Linux PCI subsystem development
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From: Lukas Wunner <lukas@wunner.de>
To: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Jesse Barnes <jbarnes@hobbes.lan>, Ingo Molnar <mingo@elte.hu>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/early-quirks: Scan all functions in early_pci_scan_bus()
Date: Sun, 16 Aug 2026 07:25:22 +0200	[thread overview]
Message-ID: <aoFJwldO-_qttr0P@wunner.de> (raw)
In-Reply-To: <20260807094601.263450-2-thorsten.blum@linux.dev>

On Fri, Aug 07, 2026 at 11:46:02AM +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.
> 
> 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.

Which device do you need this for?  We should only scan additional
Functions if a quirk needs to applied to them because this extends
boot time.  It requires a justification and shouldn't be done "just
because".

Thanks,

Lukas

  parent reply	other threads:[~2026-08-16  5:25 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-07  9:46 [PATCH] x86/early-quirks: Scan all functions in early_pci_scan_bus() Thorsten Blum
2026-08-07  9:51 ` sashiko-bot
2026-08-16  5:25 ` Lukas Wunner [this message]
2026-08-16 20:48   ` Thorsten Blum

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