On Wednesday 10 February 2010 15:58:04 Sakari Ailus wrote: > This patch adds a set of new ioctls to the V4L2 API. The ioctls conform to > V4L2 Events RFC version 2.3: I've experimented with the events API to try and support it with ivtv and I realized that it had some problems. See comments below. > > <URL:http://www.spinics.net/lists/linux-media/msg12033.html> > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxxxxxxxxxxxxx> > --- > drivers/media/video/v4l2-compat-ioctl32.c | 3 +++ > drivers/media/video/v4l2-ioctl.c | 3 +++ > include/linux/videodev2.h | 23 +++++++++++++++++++++++ > 3 files changed, 29 insertions(+), 0 deletions(-) > > diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c > index 997975d..cba704c 100644 > --- a/drivers/media/video/v4l2-compat-ioctl32.c > +++ b/drivers/media/video/v4l2-compat-ioctl32.c > @@ -1077,6 +1077,9 @@ long v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg) > case VIDIOC_DBG_G_REGISTER: > case VIDIOC_DBG_G_CHIP_IDENT: > case VIDIOC_S_HW_FREQ_SEEK: > + case VIDIOC_DQEVENT: > + case VIDIOC_SUBSCRIBE_EVENT: > + case VIDIOC_UNSUBSCRIBE_EVENT: > ret = do_video_ioctl(file, cmd, arg); > break; > > diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c > index 30cc334..bfc4696 100644 > --- a/drivers/media/video/v4l2-ioctl.c > +++ b/drivers/media/video/v4l2-ioctl.c > @@ -283,6 +283,9 @@ static const char *v4l2_ioctls[] = { > > [_IOC_NR(VIDIOC_DBG_G_CHIP_IDENT)] = "VIDIOC_DBG_G_CHIP_IDENT", > [_IOC_NR(VIDIOC_S_HW_FREQ_SEEK)] = "VIDIOC_S_HW_FREQ_SEEK", > + [_IOC_NR(VIDIOC_DQEVENT)] = "VIDIOC_DQEVENT", > + [_IOC_NR(VIDIOC_SUBSCRIBE_EVENT)] = "VIDIOC_SUBSCRIBE_EVENT", > + [_IOC_NR(VIDIOC_UNSUBSCRIBE_EVENT)] = "VIDIOC_UNSUBSCRIBE_EVENT", > #endif > }; > #define V4L2_IOCTLS ARRAY_SIZE(v4l2_ioctls) > diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h > index 54af357..a19ae89 100644 > --- a/include/linux/videodev2.h > +++ b/include/linux/videodev2.h > @@ -1536,6 +1536,26 @@ struct v4l2_streamparm { > }; > > /* > + * E V E N T S > + */ > + > +struct v4l2_event { > + __u32 count; The name 'count' is confusing. Count of what? I think the name 'pending' might be more understandable. A comment after the definition would also help. > + __u32 type; > + __u32 sequence; > + struct timespec timestamp; > + __u32 reserved[9]; > + __u8 data[64]; > +}; I also think we should reorder the fields and add a union. For ivtv I would need this: #define V4L2_EVENT_ALL 0 #define V4L2_EVENT_VSYNC 1 #define V4L2_EVENT_EOS 2 #define V4L2_EVENT_PRIVATE_START 0x08000000 /* Payload for V4L2_EVENT_VSYNC */ struct v4l2_event_vsync { /* Can be V4L2_FIELD_ANY, _NONE, _TOP or _BOTTOM */ u8 field; } __attribute__ ((packed)); struct v4l2_event { __u32 type; union { struct v4l2_event_vsync vsync; __u8 data[64]; } u; __u32 sequence; struct timespec timestamp; __u32 pending; __u32 reserved[9]; }; The reason for rearranging the fields has to do with the fact that the first two fields (type and the union) form the actual event data. The others are more for administrative purposes. Separating those two makes sense to me. So when I define an event for queuing it is nice if I can do just this: static const struct v4l2_event ev_top = { .type = V4L2_EVENT_VSYNC, .u.vsync.field = V4L2_FIELD_TOP, }; I would have preferred to have an anonymous union. Unfortunately gcc has problems with initializers for fields inside an anonymous union. Hence the need for a named union. Regards, Hans > + > +struct v4l2_event_subscription { > + __u32 type; > + __u32 reserved[7]; > +}; > + > +#define V4L2_EVENT_PRIVATE_START 0x08000000 > + > +/* > * A D V A N C E D D E B U G G I N G > * > * NOTE: EXPERIMENTAL API, NEVER RELY ON THIS IN APPLICATIONS! > @@ -1651,6 +1671,9 @@ struct v4l2_dbg_chip_ident { > #endif > > #define VIDIOC_S_HW_FREQ_SEEK _IOW('V', 82, struct v4l2_hw_freq_seek) > +#define VIDIOC_DQEVENT _IOR('V', 83, struct v4l2_event) > +#define VIDIOC_SUBSCRIBE_EVENT _IOW('V', 84, struct v4l2_event_subscription) > +#define VIDIOC_UNSUBSCRIBE_EVENT _IOW('V', 85, struct v4l2_event_subscription) > /* Reminder: when adding new ioctls please add support for them to > drivers/media/video/v4l2-compat-ioctl32.c as well! */ > > -- Hans Verkuil - video4linux developer - sponsored by TANDBERG -- 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
