From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Finn Thain <fthain@telegraphics.com.au>
Cc: Joshua Thompson <funaho@jurai.org>,
linux-m68k <linux-m68k@lists.linux-m68k.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] m68k/mac: Avoid stuck ISM IOP interrupt on Quadra 900/950
Date: Mon, 25 May 2020 10:46:10 +0200 [thread overview]
Message-ID: <CAMuHMdWSxz98B4HcBPbGj5e3TQx+ndUCLPeNg7ggdvpTzOA54A@mail.gmail.com> (raw)
In-Reply-To: <bfbb71db52c5e162d3afa25a28fc5d535ca87138.1589949122.git.fthain@telegraphics.com.au>
On Wed, May 20, 2020 at 6:41 AM Finn Thain <fthain@telegraphics.com.au> wrote:
> On a Quadra 900/950, the ISM IOP IRQ output pin is connected to an
> edge-triggered input on VIA2. It is theoretically possible that this
> signal could fail to produce the expected VIA2 interrupt.
>
> The two IOP interrupt flags can be asserted in any order but the logic
> in iop_ism_irq() does not allow for that. In particular, INT0 can be
> asserted right after INT0 is checked and before INT1 is cleared.
>
> Such an interrupt would produce no new edge and VIA2 would detect no
> further interrupts from the IOP. Avoid this by looping over the INT0/1
> handlers so an edge can be produced.
>
> Cc: Joshua Thompson <funaho@jurai.org>
> Tested-by: Stan Johnson <userm57@yahoo.com>
> Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
i.e. will queue in the m68k for-v5.8 branch.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
prev parent reply other threads:[~2020-05-25 8:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 4:32 [PATCH] m68k/mac: Avoid stuck ISM IOP interrupt on Quadra 900/950 Finn Thain
2020-05-25 8:46 ` Geert Uytterhoeven [this message]
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