commit 8cf150a0341768133b37cd9c6f2369bf6f79a943
author Dan Stoza <stoza@google.com> Tue Aug 02 10:27:31 2016 -0700
committer Dan Stoza <stoza@google.com> Wed Aug 10 12:44:10 2016 -0700
tree c0507255c59a10f544de6e6ba355fb7de975a411
parent 5885800d1977adf414fea5df93077543a22b754b

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

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index cd570e7..f3d31d9 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -198,6 +198,10 @@
     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()
@@ -1655,26 +1659,28 @@
                         // 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);
+                            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);
+                                mHwc->allocateVirtualDisplay(width, height, &format,
+                                        &hwcId);
+                            }
 
                             // TODO: Plumb requested format back up to consumer
 
@@ -3365,6 +3371,11 @@
                 }
                 return NO_ERROR;
             }
+            case 1021: { // Disable HWC virtual displays
+                n = data.readInt32();
+                mUseHwcVirtualDisplays = !n;
+                return NO_ERROR;
+            }
         }
     }
     return err;