acpi_ec_ecdt_probe => acpi_ec_identify
nate at root.org
Fri Feb 5 05:53:41 UTC 2010
Andriy Gapon wrote:
> I would like to convert acpi_ec_ecdt_probe to device_identify method.
> 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.
> 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?
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