[{"id":35958,"web_url":"https://patchwork.libcamera.org/comment/35958/","msgid":"<85qzvwmfob.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","date":"2025-09-24T08:13:24","subject":"Re: [PATCH 4/5] ipa: software_isp: AGC: Only use integers for\n\texposure calculations","submitter":{"id":177,"url":"https://patchwork.libcamera.org/api/people/177/","name":"Milan Zamazal","email":"mzamazal@redhat.com"},"content":"Hi Hans,\n\nthank you for the patch.\n\nHans de Goede writes:\n\n> Exposure is an integer, instead of re-using the \"double next\" used\n> for again calculations, doing intermediate calculations with double\n> precision, use a local next variable of an integer type.\n\nUsing separate locals is cleaner anyway.\n\nReviewed-by: Milan Zamazal \n\n> Signed-off-by: Hans de Goede \n> ---\n> src/ipa/simple/algorithms/agc.cpp | 9 ++++-----\n> 1 file changed, 4 insertions(+), 5 deletions(-)\n>\n> diff --git a/src/ipa/simple/algorithms/agc.cpp b/src/ipa/simple/algorithms/agc.cpp\n> index 230616e62..cdde56ba2 100644\n> --- a/src/ipa/simple/algorithms/agc.cpp\n> +++ b/src/ipa/simple/algorithms/agc.cpp\n> @@ -51,19 +51,18 @@ void Agc::updateExposure(IPAContext &context, IPAFrameContext &frameContext, dou\n> \tstatic constexpr uint8_t kExpNumeratorUp = kExpDenominator + 1;\n> \tstatic constexpr uint8_t kExpNumeratorDown = kExpDenominator - 1;\n> \n> -\tdouble next;\n> \tint32_t &exposure = frameContext.sensor.exposure;\n> \tdouble &again = frameContext.sensor.gain;\n> \n> \tif (exposureMSV < kExposureOptimal - kExposureSatisfactory) {\n> \t\tif (exposure < context.configuration.agc.exposureMax) {\n> -\t\t\tnext = exposure * kExpNumeratorUp / kExpDenominator;\n> +\t\t\tint32_t next = exposure * kExpNumeratorUp / kExpDenominator;\n> \t\t\tif (next - exposure < 1)\n> \t\t\t\texposure += 1;\n> \t\t\telse\n> \t\t\t\texposure = next;\n> \t\t} else {\n> -\t\t\tnext = again * kExpNumeratorUp / kExpDenominator;\n> +\t\t\tdouble next = again * kExpNumeratorUp / kExpDenominator;\n> \t\t\tif (next - again < context.configuration.agc.againMinStep)\n> \t\t\t\tagain += context.configuration.agc.againMinStep;\n> \t\t\telse\n> @@ -73,13 +72,13 @@ void Agc::updateExposure(IPAContext &context, IPAFrameContext &frameContext, dou\n> \n> \tif (exposureMSV > kExposureOptimal + kExposureSatisfactory) {\n> \t\tif (again > context.configuration.agc.againDef) {\n> -\t\t\tnext = again * kExpNumeratorDown / kExpDenominator;\n> +\t\t\tdouble next = again * kExpNumeratorDown / kExpDenominator;\n> \t\t\tif (again - next < context.configuration.agc.againMinStep)\n> \t\t\t\tagain -= context.configuration.agc.againMinStep;\n> \t\t\telse\n> \t\t\t\tagain = next;\n> \t\t} else {\n> -\t\t\tnext = exposure * kExpNumeratorDown / kExpDenominator;\n> +\t\t\tint32_t next = exposure * kExpNumeratorDown / kExpDenominator;\n> \t\t\tif (exposure - next < 1)\n> \t\t\t\texposure -= 1;\n> \t\t\telse","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 7114DBDB1C\n\tfor ;\n\tWed, 24 Sep 2025 08:15:37 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id F33246B5F9;\n\tWed, 24 Sep 2025 10:15:35 +0200 (CEST)","from us-smtp-delivery-124.mimecast.com\n\t(us-smtp-delivery-124.mimecast.com [170.10.133.124])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 8A46D6B5C2\n\tfor ;\n\tWed, 24 Sep 2025 10:13:35 +0200 (CEST)","from mail-wm1-f72.google.com (mail-wm1-f72.google.com\n\t[209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS\n\t(version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id\n\tus-mta-392-r3rHCEodPSeohlzUwxe-Iw-1; Wed, 24 Sep 2025 04:13:27 -0400","by 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2002:a05:600c:3b11:b0:45d:e4ff:b642 with SMTP id\n\t5b1f17b1804b1-46e1dac5378mr53446045e9.25.1758701605735; \n\tWed, 24 Sep 2025 01:13:25 -0700 (PDT)","by 2002:a05:600c:3b11:b0:45d:e4ff:b642 with SMTP id\n\t5b1f17b1804b1-46e1dac5378mr53445765e9.25.1758701605304; \n\tWed, 24 Sep 2025 01:13:25 -0700 (PDT)"],"X-Google-Smtp-Source":"AGHT+IFGZp8k6qZIYfsFGQm3X2jGKgaCVsJUvHxHMD5s0Xch1/gs+RND0GIZWNTdxKT/qfN9UnlzkQ==","From":"Milan Zamazal ","To":"Hans de Goede ","Cc":"libcamera-devel@lists.libcamera.org","Subject":"Re: [PATCH 4/5] ipa: software_isp: AGC: Only use integers for\n\texposure calculations","In-Reply-To":"<20250923190657.21453-5-hansg@kernel.org> (Hans de Goede's\n\tmessage of \"Tue, 23 Sep 2025 21:06:56 +0200\")","References":"<20250923190657.21453-1-hansg@kernel.org>\n\t<20250923190657.21453-5-hansg@kernel.org>","Date":"Wed, 24 Sep 2025 10:13:24 +0200","Message-ID":"<85qzvwmfob.