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From: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
To: Jacopo Mondi <jacopo@jmondi.org>
Cc: mchehab@kernel.org, sakari.ailus@linux.intel.com,
	hverkuil@xs4all.nl, laurent.pinchart@ideasonboard.com,
	roman.kovalivskyi@globallogic.com,
	dave.stevenson@raspberrypi.org, naush@raspberrypi.com,
	mrodin@de.adit-jv.com, hugues.fruchet@st.com, mripard@kernel.org,
	aford173@gmail.com, sudipi@jp.adit-jv.com,
	andrew_gabbasov@mentor.com, erosca@de.adit-jv.com,
	linux-media@vger.kernel.org, libcamera-devel@lists.libcamera.org,
	dafna Hirschfeld <dafna3@gmail.com>
Subject: Re: [PATCH 20/25] media: ov5647: Program mode only if it has changed
Date: Tue, 30 Jun 2020 12:56:44 +0200
Message-ID: <de712b61-4b20-cfbd-ab79-d71bd1b7fc56@collabora.com> (raw)
In-Reply-To: <20200630100651.ikjcazgbvoq2hab4@uno.localdomain>



On 30.06.20 12:06, Jacopo Mondi wrote:
> Hi Dafna,
> 
> On Tue, Jun 30, 2020 at 11:32:12AM +0200, Dafna Hirschfeld wrote:
>>
>>
>> On 30.06.20 09:43, Jacopo Mondi wrote:
>>> Hi Dafna,
>>>
>>> On Mon, Jun 29, 2020 at 07:48:16PM +0200, Dafna Hirschfeld wrote:
>>>>
>>>>
>>>> On 23.06.20 18:55, Jacopo Mondi wrote:
>>>>> Store in the driver structure a pointer to the currently applied mode
>>>>> and program a new one at s_stream(1) time only if it has changed.
>>>>
>>>> Hi,
>>>> I think this can be more readably implemented with a 'is_streaming' boolean
>>>> field.
>>>
>>> How would you like to use an 'is_streaming' flag to decide if the
>>> sensor mode has to be updated ?
>>
>> since 'current_mode' is set to NULL upon `ov5647_stream_off`
>> and you return from 'ov5647_set_stream' immediately if 'mode == current_mode'
>> it seem very similar to returning immediately from 'ov5647_set_stream' if the
>> device is currently streaming.
> 
> No, the code returns immediately from ov5647_set_mode() if mode ==
> current_mode. The modes comparison makes sure the sensor is not
> reprogrammed if the mode hasn't changed. The remaning part of
> s_stream() is executed regardless of the mode configuration. Am I
> missing some part of the picture ?
> 
>>
>> But actually in this patch it seems to be possible to change the mode
>> while streaming, if the callbacks are executed:
>>
>> s_stream(1)
>> s_fmt
>> s_stream(1)
>>
>> which is maybe a bug?
> 
> The new format is stored in sensor->mode, and applied at the next
> s_stream(1) operation if it differs from the already programmed one,
> at least, this is how it is intended to work, have you found any
> failing s_stream/set_fmt/s_stream which could be caused by a bug ?

What I meant is that there could be valid sequence of calls

s_stream(enable=1)
s_fmt
s_stream(enable=1)

For example if two video devices are connected to the sensor and they
stream simultaneously. There was a discussion about adding a code to the core
to follow the s_stream callback and call it only if the subdev is not streaming
but currently subdevs should support it themselves.


