Re: [PATCH V2 06/13] ACPI: introduce enumerable_id flag

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
To: Zhang Rui <rui.zhang@intel.com>
Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	bhelgaas@google.com, matthew.garrett@nebula.com,
	dmitry.torokhov@gmail.com
Subject: Re: [PATCH V2 06/13] ACPI: introduce enumerable_id flag
Date: Sat, 15 Mar 2014 02:03:21 +0100	[thread overview]
Message-ID: <5323A6D9.5070005@intel.com> (raw)
In-Reply-To: <1394727413-3587-7-git-send-email-rui.zhang@intel.com>

On 3/13/2014 5:16 PM, Zhang Rui wrote:
> Only certain kind of ACPI device objects can be enumerated via ACPI.
> These ACPI device objects include
> 1. ACPI device objects that have _HID control method.
> 2. some ACPI device objects that have Linux specified HID strings.
>
> In order to distinguish those device objects from the others, a new flag
> enumerable_id and a new function acpi_add_eid() are introduced in this patch.

I don't really like the name of the new flag.  What about calling it 
platform_id (it is supposed to indicate that the core should create a 
platform device for it)?

> Currently, only devices with _HID method have this flag set.
> And in the future, if a device that has Linux specified HID strings
> wants to be enumerated to platform bus, acpi_add_eid() should be used

And what about calling the new function acpi_add_platform_id() accordingly?

> instead of acpi_add_id() when adding its Linux specified HID string.

And I don't quite understand the last paragraph as a whole.  Is it 
supposed to mean "if you want platform devices to be created for device 
objects without _HID, use acpi_add_platform_id() when adding artificial 
Linux-specific ID strings to them"?

> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
> ---
>   drivers/acpi/scan.c     |    8 +++++++-
>   include/acpi/acpi_bus.h |    3 ++-
>   2 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 399257e..768f81d 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1679,6 +1679,12 @@ static void acpi_add_id(struct acpi_device_pnp *pnp, const char *dev_id)
>   	pnp->type.hardware_id = 1;
>   }
>   
> +static void acpi_add_eid(struct acpi_device_pnp *pnp, const char *dev_id)
> +{
> +	acpi_add_id(pnp, dev_id);
> +	pnp->type.enumerable_id = 1;
> +}
> +
>   /*
>    * Old IBM workstations have a DSDT bug wherein the SMBus object
>    * lacks the SMBUS01 HID and the methods do not have the necessary "_"
> @@ -1729,7 +1735,7 @@ static void acpi_set_pnp_ids(acpi_handle handle, struct acpi_device_pnp *pnp,
>   		}
>   
>   		if (info->valid & ACPI_VALID_HID)
> -			acpi_add_id(pnp, info->hardware_id.string);
> +			acpi_add_eid(pnp, info->hardware_id.string);
>   		if (info->valid & ACPI_VALID_CID) {
>   			cid_list = &info->compatible_id_list;
>   			for (i = 0; i < cid_list->count; i++)
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index 8c5e235..688ca44 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -217,7 +217,8 @@ struct acpi_hardware_id {
>   struct acpi_pnp_type {
>   	u32 hardware_id:1;
>   	u32 bus_address:1;
> -	u32 reserved:30;
> +	u32 enumerable_id:1;
> +	u32 reserved:29;
>   };
>   
>   struct acpi_device_pnp {