commit ab3c5c53d99c2637f87e37a029018850286bad3d
author Sushil Chauhan <sushilchauhan@codeaurora.org> Fri Jul 12 14:54:29 2019 -0700
committer Gerrit - the friendly Code Review server <code-review@localhost> Fri Jul 19 14:04:11 2019 -0700
tree 26b504fa468261638aca97a1bd9a6b99d639c05c
parent 5b39caac3971ec4a245fa32ebf40d45df71e0e33

sdm: Don't block draw-cycle thread during SetDisplayBrightness

Driver makes sure that Panel commands are serialized to any frame
update on Panel. SetDisplayBrightness API doesn't need to acquire
locker_ lock which blocks draw-cycle thread and causes frame drops.
Define brightness_lock_ to serialize Set and Get Panel brightness.

CRs-Fixed: 2446089
Change-Id: I963f1b3ddcd4765ddff805a373f70cdd550fa993

composer/hwc_session.cpp

diff --git a/composer/hwc_session.cpp b/composer/hwc_session.cpp
index d2f61c5..40a21d7 100644
--- a/composer/hwc_session.cpp
+++ b/composer/hwc_session.cpp
@@ -2910,7 +2910,15 @@
 }
 
 int32_t HWCSession::SetDisplayBrightness(hwc2_display_t display, float brightness) {
-  return CallDisplayFunction(display, &HWCDisplay::SetPanelBrightness, brightness);
+  if (display >= HWCCallbacks::kNumDisplays) {
+    return HWC2_ERROR_BAD_DISPLAY;
+  }
+
+  if (!hwc_display_[display]) {
+    return HWC2_ERROR_BAD_PARAMETER;
+  }
+
+  return INT32(hwc_display_[display]->SetPanelBrightness(brightness));
 }
 
 android::status_t HWCSession::SetQSyncMode(const android::Parcel *input_parcel) {

sdm/libs/core/display_builtin.cpp

diff --git a/sdm/libs/core/display_builtin.cpp b/sdm/libs/core/display_builtin.cpp
index 8d7529a..267a4d7 100644
--- a/sdm/libs/core/display_builtin.cpp
+++ b/sdm/libs/core/display_builtin.cpp
@@ -285,7 +285,7 @@
 }
 
 DisplayError DisplayBuiltIn::SetPanelBrightness(float brightness) {
-  lock_guard<recursive_mutex> obj(recursive_mutex_);
+  lock_guard<recursive_mutex> obj(brightness_lock_);
 
   if (brightness != -1.0f && !(0.0f <= brightness && brightness <= 1.0f)) {
     DLOGE("Bad brightness value = %f", brightness);
@@ -441,7 +441,7 @@
 }
 
 DisplayError DisplayBuiltIn::GetPanelBrightness(float *brightness) {
-  lock_guard<recursive_mutex> obj(recursive_mutex_);
+  lock_guard<recursive_mutex> obj(brightness_lock_);
 
   DisplayError err = kErrorNone;
   int level = 0;

sdm/libs/core/display_builtin.h

diff --git a/sdm/libs/core/display_builtin.h b/sdm/libs/core/display_builtin.h
index 6fe7b34..3a0e887 100644
--- a/sdm/libs/core/display_builtin.h
+++ b/sdm/libs/core/display_builtin.h
@@ -112,6 +112,7 @@
   float level_remainder_ = 0.0f;
   float cached_brightness_ = 0.0f;
   bool pending_brightness_ = false;
+  recursive_mutex brightness_lock_;
 };
 
 }  // namespace sdm