linux-kernel - Re: [tip:x86/urgent] x86/quirks: Add early quirk to reset Apple AirPort card

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Date:	Fri, 10 Jun 2016 13:58:45 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Lukas Wunner <lukas@...ner.de>,
	Thomas Gleixner <tglx@...utronix.de>, cmilsted@...hat.com,
	Rafa?? Mi??ecki <zajec5@...il.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Matt Fleming <matt@...eblueprint.co.uk>,
	Peter Zijlstra <peterz@...radead.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Matthew Garrett <mjg59@...f.ucam.org>, m@...s.ch,
	"linux-tip-commits@...r.kernel.org" 
	<linux-tip-commits@...r.kernel.org>
Subject: Re: [tip:x86/urgent] x86/quirks: Add early quirk to reset Apple
 AirPort card


* Yinghai Lu <yinghai@...nel.org> wrote:

> On 6/9/16, Lukas Wunner <lukas@...ner.de> wrote:
> >
> > Well, the PCI core would also scan such a bus twice AFAICS.
> > And the performance penalty of scanning it twice seems negligible.
> > Early quirks can prevent double execution by setting QFLAG_APPLY_ONCE.
> > (Three quirks have set that flag already.)
> >
> > So I think this shouldn't be a concern.
> 
> I don't know. I would like see sth like following, and that is simple enough.
> 
> Index: linux-2.6/arch/x86/kernel/early-quirks.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/early-quirks.c
> +++ linux-2.6/arch/x86/kernel/early-quirks.c
> @@ -755,10 +755,16 @@ static int __init check_dev_quirk(int nu
>         return 0;
>  }
> 
> +static unsigned char __initdata scanned[256];
>  static void __init early_pci_scan_bus(int bus)
>  {
>         int slot, func;
> 
> +       if (scanned[bus])
> +               return;
> +
> +       scanned[bus] = 1;
> +
>         /* Poor man's PCI discovery */
>         for (slot = 0; slot < 32; slot++)
>                 for (func = 0; func < 8; func++) {

Ok, I removed the fix from tip:x86/urgent from the time being - could you guys 
please send a full version once a final approach is agreed upon?

Thanks,

	Ingo