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Date:   Tue, 3 May 2022 20:46:45 +0100 (BST)
From:   "Maciej W. Rozycki" <macro@orcam.me.uk>
To:     Geert Uytterhoeven <geert@linux-m68k.org>
cc:     Rob Landley <rob@landley.net>,
        John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
        Sergey Shtylyov <s.shtylyov@omp.ru>,
        Rich Felker <dalias@libc.org>,
        Linux-sh list <linux-sh@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v3] sh: avoid using IRQ0 on SH3/4
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On Tue, 3 May 2022, Geert Uytterhoeven wrote:

> > Sounds like it's now outside of the IRQ range allocation, but I can't find where
> > that's requested when registering the controller? (What is a "swizzle" anyway?)
> 
> PCI slots have 4 interrupts (#A, #B, #C, #D). In machines with
> multiple slots, the interrupts lines are "swizzled", to avoid that all cards
> using a single interrupt are mapped to the same host interrupt.

 Especially as single-function devices are required to use INTA.

  Maciej