diff mbox series

[1/5] media: ov2680: Stop sending more data then requested

Message ID 20240216223237.326523-2-hdegoede@redhat.com (mailing list archive)
State New, archived
Headers show
Series media: ov2680: Add all controls required by libcamera | expand

Commit Message

Hans de Goede Feb. 16, 2024, 10:32 p.m. UTC
There is no reason to send OV2680_END_MARGIN extra columns on top of
the mode width and the same for sending extra lines over the mode height.

This sending of extra lines/columns was inherited from the atomisp
ov2680 driver, it is unclear why this was done and this complicates
adding V4L2_CID_VBLANK support, so remove it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/media/i2c/ov2680.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

Comments

Kieran Bingham Feb. 17, 2024, 3:38 p.m. UTC | #1
Quoting Hans de Goede (2024-02-16 22:32:33)
> There is no reason to send OV2680_END_MARGIN extra columns on top of
> the mode width and the same for sending extra lines over the mode height.
> 
> This sending of extra lines/columns was inherited from the atomisp
> ov2680 driver, it is unclear why this was done and this complicates
> adding V4L2_CID_VBLANK support, so remove it.

Was this some niave way of adding some HBLANK to let the AtomISP keep up
with processing each line?

Or is it an optical black region? or padding? (I hit issues around that
on the IMX283 lately).

Is this a sensor you have and can visually check?

> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/media/i2c/ov2680.c | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov2680.c b/drivers/media/i2c/ov2680.c
> index 39d321e2b7f9..5b04c6c0554a 100644
> --- a/drivers/media/i2c/ov2680.c
> +++ b/drivers/media/i2c/ov2680.c
> @@ -86,9 +86,6 @@
>  #define OV2680_PIXELS_PER_LINE                 1704
>  #define OV2680_LINES_PER_FRAME                 1294
>  
> -/* If possible send 16 extra rows / lines to the ISP as padding */
> -#define OV2680_END_MARGIN                      16
> -
>  /* Max exposure time is VTS - 8 */
>  #define OV2680_INTEGRATION_TIME_MARGIN         8
>  
> @@ -359,11 +356,9 @@ static void ov2680_calc_mode(struct ov2680_dev *sensor)
>         sensor->mode.v_start = (sensor->mode.crop.top +
>                                 (sensor->mode.crop.height - height) / 2) & ~1;
>         sensor->mode.h_end =
> -               min(sensor->mode.h_start + width + OV2680_END_MARGIN - 1,
> -                   OV2680_NATIVE_WIDTH - 1);
> +               min(sensor->mode.h_start + width - 1, OV2680_NATIVE_WIDTH - 1);
>         sensor->mode.v_end =
> -               min(sensor->mode.v_start + height + OV2680_END_MARGIN - 1,
> -                   OV2680_NATIVE_HEIGHT - 1);
> +               min(sensor->mode.v_start + height - 1, OV2680_NATIVE_HEIGHT - 1);
>         sensor->mode.h_output_size = orig_width;
>         sensor->mode.v_output_size = orig_height;
>         sensor->mode.hts = OV2680_PIXELS_PER_LINE;

Especially as seeing hts = OV2680_PIXELS_PER_LINE it does sound like the
margin is superfluous.

> -- 
> 2.43.0
>
Hans de Goede April 10, 2024, 11:27 a.m. UTC | #2
Hi,

Sorry for being very slow with replying to this.

On 2/17/24 4:38 PM, Kieran Bingham wrote:
> Quoting Hans de Goede (2024-02-16 22:32:33)
>> There is no reason to send OV2680_END_MARGIN extra columns on top of
>> the mode width and the same for sending extra lines over the mode height.
>>
>> This sending of extra lines/columns was inherited from the atomisp
>> ov2680 driver, it is unclear why this was done and this complicates
>> adding V4L2_CID_VBLANK support, so remove it.
> 
> Was this some niave way of adding some HBLANK to let the AtomISP keep up
> with processing each line?

