Clean up HWC state when releasing a DisplayDevice

DisplayDevices can be released when DisplayManager removes them from
the display list, or (for virtual displays) when the surface is set to
NULL. We were only cleaning up HWC resources associated with the
display in the first case.

Bug: 8384764
Change-Id: Id3d226dd7178fbe6d0a2ac4e2660b864ee073de3

5 files changed, 38 insertions, 17 deletions

diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index 6936a7f..68b0b7f 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -143,6 +143,15 @@ DisplayDevice::~DisplayDevice() {
     }
 }
 
+void DisplayDevice::disconnect(HWComposer& hwc) {
+    if (mHwcDisplayId >= 0) {
+        hwc.disconnectDisplay(mHwcDisplayId);
+        if (mHwcDisplayId >= DISPLAY_VIRTUAL)
+            hwc.freeDisplayId(mHwcDisplayId);
+        mHwcDisplayId = -1;
+    }
+}
+
 bool DisplayDevice::isValid() const {
     return mFlinger != NULL;
 }
@@ -419,11 +428,11 @@ void DisplayDevice::dump(String8& result, char* buffer, size_t SIZE) const {
     const Transform& tr(mGlobalTransform);
     snprintf(buffer, SIZE,
         "+ DisplayDevice: %s\n"
-        "   type=%x, layerStack=%u, (%4dx%4d), ANativeWindow=%p, orient=%2d (type=%08x), "
+        "   type=%x, hwcId=%d, layerStack=%u, (%4dx%4d), ANativeWindow=%p, orient=%2d (type=%08x), "
         "flips=%u, isSecure=%d, secureVis=%d, acquired=%d, numLayers=%u\n"
         "   v:[%d,%d,%d,%d], f:[%d,%d,%d,%d], s:[%d,%d,%d,%d],"
         "transform:[[%0.3f,%0.3f,%0.3f][%0.3f,%0.3f,%0.3f][%0.3f,%0.3f,%0.3f]]\n",
-        mDisplayName.string(), mType,
+        mDisplayName.string(), mType, mHwcDisplayId,
         mLayerStack, mDisplayWidth, mDisplayHeight, mNativeWindow.get(),
         mOrientation, tr.getType(), getPageFlipCount(),
         mIsSecure, mSecureLayerVisible, mScreenAcquired, mVisibleLayersSortedByZ.size(),
diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index d4a6daa..377d924 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -146,6 +146,9 @@ public:
     bool isScreenAcquired() const;
     bool canDraw() const;
 
+    // release HWC resources (if any) for removable displays
+    void disconnect(HWComposer& hwc);
+
     /* ------------------------------------------------------------------------
      * Debugging
      */
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index 497593b..86e674a 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -953,17 +953,17 @@ void HWComposer::dump(String8& result, char* buffer, size_t SIZE) const {
         result.appendFormat("  mDebugForceFakeVSync=%d\n", mDebugForceFakeVSync);
         for (size_t i=0 ; i<mNumDisplays ; i++) {
             const DisplayData& disp(mDisplayData[i]);
+            if (!disp.connected)
+                continue;
 
             const Vector< sp<Layer> >& visibleLayersSortedByZ =
                     mFlinger->getLayerSortedByZForHwcDisplay(i);
 
-            if (disp.connected) {
-                result.appendFormat(
-                        "  Display[%d] : %ux%u, xdpi=%f, ydpi=%f, refresh=%lld\n",
-                        i, disp.width, disp.height, disp.xdpi, disp.ydpi, disp.refresh);
-            }
+            result.appendFormat(
+                    "  Display[%d] : %ux%u, xdpi=%f, ydpi=%f, refresh=%lld\n",
+                    i, disp.width, disp.height, disp.xdpi, disp.ydpi, disp.refresh);
 
