On 05/09/2014 03:09 PM, Laurent Pinchart wrote:
> Hi Arun,
>
> Thank you for the patch. We're slowly getting there :-)
>
> On Thursday 08 May 2014 17:19:15 Arun Kumar K wrote:
>> This event indicates that the video device has encountered
>> a source parameter change during runtime. This can typically be a
>> resolution change detected by a video decoder OR a format change
>> detected by an HDMI connector.
>>
>> This needs to be nofified to the userspace and the application may
>> be expected to reallocate buffers before proceeding. The application
>> can subscribe to events on a specific pad or input/output port which
>> it is interested in.
>>
>> Signed-off-by: Arun Kumar K <arun...@samsung.com>
>> ---
>> Documentation/DocBook/media/v4l/vidioc-dqevent.xml | 32 +++++++++++++++++
>> .../DocBook/media/v4l/vidioc-subscribe-event.xml | 19 +++++++++++
>> drivers/media/v4l2-core/v4l2-event.c | 36 +++++++++++++++++
>> include/media/v4l2-event.h | 4 +++
>> include/uapi/linux/videodev2.h | 8 +++++
>> 5 files changed, 99 insertions(+)
>>
>> diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml
>> b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml index 89891ad..6afabaa
>> 100644
>> --- a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml
>> +++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml
>> @@ -242,6 +242,22 @@
>> </tgroup>
>> </table>
>>
>> + <table frame="none" pgwide="1" id="v4l2-event-src-change">
>> + <title>struct <structname>v4l2_event_src_change</structname></title>
>> + <tgroup cols="3">
>> + &cs-str;
>> + <tbody valign="top">
>> + <row>
>> + <entry>__u32</entry>
>> + <entry><structfield>changes</structfield></entry>
>> + <entry>
>> + A bitmask that tells what has changed. See <xref
>> linkend="src-changes-flags" />. + </entry>
>> + </row>
>> + </tbody>
>> + </tgroup>
>> + </table>
>> +
>> <table pgwide="1" frame="none" id="changes-flags">
>> <title>Changes</title>
>> <tgroup cols="3">
>> @@ -270,6 +286,22 @@
>> </tbody>
>> </tgroup>
>> </table>
>> +
>> + <table pgwide="1" frame="none" id="src-changes-flags">
>> + <title>Source Changes</title>
>> + <tgroup cols="3">
>> + &cs-def;
>> + <tbody valign="top">
>> + <row>
>> + <entry><constant>V4L2_EVENT_SRC_CH_RESOLUTION</constant></entry>
>> + <entry>0x0001</entry>
>> + <entry>This event gets triggered when a resolution change is
>> + detected at runtime. This can typically come from a video decoder.
>> + </entry>
>> + </row>
>> + </tbody>
>> + </tgroup>
>> + </table>
>> </refsect1>
>> <refsect1>
>> &return-value;
>> diff --git a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml
>> b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml index
>> 5c70b61..8012829 100644
>> --- a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml
>> +++ b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml
>> @@ -155,6 +155,25 @@
>> </entry>
>> </row>
>> <row>
>> + <entry><constant>V4L2_EVENT_SOURCE_CHANGE</constant></entry>
>> + <entry>5</entry>
>> + <entry>
>> + <para>This event is triggered when a format change is
>> + detected during runtime by the video device. It can be a
>> + runtime resolution change triggered by a video decoder or the
>> + format change happening on an HDMI connector.