The total amount of pixels per line and of lines per frame are fixed:

#define OV2680_PIXELS_PER_LINE                 1704
#define OV2680_LINES_PER_FRAME                 1294

This patch only changes the h_end and v_end registers which
before AFAIK configure when to stop sending actual pixel
data (and move over to sending blanking data). So this was
actually requesting for more pixels to be send then there are.

> Or is it an optical black region? or padding? (I hit issues around that
> on the IMX283 lately).

AFAICT (from the datasheet) there is no optical black region, so
this really just seemed some weirdness in the original Android
kernel driver where this is derived from.

The datasheet says:

"2.4 pixel array addresses
The addressable pixel array of the OV2680 sensor is 1616 x 1216. The addressed region of the pixel array is controlled
by the horizontal_start, vertical_start, horizontal_end and vertical_end registers. The start and end addresses are limited
to even and odd numbers, respectively, to ensure that there is always an even number of pixels read out in x and y."

> Is this a sensor you have and can visually check?

Yes this is a sensor which I have, not sure what you mean with
visually check. The atomisp driver does not allow getting the full
resolution as the ISP needs some padding. So the max I can get
is 1600x1200. I think the original Android code just added
the 16 extra pixels needed by the ISP to h_end and v_end
twice. Starting with the extra 16 pixels which are actually
there on the sensor and then adding an extra 16 which are
fully made up by the driver author and somehow this still
works (I guess the sensor just sends all 0 data for these).


> 
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>>  drivers/media/i2c/ov2680.c | 9 ++-------
>>  1 file changed, 2 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/media/i2c/ov2680.c b/drivers/media/i2c/ov2680.c
>> index 39d321e2b7f9..5b04c6c0554a 100644
>> --- a/drivers/media/i2c/ov2680.c
>> +++ b/drivers/media/i2c/ov2680.c
>> @@ -86,9 +86,6 @@
>>  #define OV2680_PIXELS_PER_LINE                 1704
>>  #define OV2680_LINES_PER_FRAME                 1294
>>  
>> -/* If possible send 16 extra rows / lines to the ISP as padding */
>> -#define OV2680_END_MARGIN                      16
>> -
>>  /* Max exposure time is VTS - 8 */
>>  #define OV2680_INTEGRATION_TIME_MARGIN         8
>>  
>> @@ -359,11 +356,9 @@ static void ov2680_calc_mode(struct ov2680_dev *sensor)
>>         sensor->mode.v_start = (sensor->mode.crop.top +
>>                                 (sensor->mode.crop.height - height) / 2) & ~1;
>>         sensor->mode.h_end =
>> -               min(sensor->mode.h_start + width + OV2680_END_MARGIN - 1,
>> -                   OV2680_NATIVE_WIDTH - 1);
>> +               min(sensor->mode.h_start + width - 1, OV2680_NATIVE_WIDTH - 1);
>>         sensor->mode.v_end =
>> -               min(sensor->mode.v_start + height + OV2680_END_MARGIN - 1,
>> -                   OV2680_NATIVE_HEIGHT - 1);
>> +               min(sensor->mode.v_start + height - 1, OV2680_NATIVE_HEIGHT - 1);
>>         sensor->mode.h_output_size = orig_width;
>>         sensor->mode.v_output_size = orig_height;
>>         sensor->mode.hts = OV2680_PIXELS_PER_LINE;
> 
> Especially as seeing hts = OV2680_PIXELS_PER_LINE it does sound like the
> margin is superfluous.

Right.

Regards,

Hans
Kieran Bingham April 10, 2024, 9:24 p.m. UTC | #3
Quoting Hans de Goede (2024-04-10 12:27:03)
> Hi,
> 
> Sorry for being very slow with replying to this.
> 

