[v3,3/3] ipa: libipa: camera_sensor_helper: Add OV2740 black level
diff mbox series

Message ID 20260305-agc-proportional-v3-3-25abc1bfacca@jetm.me
State Superseded
Headers show
Series
  • Simple pipeline: proportional AGC, AWB stats fix, OV2740 black level
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Commit Message

Javier Tia March 5, 2026, 8:10 p.m. UTC 
Set blackLevel_ = 4096 (0x40 at 10-bit) in CameraSensorHelperOv2740.
The OV2740 kernel driver programs BLC target register 0x4003 with 0x40
for the 180 MHz link frequency mode. This matches the same pattern
used by OV5675 and other OmniVision sensors with a 10-bit black level
of 64.

Without this, the Simple pipeline falls back to auto-guessing the
black level, which happens to arrive at the same value but isn't
documented. More importantly, the CameraSensorHelper is the canonical
location for sensor calibration data and is used across all pipeline
handlers, not just Simple.

Suggested-by: Robert Mader <robert.mader@collabora.com>
Signed-off-by: Javier Tia <floss@jetm.me>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
---
 src/ipa/libipa/camera_sensor_helper.cpp | 2 ++
 1 file changed, 2 insertions(+)

Comments

Kieran Bingham March 6, 2026, 11:28 a.m. UTC | #1 
Quoting Javier Tia (2026-03-05 20:10:39)
> Set blackLevel_ = 4096 (0x40 at 10-bit) in CameraSensorHelperOv2740.
> The OV2740 kernel driver programs BLC target register 0x4003 with 0x40
> for the 180 MHz link frequency mode. This matches the same pattern
> used by OV5675 and other OmniVision sensors with a 10-bit black level
> of 64.
> 
> Without this, the Simple pipeline falls back to auto-guessing the
> black level, which happens to arrive at the same value but isn't
> documented. More importantly, the CameraSensorHelper is the canonical
> location for sensor calibration data and is used across all pipeline
> handlers, not just Simple.
> 
> Suggested-by: Robert Mader <robert.mader@collabora.com>
> Signed-off-by: Javier Tia <floss@jetm.me>
> Reviewed-by: Milan Zamazal <mzamazal@redhat.com>

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

> ---
>  src/ipa/libipa/camera_sensor_helper.cpp | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/src/ipa/libipa/camera_sensor_helper.cpp b/src/ipa/libipa/camera_sensor_helper.cpp
> index e3e3e535..3028197e 100644
> --- a/src/ipa/libipa/camera_sensor_helper.cpp
> +++ b/src/ipa/libipa/camera_sensor_helper.cpp
> @@ -672,6 +672,8 @@ class CameraSensorHelperOv2740 : public CameraSensorHelper
>  public:
>         CameraSensorHelperOv2740()
>         {
> +               /* From Linux kernel driver: 0x40 at 10bits. */
> +               blackLevel_ = 4096;
>                 gain_ = AnalogueGainLinear{ 1, 0, 0, 128 };
>         }
>  };
> 
> -- 
> 2.53.0
>

Patch
diff mbox series 

diff --git a/src/ipa/libipa/camera_sensor_helper.cpp b/src/ipa/libipa/camera_sensor_helper.cpp
index e3e3e535..3028197e 100644
--- a/src/ipa/libipa/camera_sensor_helper.cpp
+++ b/src/ipa/libipa/camera_sensor_helper.cpp
@@ -672,6 +672,8 @@  class CameraSensorHelperOv2740 : public CameraSensorHelper
 public:
 	CameraSensorHelperOv2740()
 	{
+		/* From Linux kernel driver: 0x40 at 10bits. */
+		blackLevel_ = 4096;
 		gain_ = AnalogueGainLinear{ 1, 0, 0, 128 };
 	}
 };