>> + This event requires that the <structfield>id</structfield>
>> + matches the pad/input/output index from which you want to
>> + receive events.</para>
>> +
>> + <para>This event has a &v4l2-event-source-change; associated
>> + with it. The <structfield>changes</structfield> bitfield denotes
>> + what has changed for the subscribed pad. If multiple events
>> + occured before application could dequeue them, then the changes
>> + will have the ORed value of all the events generated.</para>
>> + </entry>
>> + </row>
>> + <row>
>> <entry><constant>V4L2_EVENT_PRIVATE_START</constant></entry>
>> <entry>0x08000000</entry>
>> <entry>Base event number for driver-private events.</entry>
>> diff --git a/drivers/media/v4l2-core/v4l2-event.c
>> b/drivers/media/v4l2-core/v4l2-event.c index 86dcb54..8761aab 100644
>> --- a/drivers/media/v4l2-core/v4l2-event.c
>> +++ b/drivers/media/v4l2-core/v4l2-event.c
>> @@ -318,3 +318,39 @@ int v4l2_event_subdev_unsubscribe(struct v4l2_subdev
>> *sd, struct v4l2_fh *fh, return v4l2_event_unsubscribe(fh, sub);
>> }
>> EXPORT_SYMBOL_GPL(v4l2_event_subdev_unsubscribe);
>> +
>> +static void v4l2_event_src_replace(struct v4l2_event *old,
>> + const struct v4l2_event *new)
>> +{
>> + u32 old_changes = old->u.src_change.changes;
>> +
>> + old->u.src_change = new->u.src_change;
>> + old->u.src_change.changes |= old_changes;
>> +}
>> +
>> +static void v4l2_event_src_merge(const struct v4l2_event *old,
>> + struct v4l2_event *new)
>> +{
>> + new->u.src_change.changes |= old->u.src_change.changes;
>> +}
>> +
>> +static const struct v4l2_subscribed_event_ops v4l2_event_src_ch_ops = {
>> + .replace = v4l2_event_src_replace,
>> + .merge = v4l2_event_src_merge,
>> +};
>> +
>> +int v4l2_src_change_event_subscribe(struct v4l2_fh *fh,
>> + const struct v4l2_event_subscription *sub)
>> +{
>> + if (sub->type == V4L2_EVENT_SOURCE_CHANGE)
>> + return v4l2_event_subscribe(fh, sub, 0, &v4l2_event_src_ch_ops);
>> + return -EINVAL;
>> +}
>> +EXPORT_SYMBOL_GPL(v4l2_src_change_event_subscribe);
>> +
>> +int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd,
>> + struct v4l2_fh *fh, struct v4l2_event_subscription *sub)
>> +{
>> + return v4l2_src_change_event_subscribe(fh, sub);
>> +}
>> +EXPORT_SYMBOL_GPL(v4l2_src_change_event_subdev_subscribe);
>> diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h
>> index be05d01..1ab9045 100644
>> --- a/include/media/v4l2-event.h
>> +++ b/include/media/v4l2-event.h
>> @@ -132,4 +132,8 @@ int v4l2_event_unsubscribe(struct v4l2_fh *fh,
>> void v4l2_event_unsubscribe_all(struct v4l2_fh *fh);
>> int v4l2_event_subdev_unsubscribe(struct v4l2_subdev *sd, struct v4l2_fh
>> *fh, struct v4l2_event_subscription *sub);
>> +int v4l2_src_change_event_subscribe(struct v4l2_fh *fh,
>> + const struct v4l2_event_subscription *sub);
>> +int v4l2_src_change_event_subdev_subscribe(struct v4l2_subdev *sd,
>> + struct v4l2_fh *fh, struct v4l2_event_subscription *sub);
>> #endif /* V4L2_EVENT_H */
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index ea468ee..b923d91 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -1765,6 +1765,7 @@ struct v4l2_streamparm {
>> #define V4L2_EVENT_EOS 2
>> #define V4L2_EVENT_CTRL 3
>> #define V4L2_EVENT_FRAME_SYNC 4
>> +#define V4L2_EVENT_SOURCE_CHANGE 5
>
> My last concern is about the event name (and the name of the related
> structure). Either this event applies to inputs only, in which case the
> documentation shouldn't mention the output number as it does above, or the
> event applies to both inputs and outputs, in which case the name "source" is
> too restrictive. I'd be tempted to go for the second option, even though I
> have less use cases in mind on the output side.
I don't think it makes sense to support this for outputs (I think I originally
suggested that, but I didn't think that through). One practical problem with
that approach would be with m2m devices because that makes it impossible to
tell the difference between a change on the capture side and a change on the
output side, the other is that normally outputs do not change since you are in
control w.r.t. to the format/resolution, etc.
If there is a need for format change events on an output, then I would expect
to see a separate event for that.
Regards,
Hans
>
>> #define V4L2_EVENT_PRIVATE_START 0x08000000
>>
>> /* Payload for V4L2_EVENT_VSYNC */
>> @@ -1796,12 +1797,19 @@ struct v4l2_event_frame_sync {
>> __u32 frame_sequence;
>> };
>>
>> +#define V4L2_EVENT_SRC_CH_RESOLUTION (1 << 0)
>> +
>> +struct v4l2_event_src_change {
>> + __u32 changes;
>> +};
>> +
>> struct v4l2_event {
>> __u32 type;
>> union {
>> struct v4l2_event_vsync vsync;
>> struct v4l2_event_ctrl ctrl;
>> struct v4l2_event_frame_sync frame_sync;
>> + struct v4l2_event_src_change src_change;
>> __u8 data[64];
>> } u;
>> __u32 pending;
>
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