No worries,


> On 2/17/24 4:38 PM, Kieran Bingham wrote:
> > Quoting Hans de Goede (2024-02-16 22:32:33)
> >> There is no reason to send OV2680_END_MARGIN extra columns on top of
> >> the mode width and the same for sending extra lines over the mode height.
> >>
> >> This sending of extra lines/columns was inherited from the atomisp
> >> ov2680 driver, it is unclear why this was done and this complicates
> >> adding V4L2_CID_VBLANK support, so remove it.
> > 
> > Was this some niave way of adding some HBLANK to let the AtomISP keep up
> > with processing each line?
> 
> The total amount of pixels per line and of lines per frame are fixed:
> 
> #define OV2680_PIXELS_PER_LINE                 1704
> #define OV2680_LINES_PER_FRAME                 1294
> 
> This patch only changes the h_end and v_end registers which
> before AFAIK configure when to stop sending actual pixel
> data (and move over to sending blanking data). So this was
> actually requesting for more pixels to be send then there are.
> 
> > Or is it an optical black region? or padding? (I hit issues around that
> > on the IMX283 lately).
> 
> AFAICT (from the datasheet) there is no optical black region, so
> this really just seemed some weirdness in the original Android
> kernel driver where this is derived from.
> 
> The datasheet says:
> 
> "2.4 pixel array addresses
> The addressable pixel array of the OV2680 sensor is 1616 x 1216. The addressed region of the pixel array is controlled
> by the horizontal_start, vertical_start, horizontal_end and vertical_end registers. The start and end addresses are limited
> to even and odd numbers, respectively, to ensure that there is always an even number of pixels read out in x and y."
> 
> > Is this a sensor you have and can visually check?
> 
> Yes this is a sensor which I have, not sure what you mean with
> visually check. The atomisp driver does not allow getting the full

Me neither at this point. I was probably worried about the impact of
changing these values causing visible issues in the stride/line widths
or such. But if you're testing and capturing images successfully I'm not
worried now.


> resolution as the ISP needs some padding. So the max I can get
> is 1600x1200. I think the original Android code just added
> the 16 extra pixels needed by the ISP to h_end and v_end
> twice. Starting with the extra 16 pixels which are actually
> there on the sensor and then adding an extra 16 which are
> fully made up by the driver author and somehow this still
> works (I guess the sensor just sends all 0 data for these).

Or maybe that was the part to check visually ;-) But I guess it's not
easy to capture the full raw images for these ?

> > 
> >> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> >> ---
> >>  drivers/media/i2c/ov2680.c | 9 ++-------
> >>  1 file changed, 2 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/drivers/media/i2c/ov2680.c b/drivers/media/i2c/ov2680.c
> >> index 39d321e2b7f9..5b04c6c0554a 100644
> >> --- a/drivers/media/i2c/ov2680.c
> >> +++ b/drivers/media/i2c/ov2680.c
> >> @@ -86,9 +86,6 @@
> >>  #define OV2680_PIXELS_PER_LINE                 1704
> >>  #define OV2680_LINES_PER_FRAME                 1294
> >>  
> >> -/* If possible send 16 extra rows / lines to the ISP as padding */
> >> -#define OV2680_END_MARGIN                      16
> >> -
> >>  /* Max exposure time is VTS - 8 */
> >>  #define OV2680_INTEGRATION_TIME_MARGIN         8
> >>  
> >> @@ -359,11 +356,9 @@ static void ov2680_calc_mode(struct ov2680_dev *sensor)
> >>         sensor->mode.v_start = (sensor->mode.crop.top +
> >>                                 (sensor->mode.crop.height - height) / 2) & ~1;
> >>         sensor->mode.h_end =
> >> -               min(sensor->mode.h_start + width + OV2680_END_MARGIN - 1,
> >> -                   OV2680_NATIVE_WIDTH - 1);
> >> +               min(sensor->mode.h_start + width - 1, OV2680_NATIVE_WIDTH - 1);
> >>         sensor->mode.v_end =
> >> -               min(sensor->mode.v_start + height + OV2680_END_MARGIN - 1,
> >> -                   OV2680_NATIVE_HEIGHT - 1);
> >> +               min(sensor->mode.v_start + height - 1, OV2680_NATIVE_HEIGHT - 1);
> >>         sensor->mode.h_output_size = orig_width;
> >>         sensor->mode.v_output_size = orig_height;
> >>         sensor->mode.hts = OV2680_PIXELS_PER_LINE;
> > 
> > Especially as seeing hts = OV2680_PIXELS_PER_LINE it does sound like the
> > margin is superfluous.
> 
> Right.
> 
> Regards,
> 
> Hans
> 
>
Hans de Goede April 11, 2024, 12:19 p.m. UTC | #4
Hi,

