Hello Hans I am implementing a test application for our camera, think of v4l2-compliance but for testing the hardware (average of pixels, rotation...) . I am implementing it using python (because of numpy and matplotlib). I dont really care about perferomance, I only care about the data correctness, so the fileio fits perfectly my needs. On the fileio api we dont have a way to tell the camera to stop, this was an attempt to solve this "issue". But if it is only an issue for me we can forget about it :). BTW, do you know about a complete v4l2 library for python? I am using https://pypi.python.org/pypi/v4l2 , but it is quite old. Thanks! On Fri, Oct 4, 2013 at 4:09 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > Hi Ricardo, > > On 10/04/2013 03:49 PM, Ricardo Ribalda Delgado wrote: >> A video device opened and streaming in io emulator mode can only stop >> streamming if its file descriptor is closed. >> >> There are some parameters that can only be changed if the device is not >> streaming. Also, the power consumption of a device streaming could be >> different than one not streaming. >> >> With this patch a video device opened in io emulator can be stopped on >> demand. > > Why would you want this? If you can call STREAMOFF, why not use stream I/O > all the way? That's much more efficient than read() anyway. > > Unless there is a very good use-case, I don't see a good reason for mixing > file I/O with streaming I/O ioctls. > > Regards, > > Hans > >> >> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx> >> --- >> drivers/media/v4l2-core/videobuf2-core.c | 11 ++++++----- >> 1 file changed, 6 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c >> index 9fc4bab..097fba8 100644 >> --- a/drivers/media/v4l2-core/videobuf2-core.c >> +++ b/drivers/media/v4l2-core/videobuf2-core.c >> @@ -1686,6 +1686,7 @@ int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type) >> } >> EXPORT_SYMBOL_GPL(vb2_streamon); >> >> +static int __vb2_cleanup_fileio(struct vb2_queue *q); >> >> /** >> * vb2_streamoff - stop streaming >> @@ -1704,11 +1705,6 @@ EXPORT_SYMBOL_GPL(vb2_streamon); >> */ >> int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type) >> { >> - if (q->fileio) { >> - dprintk(1, "streamoff: file io in progress\n"); >> - return -EBUSY; >> - } >> - >> if (type != q->type) { >> dprintk(1, "streamoff: invalid stream type\n"); >> return -EINVAL; >> @@ -1719,6 +1715,11 @@ int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type) >> return -EINVAL; >> } >> >> + if (q->fileio) { >> + __vb2_cleanup_fileio(q); >> + return 0; >> + } >> + >> /* >> * Cancel will pause streaming and remove all buffers from the driver >> * and videobuf, effectively returning control over them to userspace. >> > -- Ricardo Ribalda -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
