Hi Hans, Laurent,
On 05/09/14 18:45, Hans Verkuil wrote:
> 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.kk@xxxxxxxxxxx>
>>> ---
>>> 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.
>
Ok. I will modify the documentation to mention only about pad / input
index and keep the same name.
Regards
Arun
> 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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