On 4/10/24 11:24 PM, Kieran Bingham wrote:
> Quoting Hans de Goede (2024-04-10 12:27:03)
>> Hi,
>>
>> Sorry for being very slow with replying to this.
>>
> 
> No worries,
> 
> 
>> On 2/17/24 4:38 PM, Kieran Bingham wrote:
>>> Quoting Hans de Goede (2024-02-16 22:32:33)
>>>> There is no reason to send OV2680_END_MARGIN extra columns on top of
>>>> the mode width and the same for sending extra lines over the mode height.
>>>>
>>>> This sending of extra lines/columns was inherited from the atomisp
>>>> ov2680 driver, it is unclear why this was done and this complicates
>>>> adding V4L2_CID_VBLANK support, so remove it.
>>>
>>> Was this some niave way of adding some HBLANK to let the AtomISP keep up
>>> with processing each line?
>>
>> The total amount of pixels per line and of lines per frame are fixed:
>>
>> #define OV2680_PIXELS_PER_LINE                 1704
>> #define OV2680_LINES_PER_FRAME                 1294
>>
>> This patch only changes the h_end and v_end registers which
>> before AFAIK configure when to stop sending actual pixel
>> data (and move over to sending blanking data). So this was
>> actually requesting for more pixels to be send then there are.
>>
>>> Or is it an optical black region? or padding? (I hit issues around that
>>> on the IMX283 lately).
>>
>> AFAICT (from the datasheet) there is no optical black region, so
>> this really just seemed some weirdness in the original Android
>> kernel driver where this is derived from.
>>
>> The datasheet says:
>>
>> "2.4 pixel array addresses
>> The addressable pixel array of the OV2680 sensor is 1616 x 1216. The addressed region of the pixel array is controlled
>> by the horizontal_start, vertical_start, horizontal_end and vertical_end registers. The start and end addresses are limited
>> to even and odd numbers, respectively, to ensure that there is always an even number of pixels read out in x and y."
>>
>>> Is this a sensor you have and can visually check?
>>
>> Yes this is a sensor which I have, not sure what you mean with
>> visually check. The atomisp driver does not allow getting the full
> 
> Me neither at this point. I was probably worried about the impact of
> changing these values causing visible issues in the stride/line widths
> or such. But if you're testing and capturing images successfully I'm not
> worried now.
> 
> 
>> resolution as the ISP needs some padding. So the max I can get
>> is 1600x1200. I think the original Android code just added
>> the 16 extra pixels needed by the ISP to h_end and v_end
>> twice. Starting with the extra 16 pixels which are actually
>> there on the sensor and then adding an extra 16 which are
>> fully made up by the driver author and somehow this still
>> works (I guess the sensor just sends all 0 data for these).
> 
> Or maybe that was the part to check visually ;-) But I guess it's not
> easy to capture the full raw images for these ?

Besides a bunch of devices with the atomisp I also have 1 IPU3
based device with an ov2680 sensor. So I could capture full
raw resolution there. But unless I modify the driver full
raw resolution is 1616x1216 where as before this patch the driver
sets v_end to 1631 so more pixels then the full size, which is
the weirdness this patch corrects.

