From: Milton Miller <miltonm@bga•com>
To: Olof Johansson <olof@lixom•net>
Cc: paulus@samba•org, linuxppc-dev@ozlabs•org
Subject: Re: [PATCH v2] powerpc: Add workaround for MPICs with broken register reads
Date: Fri, 7 Sep 2007 09:11:52 -0500 [thread overview]
Message-ID: <326829233f0e99b0e0404241f5faaa7a@bga.com> (raw)
In-Reply-To: <20070907092143.GB32102@lixom.net>
On Sep 7, 2007, at 4:21 AM, Olof Johansson wrote:
> Some versions of PWRficient 1682M have an interrupt controller in which
> the first register in each pair for interrupt sources doesn't always
> read with the right polarity/sense values.
>
> To work around this, keep a software copy of the register instead.
> Since
> it's not modified from the mpic itself, it's a feasible solution.
> Still,
> keep it under a config option to avoid wasting memory on other
> platforms.
>
> Signed-off-by: Olof Johansson <olof@lixom•net>
>
>
> diff --git a/arch/powerpc/platforms/Kconfig
> b/arch/powerpc/platforms/Kconfig
> index 041df77..f2e7049 100644
> --- a/arch/powerpc/platforms/Kconfig
> +++ b/arch/powerpc/platforms/Kconfig
> @@ -137,6 +137,18 @@ config MPIC_U3_HT_IRQS
> depends on PPC_MAPLE
> default y
>
> +config MPIC_BROKEN_REGREAD
> + bool "MPIC workaround for broken register reads"
> + depends on MPIC
> + help
> + Say Y here to enable a MPIC driver workaround for some chips that
> + have a bug that causes some interrupt source information to not
> + read back properly. It is safe to use on other chips as well, but
> + enabling it uses about 8KB of memory to keep copies of the register
> + contents in software.
> +
> + Say N if you are unsure.
> +
>
I'm sorry, I didn't mean to imply it should be asked / selectable, just
that the help should be provided. I won't object to leaving it except
that it asks the average user unnecessary questions. In other words,
drop the question after bool.
milton
next prev parent reply other threads:[~2007-09-07 14:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-05 2:44 [PATCH] powerpc: Add workaround for MPICs with broken register reads Olof Johansson
2007-09-06 14:55 ` Milton Miller
2007-09-07 9:16 ` Olof Johansson
2007-09-07 9:21 ` [PATCH v2] " Olof Johansson
2007-09-07 14:11 ` Milton Miller [this message]
2007-09-07 19:12 ` Olof Johansson
2007-09-07 19:13 ` [PATCH v3] " Olof Johansson
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