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Message-ID: <582e4c0b-5cd3-7fac-cba7-7250a458a60d@arm.com>
Date:   Thu, 16 Jun 2022 13:19:08 +0100
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Subject: Re: [PATCH] arm64: dts: ti: k3-j721s2: fix overlapping GICD memory
 region
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To:     Marc Zyngier <maz@kernel.org>
Cc:     Matt Ranostay <mranostay@ti.com>, Nishanth Menon <nm@ti.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20220616105112.289719-1-mranostay@ti.com>
 <9b005c7d-e434-c215-288d-3926f483b07a@arm.com> <87y1xw3iy9.wl-maz@kernel.org>
From:   Robin Murphy <robin.murphy@arm.com>
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On 2022-06-16 13:13, Marc Zyngier wrote:
> On Thu, 16 Jun 2022 13:07:23 +0100,
> Robin Murphy <robin.murphy@arm.com> wrote:
>>
>> On 2022-06-16 11:51, Matt Ranostay wrote:
>>> GICD region was overlapping with GICR causing the latter to not map
>>> successfully, and in turn the gic-v3 driver would fail to initialize.
>>>
>>> This issue was hidden till commit 2b2cd74a06c3 ("irqchip/gic-v3: Claim iomem resources")
>>> replaced of_iomap() calls with of_io_request_and_map() that internally
>>> called request_mem_region().
>>>
>>> Respective console output before this patchset:
>>>
>>> [    0.000000] GICv3: /bus@100000/interrupt-controller@1800000: couldn't map region 0
>>
>> Oh, it's nice that this finds bugs, but it seems I hadn't fully
>> considered that making the simple easy change in the DT paths results
>> in different behaviour from ACPI.
>>
>> Marc, would you like a fix for this to remain non-fatal even in the
>> face of a dodgy DT, or are you happy with being a bit stricter now?
> 
> I'd rather we work around it. I shout at people for breaking existing
> DTs, so this should apply to the GIC as well. A nice WARN_ON_ONCE()
> should do, if you don't mind writing the patch.

Indeed, I think that would be my default preference as well - apologies 
for the oversight! I'll spin the patch shortly (and make the warning 
consistent for the ACPI side too).

Cheers,
Robin.