From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: [PATCH 6/13] ACPI / PM: Introduce __acpi_bus_get_power() Date: Thu, 25 Nov 2010 00:07:56 +0100 Message-ID: <201011250007.56895.rjw@sisk.pl> References: <201011250001.11297.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <201011250001.11297.rjw@sisk.pl> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Len Brown Cc: ACPI Devel Maling List , Linux-pm mailing list , Maciej Rutecki , LKML List-Id: linux-pm@vger.kernel.org From: Rafael J. Wysocki It sometimes is necessary to get the power state of an ACPI device without updating its device->power.state field, for example to avoid inconsistencies between device->power.state and the reference counters of the device's power resources. For this purpose introduce __acpi_bus_get_power() that will return the given device's power state via a pointer (instead of modifying device->power.state) and make acpi_bus_get_power() use it. Signed-off-by: Rafael J. Wysocki --- drivers/acpi/bus.c | 48 +++++++++++++++++++++++++++++------------------- 1 file changed, 29 insertions(+), 19 deletions(-) Index: linux-2.6/drivers/acpi/bus.c =================================================================== --- linux-2.6.orig/drivers/acpi/bus.c +++ linux-2.6/drivers/acpi/bus.c @@ -196,34 +196,24 @@ EXPORT_SYMBOL(acpi_bus_get_private_data) Power Management -------------------------------------------------------------------------- */ -int acpi_bus_get_power(acpi_handle handle, int *state) +static int __acpi_bus_get_power(struct acpi_device *device, int *state) { int result = 0; acpi_status status = 0; - struct acpi_device *device = NULL; unsigned long long psc = 0; - - result = acpi_bus_get_device(handle, &device); - if (result) - return result; + if (!device || !state) + return -EINVAL; *state = ACPI_STATE_UNKNOWN; - if (!device->flags.power_manageable) { - /* TBD: Non-recursive algorithm for walking up hierarchy */ - if (device->parent) - *state = device->parent->power.state; - else - *state = ACPI_STATE_D0; - } else { + if (device->flags.power_manageable) { /* * Get the device's power state either directly (via _PSC) or * indirectly (via power resources). */ if (device->power.flags.power_resources) { - result = acpi_power_get_inferred_state(device, - &device->power.state); + result = acpi_power_get_inferred_state(device, state); if (result) return result; } else if (device->power.flags.explicit_get) { @@ -231,20 +221,40 @@ int acpi_bus_get_power(acpi_handle handl NULL, &psc); if (ACPI_FAILURE(status)) return -ENODEV; - device->power.state = (int)psc; + *state = (int)psc; } - - *state = device->power.state; + } else { + /* TBD: Non-recursive algorithm for walking up hierarchy. */ + *state = device->parent ? + device->parent->power.state : ACPI_STATE_D0; } ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is D%d\n", - device->pnp.bus_id, device->power.state)); + device->pnp.bus_id, *state)); return 0; } + +int acpi_bus_get_power(acpi_handle handle, int *state) +{ + struct acpi_device *device; + int result; + + result = acpi_bus_get_device(handle, &device); + if (result) + return result; + + result = __acpi_bus_get_power(device, state); + if (result) + return result; + + device->power.state = *state; + return 0; +} EXPORT_SYMBOL(acpi_bus_get_power); + int acpi_bus_set_power(acpi_handle handle, int state) { int result = 0;