Regards,

Hans




> 
>>>
>>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>>> ---
>>>>  drivers/media/i2c/ov2680.c | 9 ++-------
>>>>  1 file changed, 2 insertions(+), 7 deletions(-)
>>>>
>>>> diff --git a/drivers/media/i2c/ov2680.c b/drivers/media/i2c/ov2680.c
>>>> index 39d321e2b7f9..5b04c6c0554a 100644
>>>> --- a/drivers/media/i2c/ov2680.c
>>>> +++ b/drivers/media/i2c/ov2680.c
>>>> @@ -86,9 +86,6 @@
>>>>  #define OV2680_PIXELS_PER_LINE                 1704
>>>>  #define OV2680_LINES_PER_FRAME                 1294
>>>>  
>>>> -/* If possible send 16 extra rows / lines to the ISP as padding */
>>>> -#define OV2680_END_MARGIN                      16
>>>> -
>>>>  /* Max exposure time is VTS - 8 */
>>>>  #define OV2680_INTEGRATION_TIME_MARGIN         8
>>>>  
>>>> @@ -359,11 +356,9 @@ static void ov2680_calc_mode(struct ov2680_dev *sensor)
>>>>         sensor->mode.v_start = (sensor->mode.crop.top +
>>>>                                 (sensor->mode.crop.height - height) / 2) & ~1;
>>>>         sensor->mode.h_end =
>>>> -               min(sensor->mode.h_start + width + OV2680_END_MARGIN - 1,
>>>> -                   OV2680_NATIVE_WIDTH - 1);
>>>> +               min(sensor->mode.h_start + width - 1, OV2680_NATIVE_WIDTH - 1);
>>>>         sensor->mode.v_end =
>>>> -               min(sensor->mode.v_start + height + OV2680_END_MARGIN - 1,
>>>> -                   OV2680_NATIVE_HEIGHT - 1);
>>>> +               min(sensor->mode.v_start + height - 1, OV2680_NATIVE_HEIGHT - 1);
>>>>         sensor->mode.h_output_size = orig_width;
>>>>         sensor->mode.v_output_size = orig_height;
>>>>         sensor->mode.hts = OV2680_PIXELS_PER_LINE;
>>>
>>> Especially as seeing hts = OV2680_PIXELS_PER_LINE it does sound like the
>>> margin is superfluous.
>>
>> Right.
>>
>> Regards,
>>
>> Hans
>>
>>
>
Kieran Bingham April 14, 2024, 10:03 p.m. UTC | #5
Hi Hans,

Quoting Hans de Goede (2024-04-11 13:19:15)
> Hi,
> 
> On 4/10/24 11:24 PM, Kieran Bingham wrote:
> > Quoting Hans de Goede (2024-04-10 12:27:03)
> >> Hi,
> >>
> >> Sorry for being very slow with replying to this.
> >>
> > 
> > No worries,
> > 
> > 
> >> On 2/17/24 4:38 PM, Kieran Bingham wrote:
> >>> Quoting Hans de Goede (2024-02-16 22:32:33)
> >>>> There is no reason to send OV2680_END_MARGIN extra columns on top of
> >>>> the mode width and the same for sending extra lines over the mode height.
> >>>>
> >>>> This sending of extra lines/columns was inherited from the atomisp
> >>>> ov2680 driver, it is unclear why this was done and this complicates
> >>>> adding V4L2_CID_VBLANK support, so remove it.
> >>>
> >>> Was this some niave way of adding some HBLANK to let the AtomISP keep up
> >>> with processing each line?
> >>
> >> The total amount of pixels per line and of lines per frame are fixed:
> >>
> >> #define OV2680_PIXELS_PER_LINE                 1704
> >> #define OV2680_LINES_PER_FRAME                 1294
> >>
> >> This patch only changes the h_end and v_end registers which
> >> before AFAIK configure when to stop sending actual pixel
> >> data (and move over to sending blanking data). So this was
> >> actually requesting for more pixels to be send then there are.
> >>
> >>> Or is it an optical black region? or padding? (I hit issues around that
> >>> on the IMX283 lately).
> >>
> >> AFAICT (from the datasheet) there is no optical black region, so
> >> this really just seemed some weirdness in the original Android
> >> kernel driver where this is derived from.
> >>
> >> The datasheet says:
> >>
> >> "2.4 pixel array addresses
> >> The addressable pixel array of the OV2680 sensor is 1616 x 1216. The addressed region of the pixel array is controlled
> >> by the horizontal_start, vertical_start, horizontal_end and vertical_end registers. The start and end addresses are limited
> >> to even and odd numbers, respectively, to ensure that there is always an even number of pixels read out in x and y."
> >>
> >>> Is this a sensor you have and can visually check?
> >>
> >> Yes this is a sensor which I have, not sure what you mean with
> >> visually check. The atomisp driver does not allow getting the full
> > 
> > Me neither at this point. I was probably worried about the impact of
> > changing these values causing visible issues in the stride/line widths
> > or such. But if you're testing and capturing images successfully I'm not
> > worried now.
> > 
> > 
> >> resolution as the ISP needs some padding. So the max I can get
> >> is 1600x1200. I think the original Android code just added
> >> the 16 extra pixels needed by the ISP to h_end and v_end
> >> twice. Starting with the extra 16 pixels which are actually
> >> there on the sensor and then adding an extra 16 which are
> >> fully made up by the driver author and somehow this still
> >> works (I guess the sensor just sends all 0 data for these).
> > 
> > Or maybe that was the part to check visually ;-) But I guess it's not
> > easy to capture the full raw images for these ?
> 
> Besides a bunch of devices with the atomisp I also have 1 IPU3
> based device with an ov2680 sensor. So I could capture full
> raw resolution there. But unless I modify the driver full
> raw resolution is 1616x1216 where as before this patch the driver
> sets v_end to 1631 so more pixels then the full size, which is
> the weirdness this patch corrects.

