So I did some additional troubleshooting steps with kmdb and I have a beginning of an explanation.
The host bridges have vendor ID/product ID/header type values set to zero, so enumerate_bus_devs() skips over these devices and doesn't enumerate the rest of their device functions, notably the PCI bridges. The kernel then enumerates the peer busses, but their PCI configuration spaces return all ones because the PCI bridges aren't configured and therefore the kernel doesn't discover anything. The one exception is the SMBus device, which has valid vendor ID/device IDs and the header type has the multifunction bit set, so the kernel enumerates the rest of its functions, discovers the ISA bridge and eventually the serial port. If I binary patch at runtime enumerate_bus_devs() to not skip vendor IDs set to 0x0, the kernel does register device nodes for the host bridges, but without the multifunction bit set it still skips enumerating their functions. If I set up the PCI primary, secondary and subordinate bus numbers inside the PCI bridges by hand, the respective devices appear inside the PCI configuration space and the kernel creates device nodes for them, but doesn't attach drivers (probably because the bridges aren't fully configured). I assume that Linux does a complete enumeration of PCI busses, devices and functions and therefore doesn't miss the PCI bridges and the rest of the devices, despite the host bridges being apparently borked. I do not know why the host bridges themselves appear normal inside the output of lspci. That is as far as I'll investigate this on my own, because I draw the line at manually configuring memory ranges for PCI bridges through kmdb. I'm also not planning on setting up an illumos development environment to build kernels and mess with the PCI initialization code, as that exceeds my ragequit threshold. If someone wants to tackle this I'm willing to test things, otherwise I'm resigning to running Proxmox on that box. ------------------------------------------ illumos: illumos-discuss Permalink: https://illumos.topicbox.com/groups/discuss/Tb695f89d6fb11b82-Mb061661340364700f970d999 Delivery options: https://illumos.topicbox.com/groups/discuss/subscription
