MIME-Version: 1.0
References: <20230306044737.862-1-honda@mechatrax.com> <6e1fe1015235ae7d7eb9ef2526fd64b6d6d628d7.camel@gmail.com>
In-Reply-To: <6e1fe1015235ae7d7eb9ef2526fd64b6d6d628d7.camel@gmail.com>
From:   Masahiro Honda <honda@mechatrax.com>
Date:   Tue, 7 Mar 2023 19:54:20 +0900
Message-ID: <CA+Tz-SHQxNzx=eS8ex=3Hps0th5bTY+K1qSWrZqWC8ryv+d0RA@mail.gmail.com>
Subject: Re: [PATCH] Fix IRQ issue by setting IRQ_DISABLE_UNLAZY flag
To:     =?UTF-8?B?TnVubyBTw6E=?= <noname.nuno@gmail.com>
Cc:     Lars-Peter Clausen <lars@metafoo.de>,
        Michael Hennerich <Michael.Hennerich@analog.com>,
        Jonathan Cameron <jic23@kernel.org>, linux-iio@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Mon, Mar 6, 2023 at 10:30=E2=80=AFPM Nuno S=C3=A1 <noname.nuno@gmail.com=
> wrote:
>
> Hmmm this looks to be a very likely issue for any device having to
> brute force IRQ disabling by disabling the line (disable_irq()). That
> said, I think the commit message can (needs) to be improved. The
> message feels a bit confusing to me. Also, having a reference to
>
> commit e9849777d0e2 ("genirq: Add flag to force mask in
> disable_irq[_nosync]()")
>
> would be nice to give some background on why this can be an issue.
>
> Another thing that came to my mind is if the data is totally
> garbage/wrong or is it just some outstanding sample?
>
>
> Some research on this also seems to point that we should (need?) call
> irq_clear_status_flags(irq, IRQ_DISABLE_UNLAZY) when freeing the IRQ.
>

Thank you for your reply. I'll improve it.

> I also wonder if we should keep this out of the library and have a per
> device config? Sure, this won't make anything wrong but it will hurt
> performance. OTOH, even though no one else ever reported this before,
> it looks like this can be an issue for all of the supported sigma delta
> ADCs.
>

I'll also investigate it.