Hi Hans,
Am Sonntag, den 26.07.2015, 13:18 +0200 schrieb Hans Verkuil:
> Hi Philipp,
[...]
> > diff --git a/drivers/media/v4l2-core/videobuf2-core.c
> > b/drivers/media/v4l2-core/videobuf2-core.c
> > index 93b3154..b866a6b 100644
> > --- a/drivers/media/v4l2-core/videobuf2-core.c
> > +++ b/drivers/media/v4l2-core/videobuf2-core.c
> > @@ -30,6 +30,8 @@
> > #include <media/v4l2-common.h>
> > #include <media/videobuf2-core.h>
> >
>
> Shouldn't there be a #define CREATE_TRACE_POINTS added before the include?
> That's
> what is done in v4l2-ioctl.c as well.
Documentation/trace/tracepoints.txt says
"if you use the header in multiple source files,
#define CREATE_TRACE_POINTS should appear only in one source file."
> I updated my kernel on my laptop to the latest media master and without this
> line it
> gives me link errors:
>
> ERROR: "__tracepoint_vb2_qbuf" [drivers/media/v4l2-core/videobuf2-core.ko]
> undefined!
> ERROR: "__tracepoint_vb2_buf_done"
> [drivers/media/v4l2-core/videobuf2-core.ko] undefined!
> ERROR: "__tracepoint_vb2_buf_queue"
> [drivers/media/v4l2-core/videobuf2-core.ko] undefined!
> ERROR: "__tracepoint_vb2_dqbuf" [drivers/media/v4l2-core/videobuf2-core.ko]
> undefined!
> scripts/Makefile.modpost:90: recipe for target '__modpost' failed
Since drivers/media/v4l2-core/v4l2-ioctl.c is built with the trace
points whenever CONFIG_VIDEO_V4L2 is enabled, the symbols will currently
end up in drivers/media/v4l2-core/v4l2-ioctl.o, but they are not
exported.
> I'm not sure why I didn't see this anywhere else, but can you take a look at
> this?
I didn't notice because I hadn't built kernels with VIDEO_V4L2 and
VIDEOBUF2_CORE as modules on x86. I'm not sure why I don't get these
errors on ARM, but I suppose this issue is a reason to split the vb2
tracepoints out of include/trace/event/v4l2.h into their own header
anyway. The vb2 tracepoint implementation should reside in the
videobuf2-core module.
regards
Philipp
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