Re: [PATCH 0/4] Convert ACPI fan driver to platform driver

[Aaron Lu <aaron.lu@intel.com>]

On Thu, Dec 05, 2013 at 12:07:31AM +0100, Rafael J. Wysocki wrote:
> On Tuesday, December 03, 2013 04:28:28 PM Aaron Lu wrote:
> > This patchset converts ACPI fan driver to platform driver. Patch 1-3 are
> > cleanups for existing fan driver and patch 4 does the convertion.
> > 
> > Tested on harris beach.
> > Apply on top of Rafael's linux-next branch.
> > 
> > Aaron Lu (4):
> >   ACPI / fan: remove unused macro for debug
> >   ACPI / fan: remove no need check for device pointer
> >   ACPI / fan: use acpi_device_xxx_power instead of acpi_bus equivelant
> >   ACPI / fan: convert to platform driver
> > 
> >  drivers/acpi/acpi_platform.c |  3 ++
> >  drivers/acpi/device_pm.c     |  1 +
> >  drivers/acpi/fan.c           | 88 ++++++++++++++++----------------------------
> >  drivers/acpi/internal.h      |  2 -
> >  include/acpi/acpi_bus.h      |  1 +
> >  5 files changed, 36 insertions(+), 59 deletions(-)
> 
> Unfortunately, we need to postpone these conversions, because Matthew Garrett
> has problems with adding more entries to acpi_platform_device_ids[].  He seems
> to be concerned that that list will grow indefinitely and will become difficult
> to maintain eventually.
> 
> For this reason, he would prefer it if we did the following:
> - Figure out the list of ACPI device IDs we need to create PNP devices for
>   via ACPI PNP.

I'm not sure how to tell this, is it that as long as the ACPI node has a
PNPxxxx ID we will need to create a PNP device for it? And in this case,
do we only check the _HID or both _HID and _CID?

> - Make ACPI PNP create PNP devices for these IDs only and make the ACPI core create
>   platform devices for all "unassigned" ACPI device objects by default.

Does "unassigned" mean (all ACPI devices) - (ACPI devices that have a
PNP device created already)?

Thanks,
Aaron

> - Do the conversions at that point.
> 
> I'm slightly worried that we'll encounter ordering issues while doing that, but
> this is the only way forward I can see without going straight against the
> Matthew's objections, which I'd prefer to avoid.
> 
> Thanks,
> Rafael
>