From 3cf4bfe2368020b50a3e22360910b6af6590c5be Mon Sep 17 00:00:00 2001
From: Dan Stoza <stoza@google.com>
Date: Tue, 2 Aug 2016 10:27:31 -0700
Subject: [PATCH] DO NOT MERGE SF: Add property to disable HWC virtual displays

Adds the property debug.sf.disable_hwc_vds, which will disable the use
of Hardware Composer virtual displays inside SurfaceFlinger (falling
back to SurfaceFlinger management and client composition of such
displays).

Also adds a Binder debug interface for controlling this behavior.

Bug: 30510632
Change-Id: I2c1a199213a24195b144bfa0c0f1679f2dfd0668
---
 services/surfaceflinger/SurfaceFlinger.cpp      | 51 +++++++++++++++----------
 services/surfaceflinger/SurfaceFlinger.h        |  1 +
 services/surfaceflinger/SurfaceFlinger_hwc1.cpp | 14 ++++++-
 3 files changed, 44 insertions(+), 22 deletions(-)

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 820c332a9c..3ec3cc2686 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -183,6 +183,10 @@ SurfaceFlinger::SurfaceFlinger()
     property_get("debug.sf.disable_backpressure", value, "0");
     mPropagateBackpressure = !atoi(value);
     ALOGI_IF(!mPropagateBackpressure, "Disabling backpressure propagation");
+
+    property_get("debug.sf.disable_hwc_vds", value, "0");
+    mUseHwcVirtualDisplays = !atoi(value);
+    ALOGI_IF(!mUseHwcVirtualDisplays, "Disabling HWC virtual displays");
 }
 
 void SurfaceFlinger::onFirstRef()
@@ -1582,26 +1586,28 @@ void SurfaceFlinger::handleTransactionLocked(uint32_t transactionFlags)
                         // etc.) but no internal state (i.e. a DisplayDevice).
                         if (state.surface != NULL) {
 
-                            int width = 0;
-                            int status = state.surface->query(
-                                    NATIVE_WINDOW_WIDTH, &width);
-                            ALOGE_IF(status != NO_ERROR,
-                                    "Unable to query width (%d)", status);
-                            int height = 0;
-                            status = state.surface->query(
-                                    NATIVE_WINDOW_HEIGHT, &height);
-                            ALOGE_IF(status != NO_ERROR,
-                                    "Unable to query height (%d)", status);
-                            int intFormat = 0;
-                            status = state.surface->query(
-                                    NATIVE_WINDOW_FORMAT, &intFormat);
-                            ALOGE_IF(status != NO_ERROR,
-                                    "Unable to query format (%d)", status);
-                            auto format = static_cast<android_pixel_format_t>(
-                                    intFormat);
-
-                            mHwc->allocateVirtualDisplay(width, height, &format,
-                                    &hwcId);
+                            if (mUseHwcVirtualDisplays) {
+                                int width = 0;
+                                int status = state.surface->query(
+                                        NATIVE_WINDOW_WIDTH, &width);
+                                ALOGE_IF(status != NO_ERROR,
+                                        "Unable to query width (%d)", status);
+                                int height = 0;
+                                status = state.surface->query(
+                                        NATIVE_WINDOW_HEIGHT, &height);
+                                ALOGE_IF(status != NO_ERROR,
+                                        "Unable to query height (%d)", status);
+                                int intFormat = 0;
+                                status = state.surface->query(
+                                        NATIVE_WINDOW_FORMAT, &intFormat);
+                                ALOGE_IF(status != NO_ERROR,
+                                        "Unable to query format (%d)", status);
+                                auto format = static_cast<android_pixel_format_t>(
+                                        intFormat);
+
+                                mHwc->allocateVirtualDisplay(width, height, &format,
+                                        &hwcId);
+                            }
 
                             // TODO: Plumb requested format back up to consumer
 
@@ -3277,6 +3283,11 @@ status_t SurfaceFlinger::onTransact(
                 mSFEventThread->setPhaseOffset(static_cast<nsecs_t>(n));
                 return NO_ERROR;
             }
+            case 1021: { // Disable HWC virtual displays
+                n = data.readInt32();
+                mUseHwcVirtualDisplays = !n;
+                return NO_ERROR;
+            }
         }
     }
     return err;
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index f50f9e7918..65e0cbf811 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -529,6 +529,7 @@ private:
 #ifdef USE_HWC2
     bool mPropagateBackpressure = true;
 #endif
+    bool mUseHwcVirtualDisplays = true;
 
     // these are thread safe
     mutable MessageQueue mEventQueue;
diff --git a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
index 34240b4dd3..3a65e85463 100644
--- a/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
+++ b/services/surfaceflinger/SurfaceFlinger_hwc1.cpp
@@ -181,6 +181,10 @@ SurfaceFlinger::SurfaceFlinger()
     }
     ALOGI_IF(mDebugRegion, "showupdates enabled");
     ALOGI_IF(mDebugDDMS, "DDMS debugging enabled");
+
+    property_get("debug.sf.disable_hwc_vds", value, "0");
+    mUseHwcVirtualDisplays = !atoi(value);
+    ALOGI_IF(!mUseHwcVirtualDisplays, "Disabling HWC virtual displays");
 }
 
 void SurfaceFlinger::onFirstRef()
@@ -1508,9 +1512,10 @@ void SurfaceFlinger::handleTransactionLocked(uint32_t transactionFlags)
                                     NATIVE_WINDOW_HEIGHT, &height);
                             ALOGE_IF(status != NO_ERROR,
                                     "Unable to query height (%d)", status);
-                            if (MAX_VIRTUAL_DISPLAY_DIMENSION == 0 ||
+                            if (mUseHwcVirtualDisplays &&
+                                    (MAX_VIRTUAL_DISPLAY_DIMENSION == 0 ||
                                     (width <= MAX_VIRTUAL_DISPLAY_DIMENSION &&
-                                     height <= MAX_VIRTUAL_DISPLAY_DIMENSION)) {
+                                     height <= MAX_VIRTUAL_DISPLAY_DIMENSION))) {
                                 hwcDisplayId = allocateHwcDisplayId(state.type);
                             }
 
@@ -3191,6 +3196,11 @@ status_t SurfaceFlinger::onTransact(
                 mSFEventThread->setPhaseOffset(static_cast<nsecs_t>(n));
                 return NO_ERROR;
             }
+            case 1021: { // Disable HWC virtual displays
+                n = data.readInt32();
+                mUseHwcVirtualDisplays = !n;
+                return NO_ERROR;
+            }
         }
     }
     return err;
-- 
2.11.0