The V4L2 compatibility layer uses devnum to match video device nodes to
libcamera Cameras. Some pipeline handlers don't report a devnum for
their camera, which prevents the V4L2 compatibility layer from matching
video device nodes to these cameras. To fix this, we first allow the
camera manager to map multiple devnums to a camera. Next, we walk the
media device and entity list and tell the camera manager to map every
one of these devnums that is a video capture node to the camera.
Since we decided that all video capture nodes that belong to a camera
can be opened via the V4L2 compatibility layer to map to that camera, it
would cause confusion for users if some pipeline handlers decided that
only specific device nodes would map to the camera. To prevent this
confusion, remove the ability for pipeline handlers to declare their own
devnum-to-camera mapping. The only pipeline handler that declares the
devnum mapping is the UVC pipeline handler, so remove the devnum there.
We considered walking the media entity list and taking the devnum from
just the one with the default flag set, but we found that some drivers
(eg. vimc) don't set this flag for any entity. Instead, we take all the
video capture nodes (entities with the sink pad flag set).
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
With the internal headers now in include/libcamera/internal/, we may
have identically named headers in include/libcamera/. Their header
guards would clash. Rename the header guards of internal headers to
prevent any issue.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
The libcamera internal headers are located in src/libcamera/include/.
The directory is added to the compiler headers search path with a meson
include_directories() directive, and internal headers are included with
(e.g. for the internal semaphore.h header)
#include "semaphore.h"
All was well, until libcxx decided to implement the C++20
synchronization library. The __threading_support header gained a
#include <semaphore.h>
to include the pthread's semaphore support. As include_directories()
adds src/libcamera/include/ to the compiler search path with -I, the
internal semaphore.h is included instead of the pthread version.
Needless to say, the compiler isn't happy.
Three options have been considered to fix this issue:
- Use -iquote instead of -I. The -iquote option instructs gcc to only
consider the header search path for headers included with the ""
version. Meson unfortunately doesn't support this option.
- Rename the internal semaphore.h header. This was deemed to be the
beginning of a long whack-a-mole game, where namespace clashes with
system libraries would appear over time (possibly dependent on
particular system configurations) and would need to be constantly
fixed.
- Move the internal headers to another directory to create a unique
namespace through path components. This causes lots of churn in all
the existing source files through the all project.
The first option would be best, but isn't available to us due to missing
support in meson. Even if -iquote support was added, we would need to
fix the problem before a new version of meson containing the required
support would be released.
The third option is thus the only practical solution available. Bite the
bullet, and do it, moving headers to include/libcamera/internal/.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Jacopo Mondi <jacopo@jmondi.org>
