acpi_ec_ecdt_probe => acpi_ec_identify

[Andriy Gapon]

on 05/02/2010 07:53 Nate Lawson said the following:
> Andriy Gapon wrote:
>> I would like to convert acpi_ec_ecdt_probe to device_identify method.
>> Rationale:
>> 1. It doesn't look like any device is using acpi_ec's services during identify
>> stage (or earlier) and acpi_ec already has a rather high priority among acpi
>> drivers that it would probe and attach before most of them.
>> 2. Making a driver 'less special' is always a good thing in general.
>> 3. Probing/attachment of acpi_ec at the current very early stage may even fail
>> because it could be dependent on things done by other, even more fundamental,
>> drivers that provide system resources.
>> 4. To expand the above: on some systems EC _REG method accesses things that only
>> get dynamically loaded after Processor's _PDC/_OSC is evaluated[*]. Converting
>> acpi_ec_ecdt_probe => acpi_ec_identify won't help here, but this would be a
>> first step towards a solution.
>>
>> [*]
>> http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/142561
>> Followups from Jan 15 on.
> 
> I agree in concept. The ECDT-based probe method was intended to get it
> active as early as possible, and Linux has a quirk to create a fake ECDT
> to get an early EC on some systems that require it but don't have an ECDT.
> 
> However, I thought jhb@'s multi-pass probe work would be a better way to
> support this than moving it into device_identify(). Is that code ready
> to use yet?

I agree with this.  But, unfortunately, the code doesn't seem to be as ready as
everyone would love it to be.


-- 
Andriy Gapon