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SubjectRe: [PATCH] ACPI / scan: Add a scan handler for PRP0001
On Sat, Apr 11, 2015 at 01:28:45AM +0200, Rafael Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> If the special PRP0001 device ID is present in the given device's list
> of ACPI/PNP IDs and the device has a valid "compatible" property in
> the _DSD, it should be enumerated using the default mechanism,
> unless some scan handlers match the IDs preceding PRP0001 in the
> device's list of ACPI/PNP IDs. In particular, no scan handlers
> matching the IDs following PRP0001 in that list should be attached
> to the device.
>
> To make that happen, define a scan handler that will match PRP0001
> and trigger the default enumeration for the matching devices if the
> "compatible" property is present for them.
>
> Since that requires the check for platform_id and device->handler
> to be removed from acpi_default_enumeration(), move the fallback
> invocation of acpi_default_enumeration() to acpi_bus_attach()
> (after it's checked if there's a matching ACPI driver for the
> device), which is a better place to call it, and do the platform_id
> check in there too (device->handler is guaranteed to be unset at
> the point where the function is looking for a matching ACPI driver).
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/acpi/scan.c | 34 +++++++++++++++++++++++++++++-----
> 1 file changed, 29 insertions(+), 5 deletions(-)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -2390,9 +2390,6 @@ static void acpi_default_enumeration(str
> struct list_head resource_list;
> bool is_spi_i2c_slave = false;
>
> - if (!device->pnp.type.platform_id || device->handler)
> - return;
> -
> /*
> * Do not enemerate SPI/I2C slaves as they will be enuerated by their
> * respective parents.
> @@ -2405,6 +2402,30 @@ static void acpi_default_enumeration(str
> acpi_create_platform_device(device);
> }
>
> +static const struct acpi_device_id generic_device_ids[] = {
> + {"PRP0001", },
> + {"", },
> +};
> +
> +static int acpi_generic_device_attach(struct acpi_device *adev,
> + const struct acpi_device_id *not_used)
> +{
> + /*
> + * Since PRP0001 is the only ID handled here, the test below can be
> + * unconditional.
> + */
> + if (adev->data.of_compatible) {
> + acpi_default_enumeration(adev);
> + return 1;
> + }

Would a warning be appropriate here? PRP0001 should only appear when paired with
a DSD of GUID Device Properties with a "compatible" entry. If not, it's an
error, correct? I believe we warn on similarly malformed AML?

Otherwise,

Acked-by: Darren Hart <dvhart@linux.intel.com>

--
Darren Hart
Intel Open Source Technology Center


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