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@xxxxxxxxxx>
Acked-by: Rafael J. Wysocki <rjw@xxxxxxx>
> ---
> 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
>
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