Thanks,
Dafna

> 
> Thanks
>    j
>>
>> Thanks,
>> Dafna
>>
>>>
>>> Thanks
>>>      j
>>>
>>>
>>>>
>>>> Thanks,
>>>> Dafna
>>>>
>>>>>
>>>>> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
>>>>> ---
>>>>>     drivers/media/i2c/ov5647.c | 16 +++++++++++++++-
>>>>>     1 file changed, 15 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c
>>>>> index 39e320f321bd8..ac114269e1c73 100644
>>>>> --- a/drivers/media/i2c/ov5647.c
>>>>> +++ b/drivers/media/i2c/ov5647.c
>>>>> @@ -96,6 +96,7 @@ struct ov5647 {
>>>>>     	bool				clock_ncont;
>>>>>     	struct v4l2_ctrl_handler	ctrls;
>>>>>     	struct ov5647_mode		*mode;
>>>>> +	struct ov5647_mode		*current_mode;
>>>>>     };
>>>>>     static inline struct ov5647 *to_sensor(struct v4l2_subdev *sd)
>>>>> @@ -750,9 +751,13 @@ static int ov5647_set_virtual_channel(struct v4l2_subdev *sd, int channel)
>>>>>     static int ov5647_set_mode(struct v4l2_subdev *sd)
>>>>>     {
>>>>>     	struct i2c_client *client = v4l2_get_subdevdata(sd);
>>>>> +	struct ov5647 *sensor = to_sensor(sd);
>>>>>     	u8 resetval, rdval;
>>>>>     	int ret;
>>>>> +	if (sensor->mode == sensor->current_mode)
>>>>> +		return 0;
>>>>> +
>>>>>     	ret = ov5647_read(sd, OV5647_SW_STANDBY, &rdval);
>>>>>     	if (ret < 0)
>>>>>     		return ret;
>>>>> @@ -778,6 +783,8 @@ static int ov5647_set_mode(struct v4l2_subdev *sd)
>>>>>     			return ret;
>>>>>     	}
>>>>> +	sensor->current_mode = sensor->mode;
>>>>> +
>>>>>     	return 0;
>>>>>     }
>>>>> @@ -816,6 +823,7 @@ static int ov5647_stream_on(struct v4l2_subdev *sd)
>>>>>     static int ov5647_stream_off(struct v4l2_subdev *sd)
>>>>>     {
>>>>> +	struct ov5647 *sensor = to_sensor(sd);
>>>>>     	int ret;
>>>>>     	ret = ov5647_write(sd, OV5647_REG_MIPI_CTRL00, MIPI_CTRL00_CLOCK_LANE_GATE |
>>>>> @@ -827,7 +835,13 @@ static int ov5647_stream_off(struct v4l2_subdev *sd)
>>>>>     	if (ret < 0)
>>>>>     		return ret;
>>>>> -	return ov5647_write(sd, OV5640_REG_PAD_OUT, 0x01);
>>>>> +	ret = ov5647_write(sd, OV5640_REG_PAD_OUT, 0x01);
>>>>> +	if (ret < 0)
>>>>> +		return ret;
>>>>> +
>>>>> +	sensor->current_mode = NULL;
>>>>> +
>>>>> +	return 0;
>>>>>     }
>>>>>     static int set_sw_standby(struct v4l2_subdev *sd, bool standby)
>>>>>

