[libcamera-devel] [PATCH v2 4/4] src: ipa: raspberrypi: Fix initial AGC oscillation for imx219 sensor

[Kieran Bingham]

Hi David,

On 26/11/2020 12:32, David Plowman wrote:
> The exposure times in the exposure modes were causing AGC oscillations
> because the algorithm was demanding long unachievable exposure times
> but, without working sensor metadata, thought it was getting them when
> actually it was not. We fix it by making the exposure profile request
> only achievable exposure times, as we do for the ov5647 tuning.
> 
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> Reviewed-by: Naushir Patuck <naush at raspberrypi.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  src/ipa/raspberrypi/data/imx219.json | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/src/ipa/raspberrypi/data/imx219.json b/src/ipa/raspberrypi/data/imx219.json
> index b03a7beb..212f8b9a 100644
> --- a/src/ipa/raspberrypi/data/imx219.json
> +++ b/src/ipa/raspberrypi/data/imx219.json
> @@ -133,7 +133,7 @@
>              {
>                  "shutter":
>                  [
> -                    100, 10000, 30000, 60000, 120000
> +                    100, 10000, 30000, 30000, 30000

Given the existing repetition, I assume an extra 30000 isn't an issue,
and it looks like this is just setting the shutter time on the modes array.

I also see shutter values of 120000 on the imx477, and in 'uncalibrated'.

I am going to wildly presume the imx477 is a better sensor, so it's more
appropriate there, or simply hasn't been considered yet (which isn't a
problem as this patch directly addresses the imx219).

I'm also curious about the high value in uncalibrated though. Should it
stay high, and as it's uncalibrated, it doesn't matter, as it's up to
the user to define and calibrate specific sensors?

I assume yes and those are only discussions so:

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

>                  ],
>                  "gain":
>                  [
> @@ -144,7 +144,7 @@
>              {
>                  "shutter":
>                  [
> -                    100, 5000, 10000, 20000, 120000
> +                    100, 5000, 10000, 20000, 30000
>                  ],
>                  "gain":
>                  [
> 

-- 
Regards
--
Kieran