[libcamera-devel] [PATCH] ipa: rpi: Avoid skipping IPAs on the first frame after the drop frames

[Naushir Patuck]

Hi David,

Thank you for fixing this, quite a subtle bug!

On Thu, 28 Sept 2023 at 10:41, David Plowman via libcamera-devel
<libcamera-devel at lists.libcamera.org> wrote:
>
> We avoid skipping the IPAs while frameCount_ is less then

s/then/than/

> dropFrameCount_, indicating that these frames will not be sent to the
> application. This means that when these numbers are equal then this is
> the first frame the application will get, so again, we must avoid
> skipping the IPAs. Consequently the test here must avoid the case of
> equality.
>
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>

Perhaps add a Fixes: 51533fecae8 ("ipa: rpi: Fix frame count logic
when running algorithms")?

Reviewed-by: Naushir Patuck <naush at raspberrypi.com>

> ---
>  src/ipa/rpi/common/ipa_base.cpp | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/ipa/rpi/common/ipa_base.cpp b/src/ipa/rpi/common/ipa_base.cpp
> index 551adadf..5df1998c 100644
> --- a/src/ipa/rpi/common/ipa_base.cpp
> +++ b/src/ipa/rpi/common/ipa_base.cpp
> @@ -409,7 +409,7 @@ void IpaBase::prepareIsp(const PrepareParams &params)
>
>         /* Allow a 10% margin on the comparison below. */
>         Duration delta = (frameTimestamp - lastRunTimestamp_) * 1.0ns;
> -       if (lastRunTimestamp_ && frameCount_ >= dropFrameCount_ &&
> +       if (lastRunTimestamp_ && frameCount_ > dropFrameCount_ &&
>             delta < controllerMinFrameDuration * 0.9) {
>                 /*
>                  * Ensure we merge the previous frame's metadata with the current
> --
> 2.39.2
>