  reply index

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-23 10:07 [PATCH 00/25] media: ov5647: Support RaspberryPi Camera Module v1 Jacopo Mondi
2020-06-23 10:07 ` [PATCH 01/25] dt-bindings: media: ov5647: Document pwdn-gpios Jacopo Mondi
2020-06-23 10:07 ` [PATCH 02/25] dt-bindings: media: ov5647: Document clock-noncontinuous Jacopo Mondi
2020-06-23 10:07 ` [PATCH 03/25] media: ov5647: Add support for PWDN GPIO Jacopo Mondi
2020-07-09 20:04   ` [libcamera-devel] " Dafna Hirschfeld
2020-07-14 12:45     ` Jacopo Mondi
2020-06-23 10:07 ` [PATCH 04/25] media: ov5647: Add support for non-continuous clock mode Jacopo Mondi
2020-06-23 10:07 ` [PATCH 05/25] media: ov5647: Add set_fmt and get_fmt calls Jacopo Mondi
2020-06-23 10:07 ` [PATCH 06/25] media: ov5647: Fix format initialization Jacopo Mondi
2020-06-23 10:07 ` [PATCH 07/25] media: ov5647: Fix style issues Jacopo Mondi
2020-06-23 10:07 ` [PATCH 08/25] media: ov5647: Replace license with SPDX identifier Jacopo Mondi
2020-06-23 10:07 ` [PATCH 09/25] media: ov5647: Fix return value from read/write Jacopo Mondi
2020-06-23 10:08 ` [PATCH 10/25] media: ov5647: Program mode at s_stream(1) time Jacopo Mondi
2020-06-23 16:42 ` [PATCH 11/25] media: ov5647: Implement enum_frame_size() Jacopo Mondi
2020-08-18  7:33   ` Sakari Ailus
2020-08-18  7:38     ` Sakari Ailus
2020-06-23 16:42 ` [PATCH 12/25] media: ov5647: Protect s_stream() with mutex Jacopo Mondi
2020-06-23 16:42 ` [PATCH 13/25] media: ov5647: Support gain, exposure and AWB controls Jacopo Mondi
2020-06-23 16:42 ` [PATCH 14/25] media: ov5647: Rationalize driver structure name Jacopo Mondi
2020-06-23 16:42 ` [PATCH 15/25] media: ov5647: Break out format handling Jacopo Mondi
2020-07-31 11:44   ` Sakari Ailus
2020-06-23 16:49 ` [PATCH 16/25] media: ov5647: Add support for get_selection() Jacopo Mondi
2020-07-09 19:56   ` [libcamera-devel] " Dafna Hirschfeld
2020-06-23 16:49 ` [PATCH 17/25] media: ov5647: Rename SBGGR8 VGA mode Jacopo Mondi
2020-06-23 16:49 ` [PATCH 18/25] media: ov5647: Add SGGBR10_1X10 modes Jacopo Mondi
2020-06-23 16:49 ` [PATCH 19/25] media: ov5647: Implement set_fmt pad operation Jacopo Mondi
2020-06-29 16:54   ` [libcamera-devel] " Dafna Hirschfeld
2020-06-30 10:13     ` Jacopo Mondi
2020-06-30 11:09       ` Dafna Hirschfeld
2020-06-23 16:55 ` [PATCH 20/25] media: ov5647: Program mode only if it has changed Jacopo Mondi
2020-06-29 17:48   ` Dafna Hirschfeld
2020-06-30  7:43     ` Jacopo Mondi
2020-06-30  9:32       ` Dafna Hirschfeld
2020-06-30 10:06         ` Jacopo Mondi
2020-06-30 10:56           ` Dafna Hirschfeld [this message]
2020-06-30 12:05             ` Jacopo Mondi
2020-06-30 13:01               ` Dafna Hirschfeld
2020-06-30 14:53                 ` [libcamera-devel] " Dave Stevenson
2020-06-30 15:11                   ` Dafna Hirschfeld
2020-07-01  7:25                 ` Laurent Pinchart
2020-07-03 12:21                   ` Jacopo Mondi
2020-07-03 16:33                     ` Laurent Pinchart
2020-06-23 16:55 ` [PATCH 21/25] media: ov5647: Set V4L2_SUBDEV_FL_HAS_EVENTS flag Jacopo Mondi
2020-06-23 16:55 ` [PATCH 22/25] media: ov5647: Support V4L2_CID_PIXEL_RATE Jacopo Mondi
2020-06-29 17:01   ` [libcamera-devel] " Dafna Hirschfeld
2020-06-29 21:25     ` Dave Stevenson
2020-06-30 15:13       ` Dave Stevenson
2020-07-01  7:21         ` Laurent Pinchart
2020-06-23 16:55 ` [PATCH 23/25] media: ov5647: Support V4L2_CID_HBLANK control Jacopo Mondi
2020-06-23 16:55 ` [PATCH 24/25] media: ov5647: Support V4L2_CID_VBLANK control Jacopo Mondi
2020-06-23 16:55 ` [PATCH 25/25] media: ov5647: Advertise the correct exposure range Jacopo Mondi
2020-06-29 17:33 ` [PATCH 00/25] media: ov5647: Support RaspberryPi Camera Module v1 Dafna Hirschfeld
2020-06-29 18:08   ` Dafna Hirschfeld
2020-07-10 15:59 ` Dafna Hirschfeld
2020-07-14 12:48   ` Jacopo Mondi

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