Fix emulator vsync

The code that reserves display IDs was only run when a hardware
composer was present.  The eventControl() function, which handles
enabling of vsync, was ignoring the request because the primary
display didn't appear in its set of allocated IDs.  This moves
reservation of IDs for built-in displays outside the HWC-only block.

Also, added a couple of warnings in eventControl().

Bug 7376568

Change-Id: I185ccdf817a25499b5c2668f8f6d594afb8c1568

services/surfaceflinger/DisplayHardware/HWComposer.cpp

@@ -128,6 +128,11 @@ HWComposer::HWComposer(
         abort();
     }
 
+    // these display IDs are always reserved
+    for (size_t i=0 ; i<HWC_NUM_DISPLAY_TYPES ; i++) {
+        mAllocatedDisplayIDs.markBit(i);
+    }
+
     if (mHwc) {
         ALOGI("Using %s version %u.%u", HWC_HARDWARE_COMPOSER,
               (hwcApiVersion(mHwc) >> 24) & 0xff,
@@ -149,11 +154,6 @@ HWComposer::HWComposer(
         // always turn vsync off when we start
         eventControl(HWC_DISPLAY_PRIMARY, HWC_EVENT_VSYNC, 0);
 
-        // these IDs are always reserved
-        for (size_t i=0 ; i<HWC_NUM_DISPLAY_TYPES ; i++) {
-            mAllocatedDisplayIDs.markBit(i);
-        }
-
         // the number of displays we actually have depends on the
         // hw composer version
         if (hwcHasApiVersion(mHwc, HWC_DEVICE_API_VERSION_1_2)) {
@@ -445,6 +445,13 @@ bool HWComposer::isConnected(int disp) const {
 
 void HWComposer::eventControl(int disp, int event, int enabled) {
     if (uint32_t(disp)>31 || !mAllocatedDisplayIDs.hasBit(disp)) {
+        ALOGD("eventControl ignoring event %d on unallocated disp %d (en=%d)",
+              event, disp, enabled);
+        return;
+    }
+    if (event != EVENT_VSYNC) {
+        ALOGW("eventControl got unexpected event %d (disp=%d en=%d)",
+              event, disp, enabled);
         return;
     }
     status_t err = NO_ERROR;