Re: [PATCH RESEND v2] x86/early-quirks: Scan all functions in early_pci_scan_bus()

[Thorsten Blum <blum@kernel.org>]

Hi Bjorn,

On Mon, Oct 26, 2026 at 01:37:18PM -0500, Bjorn Helgaas wrote:
> On Wed, Sep 16, 2026 at 12:02:07PM +0200, Thorsten Blum wrote:
> > early_pci_scan_bus() stops scanning a PCI slot when check_dev_quirk()
> > returns nonzero, which avoids probing functions 1-7 on single-function
> > devices, but also stops scanning when a function is absent on a
> > multifunction device.
> > 
> > This can skip early quirks on multifunction devices with holes in their
> > function numbering.
> > 
> > On iMac13,1 and iMac13,2, the BCM4331 AirPort card is behind root port
> > 00:1c.3, also documented by the model list in commit abb2bafd295f
> > ("x86/quirks: Add early quirk to reset Apple AirPort card").
> > 
> > Public lspci output for 2012 iMacs [1][2] shows that 00:1c.0, 00:1c.2,
> > 00:1c.3 and 00:1c.4 are present, but 00:1c.1 is missing. The old code
> > stops at 00:1c.1 and never reaches 00:1c.3, so the AirPort reset quirk
> > is silently skipped on these machines.
> > 
> > Check function 0 first, and if it indicates a multifunction device, scan
> > functions 1-7 independently so that absent functions do not cause later
> > ones to be skipped.
> > 
> > Fixes: 15650a2f644a ("x86/PCI: fixup early quirk probing")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Thorsten Blum <blum@kernel.org>
> > Link: https://forum.libreelec.tv/thread/26799-wifi-not-detected-on-2012-imac-in-11-0/ [1]
> > Link: https://zoringroup.com/forum/5/7170/ [2]
> > Reviewed-by: Lukas Wunner <lukas@wunner.de>
> 
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> 
> Let me know if you'd prefer this to be merged via the PCI tree.

Thanks for the Ack.

I'd appreciate it if you could take this through the PCI tree.

Thanks,
Thorsten