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","User-Agent":"Gnus/5.13 (Gnus v5.13)","MIME-Version":"1.0","X-Mimecast-Spam-Score":"0","X-Mimecast-MFC-PROC-ID":"CPL56CmnwonWhwDMjxB-62HFlcLw4IWASdNf2tc1zWE_1758701606","X-Mimecast-Originator":"redhat.com","Content-Type":"text/plain","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":35968,"web_url":"https://patchwork.libcamera.org/comment/35968/","msgid":"<175879474062.88644.6168530041117078525@isaac-ThinkPad-T16-Gen-2>","date":"2025-09-25T10:05:40","subject":"Re: [PATCH 4/5] ipa: software_isp: AGC: Only use integers for\n\texposure calculations","submitter":{"id":215,"url":"https://patchwork.libcamera.org/api/people/215/","name":"Isaac Scott","email":"isaac.scott@ideasonboard.com"},"content":"Hi Hans,\n\nThank you for the patch!\n\nQuoting Hans de Goede (2025-09-23 20:06:56)\n> Exposure is an integer, instead of re-using the \"double next\" used\n> for again calculations, doing intermediate calculations with double\n> precision, use a local next variable of an integer type.\n> \n> Signed-off-by: Hans de Goede \n> ---\n> src/ipa/simple/algorithms/agc.cpp | 9 ++++-----\n> 1 file changed, 4 insertions(+), 5 deletions(-)\n> \n> diff --git a/src/ipa/simple/algorithms/agc.cpp b/src/ipa/simple/algorithms/agc.cpp\n> index 230616e62..cdde56ba2 100644\n> --- a/src/ipa/simple/algorithms/agc.cpp\n> +++ b/src/ipa/simple/algorithms/agc.cpp\n> @@ -51,19 +51,18 @@ void Agc::updateExposure(IPAContext &context, IPAFrameContext &frameContext, dou\n> static constexpr uint8_t kExpNumeratorUp = kExpDenominator + 1;\n> static constexpr uint8_t kExpNumeratorDown = kExpDenominator - 1;\n> \n> - double next;\n> int32_t &exposure = frameContext.sensor.exposure;\n> double &again = frameContext.sensor.gain;\n> \n> if (exposureMSV < kExposureOptimal - kExposureSatisfactory) {\n> if (exposure < context.configuration.agc.exposureMax) {\n> - next = exposure * kExpNumeratorUp / kExpDenominator;\n> + int32_t next = exposure * kExpNumeratorUp / kExpDenominator;\n> if (next - exposure < 1)\n> exposure += 1;\n> else\n> exposure = next;\n> } else {\n> - next = again * kExpNumeratorUp / kExpDenominator;\n> + double next = again * kExpNumeratorUp / kExpDenominator;\n\nReviewed-by: Isaac Scott \n\nBest wishes,\nIsaac\n\n> if (next - again < context.configuration.agc.againMinStep)\n> again += context.configuration.agc.againMinStep;\n> else\n> @@ -73,13 +72,13 @@ void Agc::updateExposure(IPAContext &context, IPAFrameContext &frameContext, dou\n> \n> if (exposureMSV > kExposureOptimal + kExposureSatisfactory) {\n> if (again > context.configuration.agc.againDef) {\n> - next = again * kExpNumeratorDown / kExpDenominator;\n> + double next = again * kExpNumeratorDown / kExpDenominator;\n> if (again - next < context.configuration.agc.againMinStep)\n> again -= context.configuration.agc.againMinStep;\n> else\n> again = next;\n> } else {\n> - next = exposure * kExpNumeratorDown / kExpDenominator;\n> + int32_t next = exposure * kExpNumeratorDown / kExpDenominator;\n> if (exposure - next < 1)\n> exposure -= 1;\n> else\n> -- \n> 2.51.0\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 27EE4C328C\n\tfor ;\n\tThu, 25 Sep 2025 10:05:47 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 3127F6B5F3;\n\tThu, 25 Sep 2025 12:05:46 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 6762869318\n\tfor ;\n\tThu, 25 Sep 2025 12:05:44 +0200 (CEST)","from 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charset=\"utf-8\"","MIME-Version":"1.0","Content-Transfer-Encoding":"quoted-printable","In-Reply-To":"<20250923190657.21453-5-hansg@kernel.org>","References":"<20250923190657.21453-1-hansg@kernel.org>\n\t<20250923190657.21453-5-hansg@kernel.org>","Subject":"Re: [PATCH 4/5] ipa: software_isp: AGC: Only use integers for\n\texposure calculations","From":"Isaac Scott ","Cc":"Hans de Goede ","To":"Hans de Goede , libcamera-devel@lists.libcamera.org","Date":"Thu, 25 Sep 2025 11:05:40 +0100","Message-ID":"<175879474062.88644.6168530041117078525@isaac-ThinkPad-T16-Gen-2>","User-Agent":"alot/0.10","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]