Re: [PATCH v2 7/7] PCI/quirks: Avoid certain address on Genoa systems

[Ilpo Järvinen]

On Sun, 4 Oct 2026, Borislav Petkov wrote:

> On Fri, Oct 02, 2026 at 02:33:15PM +0300, Ilpo Järvinen wrote:
> > While testing the resource placement changes, tests hit a case where
> > igb fails to probe when BAR 0 is placed at 0x9c000000:
> > 
> >    90000000-9cffffff : PCI Bus 0000:a0
> >   -  90000000-902fffff : PCI Bus 0000:a1
> >   -    90000000-900fffff : 0000:a1:00.0
> >   -      90000000-900fffff : igb
> >   -    90100000-901fffff : 0000:a1:00.0
> >   -    90200000-90203fff : 0000:a1:00.0
> >   -      90200000-90203fff : igb
> >   +  9be00000-9c0fffff : PCI Bus 0000:a1
> >   +    9be00000-9befffff : 0000:a1:00.0
> >   +    9bf00000-9bf03fff : 0000:a1:00.0
> >   +    9c000000-9c0fffff : 0000:a1:00.0
> >      9c100000-9c17ffff : amd_iommu
> >      9c180000-9c1803ff : IOAPIC 8
> > 
> >   -       Region 0: Memory at 90000000 (32-bit, non-prefetchable) [size=1M]
> >   -       Region 3: Memory at 90200000 (32-bit, non-prefetchable) [size=16K]
> >   -       Expansion ROM at 90100000 [disabled] [size=1M]
> >   +       Region 0: Memory at 9c000000 (32-bit, non-prefetchable) [size=1M]
> >   +       Region 3: Memory at 9bf00000 (32-bit, non-prefetchable) [size=16K]
> >   +       Expansion ROM at 9be00000 [disabled] [size=1M]
> > 
> > igb 0000:a1:00.0 0000:a1:00.0 (uninitialized): PCIe link lost
> > ------------[ cut here ]------------
> > igb: Failed to read reg 0x18!
> > WARNING: drivers/net/ethernet/intel/igb/igb_main.c:724 at igb_rd32.cold+0x3c/0x4f [igb], CPU#32: kworker/32:1/706
> > ...
> >  igb_get_invariants_82575+0xff/0xf00 [igb]
> >  igb_probe+0x3c8/0x1190 [igb]
> >  local_pci_probe+0x3b/0x80
> > 
> > It turns out there is a 64kB iomem black hole at 9c000000 that returns
> 
> Can we please debug that "It turns out" thing and try to find out what really
> is going on here.
> 
> Can you pls explain what your machine looks like so that we can try to
> reproduce it and see what's going on?

It's Poweredge R6625. AFAIK, there's nothing fancy on it, just the I210 
added. (I don't admin it but can just run large-scale validation tests on 
it so I could have gaps in my knowledge).

> Does it have latest BIOS, microcode, etc etc? If it doesn't, can you upgrade
> and try again?

BIOS was updated to the latest and the problem persists.

> I guess dmesg, hwinfo, kernel .config would be good starters, privately is
> fine too.

dmesg is in the ticket, I added config there.

-- 
 i.