Patch from upstream bug tracker:
https://sourceforge.net/tracker/?func=detail&aid=3336448&group_id=167869&atid=844658

As only part of G510 support was merged to upstream. Does NOT apply & compile
on top of 1.2.7-r1.

diff -aNru trunk/libg15/libg15.c mod/libg15/libg15.c
--- trunk/libg15/libg15.c	2011-03-31 23:33:44.000000000 +0000
+++ mod/libg15/libg15.c	2011-06-26 07:08:21.000000000 +0000
@@ -1029,6 +1029,76 @@
 	}
 }
 
+// Logitech G510 Media Keys implementation. Unknown if this will work for other
+// models. Using the backlight key as a modifier. The assumption is you would
+// normally not be holding down the backlight key while pressing G-keys.
+static void processKeyEvent2Byte(unsigned int *pressed_keys, unsigned char *buffer)
+{
+    // Key modifier
+    *pressed_keys |= G15_KEY_LIGHT;
+
+    // XF86AudioPlay
+    if (*pressed_keys & G15_KEY_G1)
+	     *pressed_keys -= G15_KEY_G1;
+
+    // XF86AudioStop
+    if (*pressed_keys & G15_KEY_G2)
+	     *pressed_keys -= G15_KEY_G2;
+
+    // XF86AudioPrev
+    if (*pressed_keys & G15_KEY_G3)
+	     *pressed_keys -= G15_KEY_G3;
+
+    // XF86AudioNext
+    if (*pressed_keys & G15_KEY_G4)
+	     *pressed_keys -= G15_KEY_G4;
+
+    // XF86AudioMute
+    if (*pressed_keys & G15_KEY_G5)
+	     *pressed_keys -= G15_KEY_G5;
+
+    // XF86AudioRaiseVolume
+    if (*pressed_keys & G15_KEY_G6)
+	     *pressed_keys -= G15_KEY_G6;
+
+    // XF86AudioLowerVolume
+    if (*pressed_keys & G15_KEY_G7)
+	     *pressed_keys -= G15_KEY_G7;
+
+    g15_log(stderr,G15_LOG_WARN,"Keyboard: %x, %x\n", buffer[0], buffer[1]);
+
+    if (buffer[0] == 0x02)
+    {
+        // XF86AudioPlay
+        if (buffer[1] & 0x08)
+            *pressed_keys |= G15_KEY_G1;
+
+        // XF86AudioStop
+        if (buffer[1] & 0x04)
+            *pressed_keys |= G15_KEY_G2;
+
+        // XF86AudioPrev
+        if (buffer[1] & 0x02)
+            *pressed_keys |= G15_KEY_G3;
+
+        // XF86AudioNext
+        if (buffer[1] & 0x01)
+            *pressed_keys |= G15_KEY_G4;
+
+        // XF86AudioMute
+        if (buffer[1] & 0x16)
+            *pressed_keys |= G15_KEY_G5;
+
+        // XF86AudioRaiseVolume
+        if (buffer[1] & 0x32)
+            *pressed_keys |= G15_KEY_G6;
+
+        // XF86AudioLowerVolume
+        if (buffer[1] & 0x64)
+            *pressed_keys |= G15_KEY_G7;
+    }
+}
+
 int getPressedKeys(unsigned int *pressed_keys, unsigned int timeout)
 {
     unsigned char buffer[G15_KEY_READ_LENGTH];
@@ -1063,6 +1133,13 @@
       case 9:
           processKeyEvent9Byte(pressed_keys, buffer);
           return G15_NO_ERROR;
+      case 2:
+          if (g15DeviceCapabilities() & G15_DEVICE_G510)
+			 {
+              processKeyEvent2Byte(pressed_keys, buffer);
+              return G15_NO_ERROR;
+		    }
+			 // Deliberate fallthrough
       default:
           return handle_usb_errors("Keyboard Read", ret); /* allow the app to deal with errors */
     }