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Date:   Mon, 5 Jul 2021 12:54:51 +0200 (CEST)
From:   "Maciej W. Rozycki" <macro@orcam.me.uk>
To:     Nikolai Zhubr <zhubr.2@gmail.com>
cc:     Bjorn Helgaas <bhelgaas@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, Arnd Bergmann <arnd@kernel.org>,
        x86@kernel.org, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC 0/2] x86/PCI: SiS PIRQ router updates
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On Sat, 3 Jul 2021, Maciej W. Rozycki wrote:

> > >   Nikolai, can you please give it a hit with the extra debug patch as
> > > requested in my other message?
> > 
> > With
> > linux-x86-pirq-router-sis85c503.diff applied
> > linux-x86-pirq-router-sis85c497.diff applied
> > and DEBUG 1 in arch/x86/include/asm/pci_x86.h
> > here is new log:
> > 
> > https://pastebin.com/n3udQgcq
> > 
> > My feeling is that something went a bit wrong because:
> > 
> > 8139too 0000:00:0d.0: can't route interrupt
> 
>  More important is actually the previous line:
> 
> PCI: Attempting to find IRQ router for [0000:0000]
> 
> meaning that the PIRQ structure defined by the BIOS has not specified the 
> vendor:device ID pair for the router [1039:0496] which we match against.

 So it's actually both the vendor:device ID pair and the bus address that 
matter here.  I've now posted a patch I am fairly sure about that combined 
with the earlier changes it will fix your issue.  I have verified it in a 
simulated environment where the PIRQ routing table has an invalid vendor 
ID given, with correct results produced:

PCI: Attempting to find IRQ router for [0000:0000]
PCI: Trying IRQ router for [8086:1250]
PCI: Trying IRQ router for [8086:7000]
pci 0000:00:07.0: SIO/PIIX/ICH IRQ router [8086:7000]

 Please let me know of the outcome.

  Maciej