From 43180e12bac330ab872e24c2a896a15df6e6fa92 Mon Sep 17 00:00:00 2001 From: Bryan O'Donoghue Date: Tue, 6 Jan 2026 17:00:55 +0000 Subject: [PATCH] libcamera: software_isp: lut: Skip calculation lookup tables if gpuIspEnabled is true On my reference platform Qualcomm RB5 sm8520 the qcam application CPU occupancy drops from ~100% to about 95% of a single core so this one change sheds aprox 5% CPU usage. Reviewed-by: Milan Zamazal Tested-by: Robert Mader Tested-by: Hans de Goede # ThinkPad T14s gen 6 (arm64) ov02c10 + X1c gen 12 ov08x40 Tested-by: Kieran Bingham # Lenovo X13s Signed-off-by: Bryan O'Donoghue Signed-off-by: Kieran Bingham --- src/ipa/simple/algorithms/lut.cpp | 67 ++++++++++++++++--------------- 1 file changed, 35 insertions(+), 32 deletions(-) diff --git a/src/ipa/simple/algorithms/lut.cpp b/src/ipa/simple/algorithms/lut.cpp index 7d015ac8..7418daa1 100644 --- a/src/ipa/simple/algorithms/lut.cpp +++ b/src/ipa/simple/algorithms/lut.cpp @@ -56,33 +56,34 @@ void Lut::queueRequest(typename Module::Context &context, void Lut::updateGammaTable(IPAContext &context) { - auto &gammaTable = context.activeState.gamma.gammaTable; const auto blackLevel = context.activeState.blc.level; - const unsigned int blackIndex = blackLevel * gammaTable.size() / 256; const auto contrast = context.activeState.knobs.contrast.value_or(1.0); /* Convert 0..2 to 0..infinity; avoid actual inifinity at tan(pi/2) */ double contrastExp = tan(std::clamp(contrast * M_PI_4, 0.0, M_PI_2 - 0.00001)); - const float divisor = gammaTable.size() - blackIndex - 1.0; - for (unsigned int i = blackIndex; i < gammaTable.size(); i++) { - double normalized = (i - blackIndex) / divisor; - /* Convert 0..2 to 0..infinity; avoid actual inifinity at tan(pi/2) */ - /* Apply simple S-curve */ - if (normalized < 0.5) - normalized = 0.5 * std::pow(normalized / 0.5, contrastExp); - else - normalized = 1.0 - 0.5 * std::pow((1.0 - normalized) / 0.5, contrastExp); - gammaTable[i] = UINT8_MAX * - std::pow(normalized, context.configuration.gamma); + if (!context.gpuIspEnabled) { + auto &gammaTable = context.activeState.gamma.gammaTable; + const unsigned int blackIndex = blackLevel * gammaTable.size() / 256; + const float divisor = gammaTable.size() - blackIndex - 1.0; + for (unsigned int i = blackIndex; i < gammaTable.size(); i++) { + double normalized = (i - blackIndex) / divisor; + /* Apply simple S-curve */ + if (normalized < 0.5) + normalized = 0.5 * std::pow(normalized / 0.5, contrastExp); + else + normalized = 1.0 - 0.5 * std::pow((1.0 - normalized) / 0.5, contrastExp); + gammaTable[i] = UINT8_MAX * + std::pow(normalized, context.configuration.gamma); + } + /* + * Due to CCM operations, the table lookup may reach indices below the black + * level. Let's set the table values below black level to the minimum + * non-black value to prevent problems when the minimum value is + * significantly non-zero (for example, when the image should be all grey). + */ + std::fill(gammaTable.begin(), gammaTable.begin() + blackIndex, + gammaTable[blackIndex]); } - /* - * Due to CCM operations, the table lookup may reach indices below the black - * level. Let's set the table values below black level to the minimum - * non-black value to prevent problems when the minimum value is - * significantly non-zero (for example, when the image should be all grey). - */ - std::fill(gammaTable.begin(), gammaTable.begin() + blackIndex, - gammaTable[blackIndex]); context.activeState.gamma.blackLevel = blackLevel; context.activeState.gamma.contrastExp = contrastExp; @@ -135,17 +136,19 @@ void Lut::prepare(IPAContext &context, auto &green = params->greenCcm; auto &blue = params->blueCcm; params->ccm = ccm; - for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++) { - red[i].r = ccmValue(i, ccm[0][0]); - red[i].g = ccmValue(i, ccm[1][0]); - red[i].b = ccmValue(i, ccm[2][0]); - green[i].r = ccmValue(i, ccm[0][1]); - green[i].g = ccmValue(i, ccm[1][1]); - green[i].b = ccmValue(i, ccm[2][1]); - blue[i].r = ccmValue(i, ccm[0][2]); - blue[i].g = ccmValue(i, ccm[1][2]); - blue[i].b = ccmValue(i, ccm[2][2]); - params->gammaLut[i] = gammaTable[i / div]; + if (!context.gpuIspEnabled) { + for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++) { + red[i].r = ccmValue(i, ccm[0][0]); + red[i].g = ccmValue(i, ccm[1][0]); + red[i].b = ccmValue(i, ccm[2][0]); + green[i].r = ccmValue(i, ccm[0][1]); + green[i].g = ccmValue(i, ccm[1][1]); + green[i].b = ccmValue(i, ccm[2][1]); + blue[i].r = ccmValue(i, ccm[0][2]); + blue[i].g = ccmValue(i, ccm[1][2]); + blue[i].b = ccmValue(i, ccm[2][2]); + params->gammaLut[i] = gammaTable[i / div]; + } } }