gralloc: Do not map framebuffer memory unless needed

The SurfaceFlinger opens the framebuffer module even when it
isn't necessary. It does this for some legacy hals.
Due to this we unnecessarily mmap the fb memory in gralloc.
Do not map this unless the property to use the framebuffer
memory is set.

Change-Id: Ib4ebfdf9a63af0dabb53170342181bac0360baeb

1 files changed, 9 insertions, 3 deletions

diff --git a/libgralloc/framebuffer.cpp b/libgralloc/framebuffer.cpp
index 382868009..185119686 100644
--- a/libgralloc/framebuffer.cpp
+++ b/libgralloc/framebuffer.cpp
@@ -336,9 +336,15 @@ int mapFrameBufferLocked(struct private_module_t* module)
 
 static int mapFrameBuffer(struct private_module_t* module)
 {
-    pthread_mutex_lock(&module->lock);
-    int err = mapFrameBufferLocked(module);
-    pthread_mutex_unlock(&module->lock);
+    int err = 0;
+    char property[PROPERTY_VALUE_MAX];
+    if((property_get("debug.gralloc.map_fb_memory", property, NULL) > 0) &&
+       (!strncmp(property, "1", PROPERTY_VALUE_MAX ) ||
+        (!strncasecmp(property,"true", PROPERTY_VALUE_MAX )))) {
+        pthread_mutex_lock(&module->lock);
+        err = mapFrameBufferLocked(module);
+        pthread_mutex_unlock(&module->lock);
+    }
     return err;
 }