@@ -19,8 +19,9 @@ TIMEOUT_SEC = 3
def handle_camera_event(cm):
- # cm.get_ready_requests() will not block here, as we know there is an event
- # to read.
+ # cm.get_ready_requests() returns the ready requests, which in our case
+ # should almost always return a single Request, but in some cases there
+ # could be multiple or none.
reqs = cm.get_ready_requests()
@@ -14,6 +14,7 @@
import argparse
import libcamera as libcam
+import selectors
import sys
# Number of frames to capture
@@ -102,11 +103,18 @@ def main():
# The main loop. Wait for the queued Requests to complete, process them,
# and re-queue them again.
+ sel = selectors.DefaultSelector()
+ sel.register(cm.event_fd, selectors.EVENT_READ)
+
while frames_done < TOTAL_FRAMES:
- # cm.get_ready_requests() blocks until there is an event and returns
- # all the ready requests. Here we should almost always get a single
+ # cm.get_ready_requests() does not block, so we use a Selector to wait
+ # for a camera event. Here we should almost always get a single
# Request, but in some cases there could be multiple or none.
+ events = sel.select()
+ if not events:
+ continue
+
reqs = cm.get_ready_requests()
for req in reqs:
@@ -83,8 +83,9 @@ class CaptureContext:
camera_contexts: list[CameraCaptureContext] = []
def handle_camera_event(self):
- # cm.get_ready_requests() will not block here, as we know there is an event
- # to read.
+ # cm.get_ready_requests() returns the ready requests, which in our case
+ # should almost always return a single Request, but in some cases there
+ # could be multiple or none.
reqs = self.cm.get_ready_requests()
@@ -22,7 +22,7 @@ PyCameraManager::PyCameraManager()
cameraManager_ = std::make_unique<CameraManager>();
- int fd = eventfd(0, EFD_CLOEXEC);
+ int fd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
if (fd == -1)
throw std::system_error(errno, std::generic_category(),
"Failed to create eventfd");
@@ -60,18 +60,24 @@ py::list PyCameraManager::cameras()
std::vector<py::object> PyCameraManager::getReadyRequests()
{
- readFd();
+ int ret = readFd();
- std::vector<py::object> ret;
+ if (ret == EAGAIN)
+ return std::vector<py::object>();
+
+ if (ret != 0)
+ throw std::system_error(ret, std::generic_category());
+
+ std::vector<py::object> py_reqs;
for (Request *request : getCompletedRequests()) {
py::object o = py::cast(request);
/* Decrease the ref increased in Camera.queue_request() */
o.dec_ref();
- ret.push_back(o);
+ py_reqs.push_back(o);
}
- return ret;
+ return py_reqs;
}
/* Note: Called from another thread */
@@ -94,12 +100,14 @@ void PyCameraManager::writeFd()
LOG(Python, Fatal) << "Unable to write to eventfd";
}
-void PyCameraManager::readFd()
+int PyCameraManager::readFd()
{
uint8_t buf[8];
if (read(eventFd_.get(), buf, 8) != 8)
- throw std::system_error(errno, std::generic_category());
+ return errno;
+
+ return 0;
}
void PyCameraManager::pushRequest(Request *req)
@@ -39,7 +39,7 @@ private:
LIBCAMERA_TSA_GUARDED_BY(completedRequestsMutex_);
void writeFd();
- void readFd();
+ int readFd();
void pushRequest(Request *req);
std::vector<Request *> getCompletedRequests();
};
@@ -191,9 +191,16 @@ class SimpleCaptureMethods(CameraTesterBase):
reqs = None
gc.collect()
+ sel = selectors.DefaultSelector()
+ sel.register(cm.event_fd, selectors.EVENT_READ)
+
reqs = []
while True:
+ events = sel.select()
+ if not events:
+ continue
+
ready_reqs = cm.get_ready_requests()
reqs += ready_reqs
Blocking wait can be easily implemented on top in Python, so rather than supporting only blocking reads, or supporting both non-blocking and blocking reads, let's support only non-blocking reads. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> --- src/py/examples/simple-cam.py | 5 +++-- src/py/examples/simple-capture.py | 12 +++++++++-- src/py/examples/simple-continuous-capture.py | 5 +++-- src/py/libcamera/py_camera_manager.cpp | 22 +++++++++++++------- src/py/libcamera/py_camera_manager.h | 2 +- test/py/unittests.py | 7 +++++++ 6 files changed, 39 insertions(+), 14 deletions(-)