New event handling

The current event handling relies on the PageFlipHandlerBase class which
has to be implemented on the python side.

This patch implements a more versatile event handling, where any python
object can be passed as data to the commit or page flip, and it's up to
the python implementation to decide what to do with that data when
receiving the event.

Note that when doing the commit or page_flip, the ref count of the
given python object is incremented to keep it alive. The ref count is
decremented when reading the events with the new helper method
card.read_events(). This helper _has_ to be used to ensure the objects
get released properly.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

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