Re: [PATCH] PCI: rcar-host: Add static assertion to check !PCI_LOCKLESS_CONFIG

[Marek Vasut <marek.vasut@mailbox.org>]

On 9/22/25 5:48 PM, Marek Vasut wrote:

Hello Geert,

>>> +/*
>>> + * This driver can not function correctly without PCIe subsystem level
>>> + * config space access serialization. In case PCI_LOCKLESS_CONFIG is
>>> + * ever enabled on ARM, complain loudly so the driver can be updated
>>> + * accordingly.
>>> + */
>>> +static_assert(!IS_ENABLED(CONFIG_PCI_LOCKLESS_CONFIG));
>>> +
>>>   struct rcar_msi {
>>>          DECLARE_BITMAP(used, INT_PCI_MSI_NR);
>>>          struct irq_domain *domain;
>>
>> This causes a build failure when compile-testing, e.g. x86 allmodconfig.
>> Using "depends on !PCI_LOCKLESS_CONFIG" instead would avoid that,
>> but indeed has the disadvantage that it wouldn't complain loudly when
>> PCI_LOCKLESS_CONFIG would ever be enabled on ARM64...
> All right, let's also wait for input from PCI maintainers. It seems both 
> alternatives -- static_assert() and !PCI_LOCKLESS_CONFIG have their own 
> disadvantages, maybe there is a third option.

Maybe we can try with both.

-- 
Best regards,
Marek Vasut