[PATCH v2] v4l: Add source event change for bit-depth

[PATCH v2] v4l: Add source event change for bit-depth

[Stanimir Varbanov]

This event indicate that the source bit-depth is changed during
run-time. The client must get the new format and re-allocate buffers
for it. This can usually happens with video decoder (encoders) when
the bit-stream depth is changed from 8 to 10bits or vice versa.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
---
Change since v1: s/BITDEPTH/BIT_DEPTH

 Documentation/media/uapi/v4l/vidioc-dqevent.rst | 7 +++++++
 Documentation/media/videodev2.h.rst.exceptions  | 1 +
 include/uapi/linux/videodev2.h                  | 1 +
 3 files changed, 9 insertions(+)

diff --git a/Documentation/media/uapi/v4l/vidioc-dqevent.rst b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
index dea9c0cc00ab..f7782cbddc5f 100644
--- a/Documentation/media/uapi/v4l/vidioc-dqevent.rst
+++ b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
@@ -397,6 +397,13 @@ call.
 	that many devices are not able to recover from a temporary loss of
 	signal and so restarting streaming I/O is required in order for the
 	hardware to synchronize to the video signal.
+    * - ``V4L2_EVENT_SRC_CH_BIT_DEPTH``
+      - 0x0002
+      - This event gets triggered when bit-depth change is detected from a
+	video decoder. Applications will have to query the new pixel format
+	and re-negotiate the queue. In most cases the streaming must be stopped
+	and restarted (:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` followed by
+	:ref:`VIDIOC_STREAMON <VIDIOC_STREAMON>`).
 
 
 Return Value
diff --git a/Documentation/media/videodev2.h.rst.exceptions b/Documentation/media/videodev2.h.rst.exceptions
index 64d348e67df9..68ae00d7450f 100644
--- a/Documentation/media/videodev2.h.rst.exceptions
+++ b/Documentation/media/videodev2.h.rst.exceptions
@@ -478,6 +478,7 @@ replace define V4L2_EVENT_CTRL_CH_FLAGS ctrl-changes-flags
 replace define V4L2_EVENT_CTRL_CH_RANGE ctrl-changes-flags
 
 replace define V4L2_EVENT_SRC_CH_RESOLUTION src-changes-flags
+replace define V4L2_EVENT_SRC_CH_BIT_DEPTH src-changes-flags
 
 replace define V4L2_EVENT_MD_FL_HAVE_FRAME_SEQ :c:type:`v4l2_event_motion_det`
 
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 1050a75fb7ef..ecfdbaa60b05 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -2287,6 +2287,7 @@ struct v4l2_event_frame_sync {
 };
 
 #define V4L2_EVENT_SRC_CH_RESOLUTION		(1 << 0)
+#define V4L2_EVENT_SRC_CH_BIT_DEPTH		(1 << 1)
 
 struct v4l2_event_src_change {
 	__u32 changes;
-- 
2.17.1

Re: [PATCH v2] v4l: Add source event change for bit-depth

[Stanimir Varbanov]

Hi Hans,

On 5/8/19 2:37 PM, Stanimir Varbanov wrote:
> This event indicate that the source bit-depth is changed during
> run-time. The client must get the new format and re-allocate buffers
> for it. This can usually happens with video decoder (encoders) when
> the bit-stream depth is changed from 8 to 10bits or vice versa.
> 
> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
> ---
> Change since v1: s/BITDEPTH/BIT_DEPTH
> 
>  Documentation/media/uapi/v4l/vidioc-dqevent.rst | 7 +++++++
>  Documentation/media/videodev2.h.rst.exceptions  | 1 +
>  include/uapi/linux/videodev2.h                  | 1 +
>  3 files changed, 9 insertions(+)
> 
> diff --git a/Documentation/media/uapi/v4l/vidioc-dqevent.rst b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
> index dea9c0cc00ab..f7782cbddc5f 100644
> --- a/Documentation/media/uapi/v4l/vidioc-dqevent.rst
> +++ b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
> @@ -397,6 +397,13 @@ call.
>  	that many devices are not able to recover from a temporary loss of
>  	signal and so restarting streaming I/O is required in order for the
>  	hardware to synchronize to the video signal.
> +    * - ``V4L2_EVENT_SRC_CH_BIT_DEPTH``

I started to wonder isn't COLOR_DEPTH more appropriate? Bit-depth
doesn't describe what is actually deep.

