Add flag for multi-device input

For now, this flag will simply bypass the PreferStylusOverTouchBlocker.
In the future, we can look into possibly turning on/off parts of the
dispatcher with this flag, as well.

Test: atest inputflinger_tests
Bug: 211379801
Change-Id: I9ec6a42bf2cb9671cf3ca179995698dbae1dcc34

2 files changed, 18 insertions, 4 deletions

diff --git a/libs/input/input_flags.aconfig b/libs/input/input_flags.aconfig
index a0563f916d..e8575a6103 100644
--- a/libs/input/input_flags.aconfig
+++ b/libs/input/input_flags.aconfig
@@ -27,3 +27,10 @@ flag {
   description: "Set to true to enable timer support for the touchpad Gestures library"
   bug: "297192727"
 }
+
+flag {
+  name: "enable_multi_device_input"
+  namespace: "input"
+  description: "Set to true to enable multi-device input: touch and stylus can be active at the same time, but in different windows"
+  bug: "211379801"
+}
diff --git a/services/inputflinger/UnwantedInteractionBlocker.cpp b/services/inputflinger/UnwantedInteractionBlocker.cpp
index f889de58b8..0f6232477e 100644
--- a/services/inputflinger/UnwantedInteractionBlocker.cpp
+++ b/services/inputflinger/UnwantedInteractionBlocker.cpp
@@ -18,6 +18,7 @@
 #include "UnwantedInteractionBlocker.h"
 
 #include <android-base/stringprintf.h>
+#include <com_android_input_flags.h>
 #include <ftl/enum.h>
 #include <input/PrintTools.h>
 #include <inttypes.h>
@@ -28,6 +29,8 @@
 #include "ui/events/ozone/evdev/touch_filter/neural_stylus_palm_detection_filter.h"
 #include "ui/events/ozone/evdev/touch_filter/palm_model/onedevice_train_palm_detection_filter_model.h"
 
+namespace input_flags = com::android::input::flags;
+
 using android::base::StringPrintf;
 
 /**
@@ -344,10 +347,14 @@ void UnwantedInteractionBlocker::notifyMotion(const NotifyMotionArgs& args) {
     ALOGD_IF(DEBUG_INBOUND_MOTION, "%s: %s", __func__, args.dump().c_str());
     { // acquire lock
         std::scoped_lock lock(mLock);
-        const std::vector<NotifyMotionArgs> processedArgs =
-                mPreferStylusOverTouchBlocker.processMotion(args);
-        for (const NotifyMotionArgs& loopArgs : processedArgs) {
-            notifyMotionLocked(loopArgs);
+        if (input_flags::enable_multi_device_input()) {
+            notifyMotionLocked(args);
+        } else {
+            const std::vector<NotifyMotionArgs> processedArgs =
+                    mPreferStylusOverTouchBlocker.processMotion(args);
+            for (const NotifyMotionArgs& loopArgs : processedArgs) {
+                notifyMotionLocked(loopArgs);
+            }
         }
     } // release lock