[RFC PATCH] irqchip/gic-v3: Claim iomem resources

[Robin Murphy]

On 2023-02-28 23:22, Marc Zyngier wrote:
> On Tue, 28 Feb 2023 23:11:15 +0000,
> Tim Harvey <tharvey at 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.

Indeed, according to [1], the GIC appears to overlap one of the "PCIe" 
windows of &ecam0, which conveniently appears to be the parent of the 
MMC controller as well.

Robin.

[1] 
https://github.com/Gateworks/dts-newport/blob/sdk-10.1.1.0-newport/cn81xx-linux.dtsi