-            if (disp.list && disp.connected) {
+            if (disp.list) {
                 result.appendFormat(
                         "  numHwLayers=%u, flags=%08x\n",
                         disp.list->numHwLayers, disp.list->flags);
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 0a210f7..ed6574a 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1102,12 +1102,14 @@ void SurfaceFlinger::handleTransactionLocked(uint32_t transactionFlags)
                         // Call makeCurrent() on the primary display so we can
                         // be sure that nothing associated with this display
                         // is current.
-                        const sp<const DisplayDevice> hw(getDefaultDisplayDevice());
-                        DisplayDevice::makeCurrent(mEGLDisplay, hw, mEGLContext);
-                        mDisplays.removeItem(draw.keyAt(i));
-                        getHwComposer().disconnectDisplay(draw[i].type);
+                        const sp<const DisplayDevice> defaultDisplay(getDefaultDisplayDevice());
+                        DisplayDevice::makeCurrent(mEGLDisplay, defaultDisplay, mEGLContext);
+                        sp<DisplayDevice> hw(getDisplayDevice(draw.keyAt(i)));
+                        if (hw != NULL)
+                            hw->disconnect(getHwComposer());
                         if (draw[i].type < DisplayDevice::NUM_DISPLAY_TYPES)
                             mEventThread->onHotplugReceived(draw[i].type, false);
+                        mDisplays.removeItem(draw.keyAt(i));
                     } else {
                         ALOGW("trying to remove the main display");
                     }
@@ -1120,6 +1122,9 @@ void SurfaceFlinger::handleTransactionLocked(uint32_t transactionFlags)
                         // recreating the DisplayDevice, so we just remove it
                         // from the drawing state, so that it get re-added
                         // below.
+                        sp<DisplayDevice> hw(getDisplayDevice(display));
+                        if (hw != NULL)
+                            hw->disconnect(getHwComposer());
                         mDisplays.removeItem(display);
                         mDrawingState.displays.removeItemsAt(i);
                         dc--; i--;
@@ -1150,9 +1155,13 @@ void SurfaceFlinger::handleTransactionLocked(uint32_t transactionFlags)
                     const DisplayDeviceState& state(curr[i]);
 
                     sp<DisplaySurface> dispSurface;
-                    int32_t hwcDisplayId = allocateHwcDisplayId(state.type);
+                    int32_t hwcDisplayId = -1;
                     if (state.isVirtualDisplay()) {
+                        // Virtual displays without a surface are dormant:
+                        // they have external state (layer stack, projection,
+                        // etc.) but no internal state (i.e. a DisplayDevice).
                         if (state.surface != NULL) {
+                            hwcDisplayId = allocateHwcDisplayId(state.type);
                             dispSurface = new VirtualDisplaySurface(
                                     *mHwc, hwcDisplayId, state.surface,
                                     state.displayName);
@@ -1162,7 +1171,7 @@ void SurfaceFlinger::handleTransactionLocked(uint32_t transactionFlags)
                                 "adding a supported display, but rendering "
                                 "surface is provided (%p), ignoring it",
                                 state.surface.get());
-
+                        hwcDisplayId = allocateHwcDisplayId(state.type);
                         // for supported (by hwc) displays we provide our
                         // own rendering surface
                         dispSurface = new FramebufferSurface(*mHwc, state.type);
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index f0e6deb..57ee8b9 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -108,9 +108,6 @@ public:
     // utility function to delete a texture on the main thread
     void deleteTextureAsync(GLuint texture);
 
-    // allocate a h/w composer display id
-    int32_t allocateHwcDisplayId(DisplayDevice::DisplayType type);
-
     // enable/disable h/w composer event
     // TODO: this should be made accessible only to EventThread
     void eventControl(int disp, int event, int enabled);
@@ -338,6 +335,9 @@ private:
     // region of all screens presenting this layer stack.
     void invalidateLayerStack(uint32_t layerStack, const Region& dirty);
 
+    // allocate a h/w composer display id
+    int32_t allocateHwcDisplayId(DisplayDevice::DisplayType type);
+
     /* ------------------------------------------------------------------------
      * H/W composer
      */