commit 4b4cb8dab3ae8d0cc01af25984473799bbf939c9
author Erik Staats <estaats@google.com> Fri Dec 10 12:20:22 2021 -0800
committer Erik Staats <estaats@google.com> Fri Dec 10 12:20:22 2021 -0800
tree b1113aeae92785138b5bce3466b3c6e3a7c416e7
parent 0d8677fa4d1861f1596538fff8db887ad0fc12b6

dynamic_sensor: Fix report item offset calculation.

Bug: 207008609
Test: Verified dynamic sensor sampling with proposed standard Android
 head tracker.
Change-Id: I163b79c2c99f02961adebcb5dcb7e39603944e24

modules/sensors/dynamic_sensor/HidUtils/HidParser.cpp

diff --git a/modules/sensors/dynamic_sensor/HidUtils/HidParser.cpp b/modules/sensors/dynamic_sensor/HidUtils/HidParser.cpp
index 28d87d9..19aa429 100644
--- a/modules/sensors/dynamic_sensor/HidUtils/HidParser.cpp
+++ b/modules/sensors/dynamic_sensor/HidUtils/HidParser.cpp
@@ -240,10 +240,12 @@
                 auto logical = r.getLogicalRange();
                 auto physical = r.getPhysicalRange();
 
-                int64_t offset = physical.first - logical.first;
                 double scale = static_cast<double>((physical.second - physical.first))
                         / (logical.second - logical.first);
                 scale *= r.getExponentValue();
+                int64_t offset =
+                        (physical.first * r.getExponentValue() / scale) -
+                        logical.first;
 
                 ReportItem digest = {
                     .usage = r.getFullUsage(),