Here is the system log, in case that helps:
Lakka:~ # systemctl stop retroarch.service ; retroarch -v
RetroArch [INFO] :: === Build =======================================
Capabilities: MMX MMXEXT SSE1 SSE2 SSE3 SSSE3 SSE4 SSE4.2
Built: Sep 27 2016
RetroArch [INFO] :: Version: 1.3.6
RetroArch [INFO] :: Git: 03241bf
RetroArch [INFO] :: =================================================
RetroArch [INFO] :: Looking for config in: “/storage/.config/retroarch/retroarch.cfg”.
RetroArch [INFO] :: Config: loading config from: /storage/.config/retroarch/retroarch.cfg.
RetroArch [INFO] :: Resetting undo buffers.
RetroArch [INFO] :: Environ SET_PIXEL_FORMAT: RGB565.
RetroArch [INFO] :: Version of libretro API: 1
RetroArch [INFO] :: Compiled against API: 1
RetroArch [INFO] :: Set audio input rate to: 29970.03 Hz.
RetroArch [INFO] :: Found shader “/usr/share/common-shaders/bilinear.glslp”
RetroArch [INFO] :: Found shader “/usr/share/common-shaders/nearest.glslp”
RetroArch [INFO] :: Found shader “/usr/share/common-shaders/stock.glsl”
RetroArch [INFO] :: Video @ 960x720
RetroArch [INFO] :: Starting threaded video driver …
RetroArch [INFO] :: [DRM]: Found 3 connectors.
RetroArch [INFO] :: [DRM]: Connector 0 connected: no
RetroArch [INFO] :: [DRM]: Connector 0 has 0 modes.
RetroArch [INFO] :: [DRM]: Connector 1 connected: yes
RetroArch [INFO] :: [DRM]: Connector 1 has 48 modes.
RetroArch [INFO] :: [DRM]: Connector 1 assigned to monitor index: #1.
RetroArch [INFO] :: [DRM]: Connector 2 connected: no
RetroArch [INFO] :: [DRM]: Connector 2 has 0 modes.
RetroArch [INFO] :: [DRM]: Mode 0: (3840x2160) 3840 x 2160, 30 Hz
RetroArch [INFO] :: [DRM]: Mode 1: (4096x2160) 4096 x 2160, 24 Hz
RetroArch [INFO] :: [DRM]: Mode 2: (4096x2160) 4096 x 2160, 24 Hz
RetroArch [INFO] :: [DRM]: Mode 3: (3840x2160) 3840 x 2160, 30 Hz
RetroArch [INFO] :: [DRM]: Mode 4: (3840x2160) 3840 x 2160, 25 Hz
RetroArch [INFO] :: [DRM]: Mode 5: (3840x2160) 3840 x 2160, 24 Hz
RetroArch [INFO] :: [DRM]: Mode 6: (3840x2160) 3840 x 2160, 24 Hz
RetroArch [INFO] :: [DRM]: Mode 7: (1920x1080) 1920 x 1080, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 8: (1920x1080) 1920 x 1080, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 9: (1920x1080i) 1920 x 1080, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 10: (1920x1080i) 1920 x 1080, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 11: (1920x1080) 1920 x 1080, 50 Hz
RetroArch [INFO] :: [DRM]: Mode 12: (1920x1080i) 1920 x 1080, 50 Hz
RetroArch [INFO] :: [DRM]: Mode 13: (1920x1080) 1920 x 1080, 30 Hz
RetroArch [INFO] :: [DRM]: Mode 14: (1920x1080) 1920 x 1080, 30 Hz
RetroArch [INFO] :: [DRM]: Mode 15: (1920x1080) 1920 x 1080, 25 Hz
RetroArch [INFO] :: [DRM]: Mode 16: (1920x1080) 1920 x 1080, 24 Hz
RetroArch [INFO] :: [DRM]: Mode 17: (1920x1080) 1920 x 1080, 24 Hz
RetroArch [INFO] :: [DRM]: Mode 18: (1680x1050) 1680 x 1050, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 19: (1600x900) 1600 x 900, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 20: (1280x1024) 1280 x 1024, 75 Hz
RetroArch [INFO] :: [DRM]: Mode 21: (1280x1024) 1280 x 1024, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 22: (1440x900) 1440 x 900, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 23: (1366x768) 1366 x 768, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 24: (1280x800) 1280 x 800, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 25: (1152x864) 1152 x 864, 75 Hz
RetroArch [INFO] :: [DRM]: Mode 26: (1280x720) 1280 x 720, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 27: (1280x720) 1280 x 720, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 28: (1280x720) 1280 x 720, 50 Hz
RetroArch [INFO] :: [DRM]: Mode 29: (1024x768) 1024 x 768, 75 Hz
RetroArch [INFO] :: [DRM]: Mode 30: (1024x768) 1024 x 768, 70 Hz
RetroArch [INFO] :: [DRM]: Mode 31: (1024x768) 1024 x 768, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 32: (832x624) 832 x 624, 75 Hz
RetroArch [INFO] :: [DRM]: Mode 33: (800x600) 800 x 600, 75 Hz
RetroArch [INFO] :: [DRM]: Mode 34: (800x600) 800 x 600, 72 Hz
RetroArch [INFO] :: [DRM]: Mode 35: (800x600) 800 x 600, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 36: (720x576) 720 x 576, 50 Hz
RetroArch [INFO] :: [DRM]: Mode 37: (720x576i) 720 x 576, 50 Hz
RetroArch [INFO] :: [DRM]: Mode 38: (720x480) 720 x 480, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 39: (720x480) 720 x 480, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 40: (720x480i) 720 x 480, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 41: (720x480i) 720 x 480, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 42: (640x480) 640 x 480, 75 Hz
RetroArch [INFO] :: [DRM]: Mode 43: (640x480) 640 x 480, 73 Hz
RetroArch [INFO] :: [DRM]: Mode 44: (640x480) 640 x 480, 67 Hz
RetroArch [INFO] :: [DRM]: Mode 45: (640x480) 640 x 480, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 46: (640x480) 640 x 480, 60 Hz
RetroArch [INFO] :: [DRM]: Mode 47: (720x400) 720 x 400, 70 Hz
RetroArch [INFO] :: Found GL context: kms
RetroArch [INFO] :: Detecting screen resolution 3840x2160.