That sounds reasonable to me, thank you for all the explanations.

I don't object to this patch, but I don't have a way to test, nor
further verify this one myself specifically.

But, the commit does reflect what the commit message states ... so I
guess that's a ...

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>


> Regards,
> 
> Hans
> 
> 
> 
> 
> > 
> >>>
> >>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> >>>> ---
> >>>>  drivers/media/i2c/ov2680.c | 9 ++-------
> >>>>  1 file changed, 2 insertions(+), 7 deletions(-)
> >>>>
> >>>> diff --git a/drivers/media/i2c/ov2680.c b/drivers/media/i2c/ov2680.c
> >>>> index 39d321e2b7f9..5b04c6c0554a 100644
> >>>> --- a/drivers/media/i2c/ov2680.c
> >>>> +++ b/drivers/media/i2c/ov2680.c
> >>>> @@ -86,9 +86,6 @@
> >>>>  #define OV2680_PIXELS_PER_LINE                 1704
> >>>>  #define OV2680_LINES_PER_FRAME                 1294
> >>>>  
> >>>> -/* If possible send 16 extra rows / lines to the ISP as padding */
> >>>> -#define OV2680_END_MARGIN                      16
> >>>> -
> >>>>  /* Max exposure time is VTS - 8 */
> >>>>  #define OV2680_INTEGRATION_TIME_MARGIN         8
> >>>>  
> >>>> @@ -359,11 +356,9 @@ static void ov2680_calc_mode(struct ov2680_dev *sensor)
> >>>>         sensor->mode.v_start = (sensor->mode.crop.top +
> >>>>                                 (sensor->mode.crop.height - height) / 2) & ~1;
> >>>>         sensor->mode.h_end =
> >>>> -               min(sensor->mode.h_start + width + OV2680_END_MARGIN - 1,
> >>>> -                   OV2680_NATIVE_WIDTH - 1);
> >>>> +               min(sensor->mode.h_start + width - 1, OV2680_NATIVE_WIDTH - 1);
> >>>>         sensor->mode.v_end =
> >>>> -               min(sensor->mode.v_start + height + OV2680_END_MARGIN - 1,
> >>>> -                   OV2680_NATIVE_HEIGHT - 1);
> >>>> +               min(sensor->mode.v_start + height - 1, OV2680_NATIVE_HEIGHT - 1);
> >>>>         sensor->mode.h_output_size = orig_width;
> >>>>         sensor->mode.v_output_size = orig_height;
> >>>>         sensor->mode.hts = OV2680_PIXELS_PER_LINE;
> >>>
> >>> Especially as seeing hts = OV2680_PIXELS_PER_LINE it does sound like the
> >>> margin is superfluous.
> >>
> >> Right.
> >>
> >> Regards,
> >>
> >> Hans
> >>
> >>
> > 
>
Hans de Goede April 15, 2024, 8:38 a.m. UTC | #6
Hi Kieran,

