Re: [PATCH 1/6] ACPI: allow drivers to request both device and system notify events

[Len Brown <lenb@kernel.org>]

On Thu, 30 Apr 2009, Bjorn Helgaas wrote:

> System notify events (0x00-0x7f) are common across all device types
> and should be handled in Linux/ACPI, not in drivers.  However, some
> BIOSes use system notify events in device-specific ways that require
> the driver to be involved.
> 
> This patch adds a ACPI_DRIVER_ALL_NOTIFY_EVENTS driver flag.  When a
> driver sets this flag and supplies a .notify method, Linux/ACPI calls
> the .notify method for ALL notify events on the device, not just the
> device-specific (0x80-0xff) events.

What bad things would happen if we did this by default
rather than requiring a driver to ask for it?

thanks,
-Len Brown, Intel Open Source Technology Center

> Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
> ---
>  drivers/acpi/bus.c      |    6 +++++-
>  include/acpi/acpi_bus.h |    3 +++
>  2 files changed, 8 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> index e8f7b64..fd6a930 100644
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -549,6 +549,7 @@ static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
>  {
>  	int result = 0;
>  	struct acpi_device *device = NULL;
> +	struct acpi_driver *driver;
>  
>  	blocking_notifier_call_chain(&acpi_bus_notify_list,
>  		type, (void *)handle);
> @@ -629,7 +630,10 @@ static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
>  		break;
>  	}
>  
> -	return;
> +	driver = device->driver;
> +	if (driver && driver->ops.notify &&
> +	    (driver->flags & ACPI_DRIVER_ALL_NOTIFY_EVENTS))
> +		driver->ops.notify(device, type);
>  }
>  
>  /* --------------------------------------------------------------------------
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index c34b110..84e35d5 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -114,10 +114,13 @@ struct acpi_device_ops {
>  	acpi_op_notify notify;
>  };
>  
> +#define ACPI_DRIVER_ALL_NOTIFY_EVENTS	0x1	/* system AND device events */
> +
>  struct acpi_driver {
>  	char name[80];
>  	char class[80];
>  	const struct acpi_device_id *ids; /* Supported Hardware IDs */
> +	unsigned int flags;
>  	struct acpi_device_ops ops;
>  	struct device_driver drv;
>  	struct module *owner;
>