AML Windowing: add DRM vsync

Reduce CPU load when nothing is rendered.

Author: Portisch

xbmc/windowing/amlogic/AMLDisplay.cpp

@@ -376,6 +376,17 @@ void CAMLDRMUtils::aml_set_framebuffer_resolution(unsigned int width,
   }
 }
 
+void CAMLDRMUtils::aml_drmDevice_vsync()
+{
+  if (m_fd != -1)
+  {
+    drmVBlank vbl = {};
+    vbl.request.type = DRM_VBLANK_RELATIVE;
+    vbl.request.sequence = 1;
+    drmWaitVBlank(m_fd, &vbl);
+  }
+}
+
 // get drmDevice
 int CAMLDRMUtils::aml_get_drmDevice()
 {

xbmc/windowing/amlogic/AMLDisplay.h

@@ -50,6 +50,7 @@ class CAMLDRMUtils
 
   int aml_get_drmDevice_handle() const { return m_fd; }
   void aml_init_drmDevice();
+  void aml_drmDevice_vsync();
   std::string aml_get_drmDevice_mode();
   std::string aml_get_drmDevice_modes();
   bool aml_set_drmDevice_mode(const RESOLUTION_INFO &res, std::string mode,
@@ -104,6 +105,7 @@ class CAMLDisplay
 
   int aml_get_Device_handle() const { return m_amlDRMUtils->aml_get_drmDevice_handle(); }
   void aml_init_drmDevice() { m_amlDRMUtils->aml_init_drmDevice(); }
+  void aml_drmDevice_vsync() { m_amlDRMUtils->aml_drmDevice_vsync(); };
   bool aml_get_display_connected() const { return m_amlDRMUtils->aml_get_drmDevice_connected(); }
   bool set_native_resolution(const RESOLUTION_INFO &res, std::string framebuffer_name,
     const int stereo_mode, bool force_mode_switch);

xbmc/windowing/amlogic/WinSystemAmlogicGLESContext.cpp

@@ -306,6 +306,10 @@ void CWinSystemAmlogicGLESContext::PresentRender(bool rendered, bool videoLayer)
         (*i)->OnResetDisplay();
     }
   }
+  else if (!rendered && !videoLayer)
+  {
+    m_amlDisplay->aml_drmDevice_vsync();
+  }
 }
 
 EGLDisplay CWinSystemAmlogicGLESContext::GetEGLDisplay() const