On 4/15/24 12:03 AM, Kieran Bingham wrote:
> Hi Hans,
> 
> Quoting Hans de Goede (2024-04-11 13:19:15)
>> Hi,
>>
>> On 4/10/24 11:24 PM, Kieran Bingham wrote:
>>> Quoting Hans de Goede (2024-04-10 12:27:03)
>>>> Hi,
>>>>
>>>> Sorry for being very slow with replying to this.
>>>>
>>>
>>> No worries,
>>>
>>>
>>>> On 2/17/24 4:38 PM, Kieran Bingham wrote:
>>>>> Quoting Hans de Goede (2024-02-16 22:32:33)
>>>>>> There is no reason to send OV2680_END_MARGIN extra columns on top of
>>>>>> the mode width and the same for sending extra lines over the mode height.
>>>>>>
>>>>>> This sending of extra lines/columns was inherited from the atomisp
>>>>>> ov2680 driver, it is unclear why this was done and this complicates
>>>>>> adding V4L2_CID_VBLANK support, so remove it.
>>>>>
>>>>> Was this some niave way of adding some HBLANK to let the AtomISP keep up
>>>>> with processing each line?
>>>>
>>>> The total amount of pixels per line and of lines per frame are fixed:
>>>>
>>>> #define OV2680_PIXELS_PER_LINE                 1704
>>>> #define OV2680_LINES_PER_FRAME                 1294
>>>>
>>>> This patch only changes the h_end and v_end registers which
>>>> before AFAIK configure when to stop sending actual pixel
>>>> data (and move over to sending blanking data). So this was
>>>> actually requesting for more pixels to be send then there are.
>>>>
>>>>> Or is it an optical black region? or padding? (I hit issues around that
>>>>> on the IMX283 lately).
>>>>
>>>> AFAICT (from the datasheet) there is no optical black region, so
>>>> this really just seemed some weirdness in the original Android
>>>> kernel driver where this is derived from.
>>>>
>>>> The datasheet says:
>>>>
>>>> "2.4 pixel array addresses
>>>> The addressable pixel array of the OV2680 sensor is 1616 x 1216. The addressed region of the pixel array is controlled
>>>> by the horizontal_start, vertical_start, horizontal_end and vertical_end registers. The start and end addresses are limited
>>>> to even and odd numbers, respectively, to ensure that there is always an even number of pixels read out in x and y."
>>>>
>>>>> Is this a sensor you have and can visually check?
>>>>
>>>> Yes this is a sensor which I have, not sure what you mean with
>>>> visually check. The atomisp driver does not allow getting the full
>>>
>>> Me neither at this point. I was probably worried about the impact of
>>> changing these values causing visible issues in the stride/line widths
>>> or such. But if you're testing and capturing images successfully I'm not
>>> worried now.
>>>
>>>
>>>> resolution as the ISP needs some padding. So the max I can get
>>>> is 1600x1200. I think the original Android code just added
>>>> the 16 extra pixels needed by the ISP to h_end and v_end
>>>> twice. Starting with the extra 16 pixels which are actually
>>>> there on the sensor and then adding an extra 16 which are
>>>> fully made up by the driver author and somehow this still
>>>> works (I guess the sensor just sends all 0 data for these).
>>>
>>> Or maybe that was the part to check visually ;-) But I guess it's not
>>> easy to capture the full raw images for these ?
>>
>> Besides a bunch of devices with the atomisp I also have 1 IPU3
>> based device with an ov2680 sensor. So I could capture full
>> raw resolution there. But unless I modify the driver full
>> raw resolution is 1616x1216 where as before this patch the driver
>> sets v_end to 1631 so more pixels then the full size, which is
>> the weirdness this patch corrects.
> 
> That sounds reasonable to me, thank you for all the explanations.
> 
> I don't object to this patch, but I don't have a way to test, nor
> further verify this one myself specifically.
> 
> But, the commit does reflect what the commit message states ... so I
> guess that's a ...
> 
> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

Thank you.

Since this patch set is quite old by now I'll go and prepare a
resend with all the collected tags soon.

