Re: [PATCH 2/3] acpica: Add support for unregistering ACPI GPE methods

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Monday 09 November 2009, Matthew Garrett wrote:
> Some vendors ship firmware with untested GPE handlers. The presence of
> these handlers may be sufficient to cause the OS to assume that runtime
> power management of the associated devices is possible, potentially
> resulting in devices being powered down and no wakeup events ever being
> generated.
> 
> The simplest solution is to add support for the OS to unhook these GPE
> methods when it knows that they are broken. Add a function to the ACPICA
> code to allow this.
> 
> Signed-off-by: Matthew Garrett <mjg@redhat.com>

Acked-by: Rafael J. Wysocki <rjw@sisk.pl>

> ---
>  drivers/acpi/acpica/evxface.c |   69 +++++++++++++++++++++++++++++++++++++++++
>  include/acpi/acpixf.h         |    3 ++
>  2 files changed, 72 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/acpi/acpica/evxface.c b/drivers/acpi/acpica/evxface.c
> index 90cdeae..33b1dc0 100644
> --- a/drivers/acpi/acpica/evxface.c
> +++ b/drivers/acpi/acpica/evxface.c
> @@ -736,6 +736,75 @@ ACPI_EXPORT_SYMBOL(acpi_remove_gpe_handler)
>  
>  /*******************************************************************************
>   *
> + * FUNCTION:    acpi_remove_gpe_method
> + *
> + * PARAMETERS:  gpe_device      - Namespace node for the GPE (NULL for FADT
> + *                                defined GPEs)
> + *              gpe_number      - The event to remove a handler
> + *
> + * RETURN:      Status
> + *
> + * DESCRIPTION: Remove the method for a General Purpose acpi_event.
> + *
> + ******************************************************************************/
> +acpi_status
> +acpi_remove_gpe_method(acpi_handle gpe_device, u32 gpe_number)
> +{
> +	struct acpi_gpe_event_info *gpe_event_info;
> +	acpi_status status;
> +	acpi_cpu_flags flags;
> +
> +	ACPI_FUNCTION_TRACE(acpi_remove_gpe_method);
> +
> +	/* Parameter validation */
> +
> +	status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
> +	if (ACPI_FAILURE(status)) {
> +		return_ACPI_STATUS(status);
> +	}
> +
> +	/* Ensure that we have a valid GPE number */
> +
> +	gpe_event_info = acpi_ev_get_gpe_event_info(gpe_device, gpe_number);
> +	if (!gpe_event_info) {
> +		status = AE_BAD_PARAMETER;
> +		goto unlock_and_exit;
> +	}
> +
> +	/* Make sure that a method is indeed installed */
> +
> +	if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) !=
> +	    ACPI_GPE_DISPATCH_METHOD) {
> +		status = AE_NOT_EXIST;
> +		goto unlock_and_exit;
> +	}
> +
> +	/* Make sure all deferred tasks are completed */
> +
> +	(void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
> +	acpi_os_wait_events_complete(NULL);
> +	status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
> +	if (ACPI_FAILURE(status)) {
> +		return_ACPI_STATUS(status);
> +	}
> +
> +	/* Remove the method */
> +
> +	flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
> +	gpe_event_info->dispatch.method_node = NULL;
> +	gpe_event_info->flags &= ~ACPI_GPE_DISPATCH_METHOD;
> +
> +	acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
> +
> +      unlock_and_exit:
> +	(void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
> +	return_ACPI_STATUS(status);
> +}
> +
> +ACPI_EXPORT_SYMBOL(acpi_remove_gpe_method)
> +
> +/*******************************************************************************
> + *
>   * FUNCTION:    acpi_acquire_global_lock
>   *
>   * PARAMETERS:  Timeout         - How long the caller is willing to wait
> diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
> index bb3c975..f89aa7b 100644
> --- a/include/acpi/acpixf.h
> +++ b/include/acpi/acpixf.h
> @@ -258,6 +258,9 @@ acpi_status
>  acpi_remove_gpe_handler(acpi_handle gpe_device,
>  			u32 gpe_number, acpi_event_handler address);
>  
> +acpi_status
> +acpi_remove_gpe_method(acpi_handle gpe_device, u32 gpe_number);
> +
>  #ifdef ACPI_FUTURE_USAGE
>  acpi_status acpi_install_exception_handler(acpi_exception_handler handler);
>  #endif
>