Re: [ACPI] acpi_bus_register_driver() returns -ENODEV after resume

[Karol Kozimor <sziwan-DETuoxkZsSqrDJvtcaxF/A@public.gmane.org>]

Thus wrote Patrick Mochel:
> Since it's __initdata, the memory will be freed early in the init process 
> (c.f. init/main.c::init() -> free_initmem()). Anything that uses it later 
> is touching memory that is either unallocated, or allocated by something 
> else. That's a bug. 
> 
> Also, it doesn't need to be EXPORTed. If it is left as initdata, that's
> another bug, because the two are semantically disjoint. However, even with
> the patch below, I'm not sure why you would want to expose the variable 
> (and I've in fact removed that). 

Sounds reasonable, but... what about modular ACPI? At least 
acpi_bus_register_driver() uses acpi_disabled, so it would seem to me that
every time we're loading an ACPI driver module, acpi_disabled evaluates to 
something random, as in the aforementioned case?

Additionally, if acpi_disabled is to be available for modules (i.e. modular
ACPI), it should rather be exported, shouldn't it?

> Tangential question: Do preprocessor conditionals evaluate to a value? 
> I.e. instead of doing: 
> 
> #ifdef	CONFIG_ACPI
> 	int acpi_disabled = 0;
> #else
> 	int acpi_disabled = 1;
> #endif
> 
> Could we do: 
> 
> int acpi_disabled = (CONFIG_ACPI == 'y'); 

AFAIK acpi_disabled is independent on CONFIG_ACPI, i.e. CONFIG_ACPI may be
defined, but if acpi=off is passed to the kernel command line,
acpi_disabled evaluates to 1?
Best regards and a 1:20 am CEST disclaimer: I might be talking nonsenses.

-- 
Karol 'sziwan' Kozimor
sziwan-DETuoxkZsSqrDJvtcaxF/A@public.gmane.org


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