[libcamera-devel] [PATCH] android: Re-order out-of-order completion path

[Jacopo Mondi]

When the camera HAL detects an out-of-order completion of a request, it
sends to the camera framework a CAMERA3_MSG_ERROR_DEVICE error.

Such error not only forces the service to close the camera as prescribed
by the camera3 specification, but in some implementation (specifically
the ChromeOS one) it causes the camera service to abort and exit.

This prevents any error messages to be printed by libcamera, as the
library gets terminated before getting to that point, and also hides the
printout of error messages that lead to out-of-order completion, making
it impossible to get from the output log what happened.

Move the call to notifyError() at the end of the error path and demote
the error message to LogLevels::Error from Fatal to let the service
implementation decide how to handle CAMERA3_MSG_ERROR_DEVICE errors.

Before this patch, when waiting on a fence fails and the capture
request is not queued to the Camera, we get an out-of-order completion
but no backtrace. With this patch applied the error path is visible:

ERROR HAL camera_worker.cpp:122 Failed waiting for fence: 82: Timer expired
ERROR HAL camera_device.cpp:1110 '\_SB_.PCI0.I2C2.CAM0': Out-of-order completion for request 0x00007e6de4004c70

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/android/camera_device.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index 901867105085..f60297e13c8b 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -1104,16 +1104,17 @@ void CameraDevice::requestComplete(Request *request)
 	if (descriptor->request_->cookie() != request->cookie()) {
 		/*
 		 * \todo Clarify if the Camera has to be closed on
-		 * ERROR_DEVICE and possibly demote the Fatal to simple
-		 * Error.
+		 * ERROR_DEVICE.
 		 */
-		notifyError(0, nullptr, CAMERA3_MSG_ERROR_DEVICE);
-		LOG(HAL, Fatal)
+		LOG(HAL, Error)
 			<< "Out-of-order completion for request "
 			<< utils::hex(request->cookie());
 
 		MutexLocker descriptorsLock(descriptorsMutex_);
 		descriptors_.pop();
+
+		notifyError(0, nullptr, CAMERA3_MSG_ERROR_DEVICE);
+
 		return;
 	}
 
-- 
2.33.0