audiohal: Fix volume changes handling
Some legacy implementations of the effects HAL use the condition
of the reply buffer being NULL as an indication that they shouldn't
apply attenuation to the input audio data. Therefore, separate
methods are needed to distinguish the use cases of delegating the
volume control to the effect, and just informing the effect of the
volume changes.
A new method added to IEffect: volumeChangeNotification that implements
the second use case. The contract of setAndGetVolume method has been
updated to indicate that it is only called in the first use case.
Also updated the wrapper for a generic IEffect commands to pass NULL
pointers to the command and reply buffers in case when the size
of the input or output data is 0, to preserve compatibility with
direct calls from the framework.
Bug: 34368451
Test: volume control works when both Bass Boost and Equalizer are
enabled in the NXP implementation of the effects
Change-Id: I3c9a5bbdff561802bc94080c51703385a8903282
diff --git a/audio/effect/2.0/default/DownmixEffect.h b/audio/effect/2.0/default/DownmixEffect.h
index 1d4c3a9..125f34d 100644
--- a/audio/effect/2.0/default/DownmixEffect.h
+++ b/audio/effect/2.0/default/DownmixEffect.h
@@ -54,6 +54,7 @@
Return<Result> setDevice(AudioDevice device) override;
Return<void> setAndGetVolume(
const hidl_vec<uint32_t>& volumes, setAndGetVolume_cb _hidl_cb) override;
+ Return<Result> volumeChangeNotification(const hidl_vec<uint32_t>& volumes) override;
Return<Result> setAudioMode(AudioMode mode) override;
Return<Result> setConfigReverse(
const EffectConfig& config,