RetroArch [INFO] :: [EGL]: EGL version: 1.4
RetroArch [INFO] :: [EGL]: Current context: 0x7f3ae8121ca0.
RetroArch [INFO] :: [KMS]: New FB: 3840x2160 (stride: 15360).
RetroArch [INFO] :: [GL]: Vendor: Intel Open Source Technology Center, Renderer: Mesa DRI Intel® Haswell Desktop .
RetroArch [INFO] :: [GL]: Version: 3.0 Mesa 11.2.0-rc1.
RetroArch [INFO] :: GL: Using resolution 3840x2160
RetroArch [INFO] :: [GL]: Default shader backend found: glsl.
RetroArch [INFO] :: [Shader driver]: Using GLSL shader backend.
RetroArch [INFO] :: Checking GLSL shader support …
RetroArch [WARN] :: [GL]: Stock GLSL shaders will be used.
RetroArch [INFO] :: Found GLSL vertex shader.
RetroArch [INFO] :: Found GLSL fragment shader.
RetroArch [INFO] :: Linking GLSL program.
RetroArch [INFO] :: Found GLSL vertex shader.
RetroArch [INFO] :: Found GLSL fragment shader.
RetroArch [INFO] :: Linking GLSL program.
RetroArch [INFO] :: Found GLSL vertex shader.
RetroArch [INFO] :: Found GLSL fragment shader.
RetroArch [INFO] :: Linking GLSL program.
RetroArch [INFO] :: Found GLSL vertex shader.
RetroArch [INFO] :: Found GLSL fragment shader.
RetroArch [INFO] :: Linking GLSL program.
RetroArch [INFO] :: Found GLSL vertex shader.
RetroArch [INFO] :: Found GLSL fragment shader.
RetroArch [INFO] :: Linking GLSL program.
RetroArch [INFO] :: [GL]: Using 4 textures.
RetroArch [INFO] :: [GL]: Loaded 1 program(s).
RetroArch [INFO] :: [GL]: Using GL_RGB565 for texture uploads.
RetroArch [INFO] :: Using font rendering backend: freetype.
RetroArch [INFO] :: Graphics driver did not initialize an input driver. Attempting to pick a suitable driver.
RetroArch [WARN] :: [udev]: Couldn’t open any keyboard, mouse or touchpad. Are permissions set correctly for /dev/input/event*?
RetroArch [INFO] :: Found joypad driver: “udev”.
RetroArch [INFO] :: ALSA: Using signed 16-bit format.
RetroArch [INFO] :: ALSA: Period size: 384 frames
RetroArch [INFO] :: ALSA: Buffer size: 1536 frames
RetroArch [INFO] :: Found menu display driver: “menu_display_gl”.
RetroArch [INFO] :: Using font rendering backend: freetype.
RetroArch [INFO] :: Using font rendering backend: freetype.
RetroArch [INFO] :: SRAM will not be saved.
RetroArch [INFO] :: Loading history file: [/storage/.config/retroarch/content_history.lpl].
RetroArch [INFO] :: Loading history file: [/storage/.config/retroarch/content_music_history.lpl].
RetroArch [INFO] :: Loading history file: [/storage/.config/retroarch/content_video_history.lpl].
RetroArch [INFO] :: Loading history file: [/storage/.config/retroarch/content_image_history.lpl].
RetroArch [INFO] :: [KMS]: New FB: 3840x2160 (stride: 15360).
RetroArch [INFO] :: [KMS]: New FB: 3840x2160 (stride: 15360).