Regards,

Hans



>>>>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>>>>> ---
>>>>>>  drivers/media/i2c/ov2680.c | 9 ++-------
>>>>>>  1 file changed, 2 insertions(+), 7 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/media/i2c/ov2680.c b/drivers/media/i2c/ov2680.c
>>>>>> index 39d321e2b7f9..5b04c6c0554a 100644
>>>>>> --- a/drivers/media/i2c/ov2680.c
>>>>>> +++ b/drivers/media/i2c/ov2680.c
>>>>>> @@ -86,9 +86,6 @@
>>>>>>  #define OV2680_PIXELS_PER_LINE                 1704
>>>>>>  #define OV2680_LINES_PER_FRAME                 1294
>>>>>>  
>>>>>> -/* If possible send 16 extra rows / lines to the ISP as padding */
>>>>>> -#define OV2680_END_MARGIN                      16
>>>>>> -
>>>>>>  /* Max exposure time is VTS - 8 */
>>>>>>  #define OV2680_INTEGRATION_TIME_MARGIN         8
>>>>>>  
>>>>>> @@ -359,11 +356,9 @@ static void ov2680_calc_mode(struct ov2680_dev *sensor)
>>>>>>         sensor->mode.v_start = (sensor->mode.crop.top +
>>>>>>                                 (sensor->mode.crop.height - height) / 2) & ~1;
>>>>>>         sensor->mode.h_end =
>>>>>> -               min(sensor->mode.h_start + width + OV2680_END_MARGIN - 1,
>>>>>> -                   OV2680_NATIVE_WIDTH - 1);
>>>>>> +               min(sensor->mode.h_start + width - 1, OV2680_NATIVE_WIDTH - 1);
>>>>>>         sensor->mode.v_end =
>>>>>> -               min(sensor->mode.v_start + height + OV2680_END_MARGIN - 1,
>>>>>> -                   OV2680_NATIVE_HEIGHT - 1);
>>>>>> +               min(sensor->mode.v_start + height - 1, OV2680_NATIVE_HEIGHT - 1);
>>>>>>         sensor->mode.h_output_size = orig_width;
>>>>>>         sensor->mode.v_output_size = orig_height;
>>>>>>         sensor->mode.hts = OV2680_PIXELS_PER_LINE;
>>>>>
>>>>> Especially as seeing hts = OV2680_PIXELS_PER_LINE it does sound like the
>>>>> margin is superfluous.
>>>>
>>>> Right.
>>>>
>>>> Regards,
>>>>
>>>> Hans
>>>>
>>>>
>>>
>>
>
diff mbox series

Patch

diff --git a/drivers/media/i2c/ov2680.c b/drivers/media/i2c/ov2680.c
index 39d321e2b7f9..5b04c6c0554a 100644
--- a/drivers/media/i2c/ov2680.c
+++ b/drivers/media/i2c/ov2680.c
@@ -86,9 +86,6 @@ 
 #define OV2680_PIXELS_PER_LINE			1704
 #define OV2680_LINES_PER_FRAME			1294
 
-/* If possible send 16 extra rows / lines to the ISP as padding */
-#define OV2680_END_MARGIN			16
-
 /* Max exposure time is VTS - 8 */
 #define OV2680_INTEGRATION_TIME_MARGIN		8
 
@@ -359,11 +356,9 @@  static void ov2680_calc_mode(struct ov2680_dev *sensor)
 	sensor->mode.v_start = (sensor->mode.crop.top +
 				(sensor->mode.crop.height - height) / 2) & ~1;
 	sensor->mode.h_end =
-		min(sensor->mode.h_start + width + OV2680_END_MARGIN - 1,
-		    OV2680_NATIVE_WIDTH - 1);
+		min(sensor->mode.h_start + width - 1, OV2680_NATIVE_WIDTH - 1);
 	sensor->mode.v_end =
-		min(sensor->mode.v_start + height + OV2680_END_MARGIN - 1,
-		    OV2680_NATIVE_HEIGHT - 1);
+		min(sensor->mode.v_start + height - 1, OV2680_NATIVE_HEIGHT - 1);
 	sensor->mode.h_output_size = orig_width;
 	sensor->mode.v_output_size = orig_height;
 	sensor->mode.hts = OV2680_PIXELS_PER_LINE;