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authorTomi Valkeinen <tomi.valkeinen@ideasonboard.com>2022-08-19 14:16:15 +0300
committerLaurent Pinchart <laurent.pinchart@ideasonboard.com>2022-08-19 15:44:28 +0300
commitbf3dbaece91e7f9be00923a225a62a918bf71f5b (patch)
treee22642e0d928e5827a781cea7d23743657b686b1 /src/py
parentde7f1aa591881e112b67ec4f6507a6079b226089 (diff)
py: Switch to non-blocking eventfd
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> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Diffstat (limited to 'src/py')
-rwxr-xr-xsrc/py/examples/simple-cam.py5
-rwxr-xr-xsrc/py/examples/simple-capture.py12
-rwxr-xr-xsrc/py/examples/simple-continuous-capture.py5
-rw-r--r--src/py/libcamera/py_camera_manager.cpp22
-rw-r--r--src/py/libcamera/py_camera_manager.h2
5 files changed, 34 insertions, 12 deletions
diff --git a/src/py/examples/simple-cam.py b/src/py/examples/simple-cam.py
index 2b81bb65..b3e97ca7 100755
--- a/src/py/examples/simple-cam.py
+++ b/src/py/examples/simple-cam.py
@@ -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()
diff --git a/src/py/examples/simple-capture.py b/src/py/examples/simple-capture.py
index a6a9b33e..5f93574f 100755
--- a/src/py/examples/simple-capture.py
+++ b/src/py/examples/simple-capture.py
@@ -14,6 +14,7 @@
import argparse
import libcamera as libcam
+import selectors
import sys
# Number of frames to capture
@@ -107,11 +108,18 @@ 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:
diff --git a/src/py/examples/simple-continuous-capture.py b/src/py/examples/simple-continuous-capture.py
index fe78a2dd..26a8060b 100755
--- a/src/py/examples/simple-continuous-capture.py
+++ b/src/py/examples/simple-continuous-capture.py
@@ -88,8 +88,9 @@ 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()
diff --git a/src/py/libcamera/py_camera_manager.cpp b/src/py/libcamera/py_camera_manager.cpp
index ea4ae825..9ccb7aad 100644
--- a/src/py/libcamera/py_camera_manager.cpp
+++ b/src/py/libcamera/py_camera_manager.cpp
@@ -24,7 +24,7 @@ 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");
@@ -62,7 +62,13 @@ py::list PyCameraManager::cameras()
std::vector<py::object> PyCameraManager::getReadyRequests()
{
- readFd();
+ int ret = readFd();
+
+ 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;
@@ -96,12 +102,18 @@ 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());
+ ssize_t ret = read(eventFd_.get(), buf, 8);
+
+ if (ret == 8)
+ return 0;
+ else if (ret < 0)
+ return -errno;
+ else
+ return -EIO;
}
void PyCameraManager::pushRequest(Request *req)
diff --git a/src/py/libcamera/py_camera_manager.h b/src/py/libcamera/py_camera_manager.h
index 56bea13d..3525057d 100644
--- a/src/py/libcamera/py_camera_manager.h
+++ b/src/py/libcamera/py_camera_manager.h
@@ -39,7 +39,7 @@ private:
LIBCAMERA_TSA_GUARDED_BY(completedRequestsMutex_);
void writeFd();
- void readFd();
+ int readFd();
void pushRequest(Request *req);
std::vector<Request *> getCompletedRequests();
};