1 files changed, 65 insertions, 0 deletions
diff --git a/py/pykms/__init__.py b/py/pykms/__init__.py
index d4cdc43..41c1219 100644
--- a/py/pykms/__init__.py
+++ b/py/pykms/__init__.py
@@ -1,4 +1,7 @@
 from .pykms import *
+from enum import Enum
+import os
+import struct
 
 #
 # Common RGB colours
@@ -58,3 +61,65 @@ def __card_disable_planes(self):
         print("disabling planes failed")
 
 Card.disable_planes = __card_disable_planes
+
+class DrmEventType(Enum):
+    VBLANK = 0x01
+    FLIP_COMPLETE = 0x02
+
+# struct drm_event {
+#   __u32 type;
+#   __u32 length;
+#};
+#
+
+_drm_ev = struct.Struct("II")
+
+#struct drm_event_vblank {
+#   struct drm_event base;
+#   __u64 user_data;
+#   __u32 tv_sec;
+#   __u32 tv_usec;
+#   __u32 sequence;
+#   __u32 reserved;
+#};
+
+_drm_ev_vbl = struct.Struct("QIIII") # Note: doesn't contain drm_event
+
+class DrmEvent:
+    def __init__(self, type, seq, time, data):
+        self.type = type
+        self.seq = seq
+        self.time = time
+        self.data = data
+
+# Return DrmEvents. Note: blocks if there's nothing to read
+def __card_read_events(self):
+    buf = os.read(self.fd, _drm_ev_vbl.size * 20)
+
+    if len(buf) == 0:
+        return
+
+    if len(buf) < _drm_ev.size:
+        raise RuntimeError("Partial DRM event")
+
+    idx = 0
+
+    while idx < len(buf):
+        ev_tuple = _drm_ev.unpack_from(buf, idx)
+
+        type = DrmEventType(ev_tuple[0])
+
+        if type != DrmEventType.VBLANK and type != DrmEventType.FLIP_COMPLETE:
+            raise RuntimeError("Illegal DRM event type")
+
+        vbl_tuple = _drm_ev_vbl.unpack_from(buf, idx + _drm_ev.size)
+
+        seq = vbl_tuple[3]
+        time = vbl_tuple[1] + vbl_tuple[2] / 1000000.0;
+        udata = pykms.__ob_unpack_helper(vbl_tuple[0])
+
+        yield DrmEvent(type, seq, time, udata)
+
+        idx += ev_tuple[1]
+
+Card.read_events = __card_read_events