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camera_common: change torch status callback API

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Update the torch status callback API so that HAL must invoke
the torch status callback whenever the torch status changes
including changes by set_torch_mode().

The problem of the previous approach was camera service needed
to invoke the callback after calling set_torch_mode() and two
sources of the torch status changes (HAL and camera service)
caused a race condition.

Add STATUS_ON and remove STATUS_AVAILABLE which isn't useful
because STATUS_OFF means torch is off and available. STATUS_ON
means torch is on and available.

Bug: 2682206
Change-Id: Ide5d289c5f485404a3ba46e6cb359fa8a52da0bb
This commit is contained in:
Chien-Yu Chen
2015-02-25 14:50:13 -08:00
parent 3a6417d165
commit 8558510d59
1 changed files with 31 additions and 28 deletions
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59
include/hardware/camera_common.h
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@@ -391,7 +391,7 @@ typedef enum camera_device_status {
* device is present. The framework will not call set_torch_mode() to turn on
* torch mode of a camera device if the camera device is not present. At module
* load time, the framework will assume torch modes are in the
* TORCH_MODE_STATUS_AVAILABLE state if the camera device is present and
* TORCH_MODE_STATUS_OFF state if the camera device is present and
* android.flash.info.available is reported as true via get_camera_info() call.
*
* The behaviors of the camera HAL module that the framework expects in the
@@ -400,7 +400,7 @@ typedef enum camera_device_status {
* After camera_module_callbacks::camera_device_status_change() is invoked
* to inform the framework that the camera device is present, the framework
* will assume the camera device's torch mode is in
* TORCH_MODE_STATUS_AVAILABLE state. The camera HAL module does not need
* TORCH_MODE_STATUS_OFF state. The camera HAL module does not need
* to invoke camera_module_callbacks::torch_mode_status_change() unless the
* flash unit is unavailable to use by set_torch_mode().
*
@@ -416,47 +416,49 @@ typedef enum camera_device_status {
* 3. open() is called to open a camera device.
* The camera HAL module must invoke
* camera_module_callbacks::torch_mode_status_change() for all flash units
* that have entered TORCH_MODE_STATUS_RESOURCE_BUSY state and can not be
* that have entered TORCH_MODE_STATUS_NOT_AVAILABLE state and can not be
* turned on by calling set_torch_mode() anymore due to this open() call.
*
* 4. close() is called to close a camera device.
* The camera HAL module must invoke
* camera_module_callbacks::torch_mode_status_change() for all flash units
* that have entered TORCH_MODE_STATUS_AVAILABLE state and can be turned
* that have entered TORCH_MODE_STATUS_OFF state and can be turned
* on by calling set_torch_mode() again because of enough resources freed
* up by this close() call.
*
* Note that the framework calling set_torch_mode() should not trigger any
* callbacks except when HAL cannot keep multiple torch modes on
* simultaneously. In that case, HAL must notify the framework that any
* previously-on torch mode states have become TORCH_MODE_STATUS_OFF.
*
* Note that the framework calling set_torch_mode() successfully must trigger
* TORCH_MODE_STATUS_OFF or TORCH_MODE_STATUS_ON callback for the given camera
* device. Additionally it must trigger TORCH_MODE_STATUS_OFF callbacks for
* other previously-on torch modes if HAL cannot keep multiple torch modes on
* simultaneously.
*/
typedef enum torch_mode_status {
/**
* The flash unit is available and the torch mode can be turned on by
* calling set_torch_mode(). By default, the framework will assume all
* flash units of all present camera devices are in this state if
* android.flash.info.available is reported as true via get_camera_info()
* call.
*/
TORCH_MODE_STATUS_AVAILABLE = 0,
/**
* The flash unit is no longer available and the torch mode can not be
* turned on by calling set_torch_mode(). If the torch mode is on, it
* will be turned off by HAL before HAL calls torch_mode_status_change().
*/
TORCH_MODE_STATUS_RESOURCE_BUSY = 1,
TORCH_MODE_STATUS_NOT_AVAILABLE = 0,
/**
* The previously-on torch mode has been turned off by HAL but the flash
* unit is still available for set_torch_mode(). This may happen after the
* framework turned on the torch mode of some other camera device and HAL
* had to turn off the torch modes of any camera devices that were
* previously on.
* A torch mode has become off and available to be turned on via
* set_torch_mode(). This may happen in the following
* cases:
* 1. After the resources to turn on the torch mode have become available.
* 2. After set_torch_mode() is called to turn off the torch mode.
* 3. After the framework turned on the torch mode of some other camera
* device and HAL had to turn off the torch modes of any camera devices
* that were previously on.
*/
TORCH_MODE_STATUS_OFF = 2,
TORCH_MODE_STATUS_AVAILABLE_OFF = 1,
/**
* A torch mode has become on and available to be turned off via
* set_torch_mode(). This can happen only after set_torch_mode() is called
* to turn on the torch mode.
*/
TORCH_MODE_STATUS_AVAILABLE_ON = 2,
} torch_mode_status_t;
@@ -713,18 +715,19 @@ typedef struct camera_module {
* set_torch_mode:
*
* Turn on or off the torch mode of the flash unit associated with a given
* camera ID. This function is blocking until the operation completes or
* fails.
* camera ID. If the operation is successful, HAL must notify the framework
* torch state by invoking
* camera_module_callbacks.torch_mode_status_change() with the new state.
*
* The camera device has a higher priority accessing the flash unit. When
* there are any resource conflicts, such as open() is called to open a
* camera device, HAL module must notify the framework through
* camera_module_callbacks.torch_mode_status_change() that the
* torch mode has been turned off and the torch mode state has become
* TORCH_MODE_STATUS_RESOURCE_BUSY. When resources to turn on torch mode
* TORCH_MODE_STATUS_NOT_AVAILABLE. When resources to turn on torch mode
* become available again, HAL module must notify the framework through
* camera_module_callbacks.torch_mode_status_change() that the torch mode
* state has become available for set_torch_mode() to be called.
* state has become TORCH_MODE_STATUS_OFF for set_torch_mode() to be called.
*
* When the framework calls set_torch_mode() to turn on the torch mode of a
* flash unit, if HAL cannot keep multiple torch modes on simultaneously,