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From: Sakari Ailus <sakari.ailus@iki.fi>
To: Balakrishnan Sambath <balakrishnan.s@microchip.com>
Cc: linux-media@vger.kernel.org, eugen.hristev@linaro.org,
	mchehab@kernel.org, hverkuil@kernel.org,
	nicolas.ferre@microchip.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 11/15] media: microchip-isc: add per-channel gamma LUT controls
Date: Fri, 15 May 2026 13:26:20 +0300	[thread overview]
Message-ID: <agb0zAmeEILM4JJy@valkosipuli.retiisi.eu> (raw)
In-Reply-To: <20260512154339.210444-12-balakrishnan.s@microchip.com>

Hi Balakrishnan,

Thanks for the set.

On Tue, May 12, 2026 at 09:13:35PM +0530, Balakrishnan Sambath wrote:
> Add 64-entry gamma LUT controls for R/G/B channels. Setting any LUT
> overrides V4L2_CID_GAMMA; writing V4L2_CID_GAMMA restores presets.
> Supports SAMA7G5 bipartite encoding.

I'd say hardware this complicated should use parameter buffers like other
similar hardware does. The reasoning is that the userspace gets an
interface that allows passing all relevant parameters to the driver at one
go, with a reasonable expectation on which frame it can be applied to.
Controls provide neither of these.

On top of this, the control framework, while useful for high level
configuration parameters, introduces quite a bit of validation overhead
that can affect performance while the effect of a bad parameter value is
simply bad output and the software setting these values is purpose-built so
it can already take the ranges and steps into account.

-- 
Kind regards,

Sakari Ailus

  reply	other threads:[~2026-05-15 10:26 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-09 15:52 [PATCH 00/18] media: microchip-isc: Color correction and histogram stats Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 01/18] media: platform: microchip: set maximum resolution for sam9x7 Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 02/18] media: platform: microchip: Include DPC modules flags in pipeline Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 03/18] media: microchip-isc: Enable GDC and CBC module flags for RGB formats Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 04/18] media: microchip-isc: Improve histogram calculation with outlier rejection Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 05/18] media: microchip-isc: Use channel averages for Grey World AWB Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 06/18] media: microchip-isc: Add range based black level correction Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 07/18] media: platform: microchip: Extend gamma table and control range Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 08/18] media: platform: microchip: Add new histogram submodule Balamanikandan Gunasundar
2025-11-10  8:41   ` Hans Verkuil
2025-11-10  8:55   ` Hans Verkuil
2025-10-09 15:52 ` [PATCH 09/18] media: microchip-isc: Register and unregister statistics device Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 10/18] media: microchip-isc: Always enable histogram for all RAW formats Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 11/18] media: microchip-isc: expose hue and saturation as v4l2 controls Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 12/18] media: microchip-isc: Rename CBC to CBHS Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 13/18] media: microchip-isc: Store histogram data of all channels Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 14/18] media: microchip-isc: fix histogram state initialization order Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 15/18] media: microchip-isc: decouple histogram cycling from AWB mode Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 16/18] media: microchip-isc: enable userspace histogram statistics export Balamanikandan Gunasundar
2025-10-09 15:52 ` [PATCH 17/18] media: videodev2.h, v4l2-ioctl: Add microchip statistics format Balamanikandan Gunasundar
2025-11-10  8:49   ` Hans Verkuil
2025-10-09 15:52 ` [PATCH 18/18] media: microchip-isc: expose color correction registers as v4l2 controls Balamanikandan Gunasundar
2025-10-09 20:11 ` [PATCH 00/18] media: microchip-isc: Color correction and histogram stats Eugen Hristev
2025-10-10  8:21   ` Kieran Bingham
2025-10-10  8:27     ` Laurent Pinchart
2025-10-15  6:05     ` Balamanikandan.Gunasundar
2025-10-15  6:45       ` Balamanikandan.Gunasundar
2025-10-15  6:33     ` Balamanikandan.Gunasundar
2025-10-15  5:26   ` Balamanikandan.Gunasundar
2025-11-10  9:01 ` Hans Verkuil
2025-11-10  9:26 ` Hans Verkuil
2026-05-12 15:43 ` [PATCH v2 00/15] media: microchip-isc: fixes and enhancements Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 01/15] media: microchip-isc: fix SBGGR10 Bayer pattern Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 02/15] media: microchip-isc: mask WB offset and gain register fields Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 03/15] media: microchip-isc: fix race condition on stream stop Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 04/15] media: microchip-isc: fix PM runtime leak in AWB work handler Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 05/15] media: microchip-isc: add driver documentation Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 06/15] media: microchip-isc: set SAM9X7 maximum resolution to 2560x1920 Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 07/15] media: microchip-isc: configure DPC and pipeline for SAMA7G5 Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 08/15] media: microchip-isc: add gamma 1.8 and 2.4 correction curves Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 09/15] media: microchip-isc: add SAMA7G5 hue and saturation controls Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 10/15] media: microchip-isc: expose color correction matrix as V4L2 controls Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 11/15] media: microchip-isc: add per-channel gamma LUT controls Balakrishnan Sambath
2026-05-15 10:26     ` Sakari Ailus [this message]
2026-05-12 15:43   ` [PATCH v2 12/15] media: microchip-isc: reset pipeline state on kernel AWB enable Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 13/15] media: microchip-isc: use weighted averages for Grey World AWB Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 14/15] media: microchip-isc: smooth AWB gains with EMA filter Balakrishnan Sambath
2026-05-12 15:43   ` [PATCH v2 15/15] media: microchip-isc: scale DPC black level to sensor bit depth Balakrishnan Sambath
2026-05-13  7:17   ` [PATCH v3 00/15] media: microchip-isc: fixes and enhancements Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 01/15] media: microchip-isc: fix SBGGR10 Bayer pattern Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 02/15] media: microchip-isc: mask WB offset and gain register fields Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 03/15] media: microchip-isc: fix race condition on stream stop Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 04/15] media: microchip-isc: fix PM runtime leak in AWB work handler Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 05/15] media: microchip-isc: add driver documentation Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 06/15] media: microchip-isc: set SAM9X7 maximum resolution to 2560x1920 Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 07/15] media: microchip-isc: configure DPC and pipeline for SAMA7G5 Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 08/15] media: microchip-isc: add gamma 1.8 and 2.4 correction curves Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 09/15] media: microchip-isc: add SAMA7G5 hue and saturation controls Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 10/15] media: microchip-isc: expose color correction matrix as V4L2 controls Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 11/15] media: microchip-isc: add per-channel gamma LUT controls Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 12/15] media: microchip-isc: reset pipeline state on kernel AWB enable Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 13/15] media: microchip-isc: use weighted averages for Grey World AWB Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 14/15] media: microchip-isc: smooth AWB gains with EMA filter Balakrishnan Sambath
2026-05-13  7:17     ` [PATCH v3 15/15] media: microchip-isc: scale DPC black level to sensor bit depth Balakrishnan Sambath
2026-05-15 10:27     ` [PATCH v3 00/15] media: microchip-isc: fixes and enhancements Sakari Ailus

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