-- 
regards,
Stan

Re: [PATCH v2] v4l: Add source event change for bit-depth

[Hans Verkuil]

On 5/8/19 5:34 PM, Stanimir Varbanov wrote:
> Hi Hans,
> 
> On 5/8/19 2:37 PM, Stanimir Varbanov wrote:
>> This event indicate that the source bit-depth is changed during
>> run-time. The client must get the new format and re-allocate buffers
>> for it. This can usually happens with video decoder (encoders) when
>> the bit-stream depth is changed from 8 to 10bits or vice versa.
>>
>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
>> ---
>> Change since v1: s/BITDEPTH/BIT_DEPTH
>>
>>  Documentation/media/uapi/v4l/vidioc-dqevent.rst | 7 +++++++
>>  Documentation/media/videodev2.h.rst.exceptions  | 1 +
>>  include/uapi/linux/videodev2.h                  | 1 +
>>  3 files changed, 9 insertions(+)
>>
>> diff --git a/Documentation/media/uapi/v4l/vidioc-dqevent.rst b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
>> index dea9c0cc00ab..f7782cbddc5f 100644
>> --- a/Documentation/media/uapi/v4l/vidioc-dqevent.rst
>> +++ b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
>> @@ -397,6 +397,13 @@ call.
>>  	that many devices are not able to recover from a temporary loss of
>>  	signal and so restarting streaming I/O is required in order for the
>>  	hardware to synchronize to the video signal.
>> +    * - ``V4L2_EVENT_SRC_CH_BIT_DEPTH``
> 
> I started to wonder isn't COLOR_DEPTH more appropriate? Bit-depth
> doesn't describe what is actually deep.
> 

I agree. COLOR_DEPTH is a better name.

Regards,

	Hans

Re: [PATCH v2] v4l: Add source event change for bit-depth

[Sakari Ailus]

On Wed, May 08, 2019 at 06:38:49PM +0200, Hans Verkuil wrote:
> On 5/8/19 5:34 PM, Stanimir Varbanov wrote:
> > Hi Hans,
> > 
> > On 5/8/19 2:37 PM, Stanimir Varbanov wrote:
> >> This event indicate that the source bit-depth is changed during
> >> run-time. The client must get the new format and re-allocate buffers
> >> for it. This can usually happens with video decoder (encoders) when
> >> the bit-stream depth is changed from 8 to 10bits or vice versa.
> >>
> >> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
> >> ---
> >> Change since v1: s/BITDEPTH/BIT_DEPTH
> >>
> >>  Documentation/media/uapi/v4l/vidioc-dqevent.rst | 7 +++++++
> >>  Documentation/media/videodev2.h.rst.exceptions  | 1 +
> >>  include/uapi/linux/videodev2.h                  | 1 +
> >>  3 files changed, 9 insertions(+)
> >>
> >> diff --git a/Documentation/media/uapi/v4l/vidioc-dqevent.rst b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
> >> index dea9c0cc00ab..f7782cbddc5f 100644
> >> --- a/Documentation/media/uapi/v4l/vidioc-dqevent.rst
> >> +++ b/Documentation/media/uapi/v4l/vidioc-dqevent.rst
> >> @@ -397,6 +397,13 @@ call.
> >>  	that many devices are not able to recover from a temporary loss of
> >>  	signal and so restarting streaming I/O is required in order for the
> >>  	hardware to synchronize to the video signal.
> >> +    * - ``V4L2_EVENT_SRC_CH_BIT_DEPTH``
> > 
> > I started to wonder isn't COLOR_DEPTH more appropriate? Bit-depth
> > doesn't describe what is actually deep.
> > 
> 
> I agree. COLOR_DEPTH is a better name.

Please add:

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

-- 
Sakari Ailus