000-0x000fffff] (size 1M) pci 0000:08:00.0: reg 0x14: [mem 0x00000000-0x00ffffff] (size 16M) pci 0000:08:00.0: reg 0x18: [mem 0x00000000-0x00ffffff] (size 16M) pci 0000:08:00.0: reg 0x1c: [mem 0x00000000-0x000003ff] (size 1K) pci 0000:08:00.0: reg 0x20: [mem 0x00000000-0x000003ff] (size 1K) pci 0000:08:00.0: reg 0x24: [mem 0x00000000-0x000003ff] (size 1K) so it needs a little over 33M of space. In the other log ("08:00.0 not present at boot"), we actually *do* enumerate an 08:00.0 device: pci 0000:08:00.0: [1d00:0000] type 00 class 0x00001d pci 0000:08:00.0: reg 0x30: [mem 0x00001800-0x00001fff pref] I don't know what this device is (lspci says "non-VGA unclassified device") and it only requests 2K of space for an option ROM. And the log doesn't include the part where you hot-add the real device -- that's the interesting information should be. I see that you already boot with "pcie=hpmemsize=256M", but that doesn't help in this case because it's only used for hotplug bridges, and 02:0f.0 (the Downstream Port leading to bus 08) is not marked as hotplug-capable: 02:0f.0 PCI bridge: PLX Technology, Inc. PEX 8619 Capabilities: [68] Express (v2) Downstream Port (Slot+), MSI 00 SltCap: AttnBtn- PwrCtrl- MRL- AttnInd- PwrInd- HotPlug- Surprise- I think if you could get the PCI_EXP_SLTCAP_HPC bit set for 02:0f.0, and you booted with "pcie=hpmemsize=256M", it would likely work. It's possible it could be made to work even without that, but in general it's hard to reserve the right amount of space for a bridge if you don't know what might be plugged in later. 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
