[libcamera-devel] [PATCH v3 09/13] android: camera_device: Query plane length

[Kieran Bingham]

Use lseek to query the length of planes where possible rather than leaving
the plane.length as zero, which prevents mapping buffers for software
processing.

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

---
v3
 - Return nullptr if we fail to query plane length

v2:
 - no longer support an invalid plane length.
---
 src/android/camera_device.cpp | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index 087e226f5a82..5899154b3e78 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -1096,12 +1096,13 @@ FrameBuffer *CameraDevice::createFrameBuffer(const buffer_handle_t camera3buffer
 			break;
 		}
 
-		/*
-		 * Setting length to zero here is OK as the length is only used
-		 * to map the memory of the plane. Libcamera do not need to poke
-		 * at the memory content queued by the HAL.
-		 */
-		plane.length = 0;
+		off_t length = lseek(plane.fd.fd(), 0, SEEK_END);
+		if (length == -1) {
+			LOG(HAL, Error) << "Failed to query plane length";
+			return nullptr;
+		}
+
+		plane.length = length;
 		planes.push_back(std::move(plane));
 	}
 
-- 
2.25.1