Date:   Tue, 28 Feb 2023 23:22:57 +0000
Message-ID: <86lekhl6i6.wl-maz@kernel.org>
From:   Marc Zyngier <maz@kernel.org>
To:     Tim Harvey <tharvey@gateworks.com>
Cc:     Robin Murphy <robin.murphy@arm.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Al Cooper <alcooperx@gmail.com>,
        Adrian Hunter <adrian.hunter@intel.com>, tglx@linutronix.de,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] irqchip/gic-v3: Claim iomem resources
In-Reply-To: <CAJ+vNU3+rz50MRQQsz39Jfbspy2ig9tqzb_yg1RFooxGutCM+g@mail.gmail.com>
References: <c534c2a458a3bf94ccdae8abc6edc3d45a689c30.1649777295.git.robin.murphy@arm.com>
        <CAJ+vNU3+rz50MRQQsz39Jfbspy2ig9tqzb_yg1RFooxGutCM+g@mail.gmail.com>
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On Tue, 28 Feb 2023 23:11:15 +0000,
Tim Harvey <tharvey@gateworks.com> wrote:
> 
> I have bisected a kernel issue where octeontx (CN803x) will hang on
> reboot caused by commit c0db06fd0993 ("mmc: core: Disable card detect
> during shutdown"). This commit made it into 5.16 and stable kernels.
> I've found that the patch here which is commit 2b2cd74a06c3 resolves
> this hang but I'm not entirely clear why.
> 
> Does anyone have a good explanation of why the hang occurs in the
> first place and why this resolves it? I would like to get the proper
> fix into the affected stable branches.

Wild guess: the reservation prevents some other driver from probing
because the firmware describes overlapping ranges, and that driver is
what is causing your above hang.

But you don't give much information that would allow this theory to be
checked. I guess you'll have to instrument your kernel and find out.

	M.

-- 
Without deviation from the norm, progress is not possible.