[{"id":39817,"web_url":"https://patchwork.libcamera.org/comment/39817/","msgid":"","date":"2026-07-24T10:05:43","subject":"Re: [PATCH] libcamera: egl: Cache probed EGLDisplay to avoid\n\tredundant init/teardown","submitter":{"id":216,"url":"https://patchwork.libcamera.org/api/people/216/","name":"Barnabás Pőcze","email":"barnabas.pocze@ideasonboard.com"},"content":"2026. 07. 24. 3:43 keltezéssel, qi.hou@oss.nxp.com írta:\n> From: Qi Hou \n> \n> isAvailable() previously called probeDisplay() which ran eglBindAPI(),\n> eglGetPlatformDisplay() and eglInitialize(), then immediately terminated\n> the display with eglTerminate(). When SoftwareIsp subsequently called\n> initEGLContext(), probeDisplay() repeated a full initialisation sequence.\n> \n> Avoid this double init/teardown by caching the EGLDisplay handle inside\n> probeDisplay() using static parameters. The first call initialises EGL\n> and stores the result, all later calls return the cached handle\n> without reinitialising.\n> \n> isAvailable() is simplified to return probeDisplay() != EGL_NO_DISPLAY\n> and no longer calls eglTerminate(), because the cached display should\n> be live for reuse by initEGLContext().\n> ---\n> src/libcamera/egl.cpp | 31 +++++++++++++++++--------------\n> 1 file changed, 17 insertions(+), 14 deletions(-)\n> \n> diff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp\n> index 7ec7a654d..f5200ee76 100644\n> --- a/src/libcamera/egl.cpp\n> +++ b/src/libcamera/egl.cpp\n> @@ -301,46 +301,49 @@ void eGL::createTexture2D(eGLImage &eglImage, void *data)\n> \n> EGLDisplay eGL::probeDisplay()\n> {\n> -\tEGLDisplay display;\n> +\tstatic EGLDisplay cachedDisplay = EGL_NO_DISPLAY;\n> +\tstatic bool probed = false;\n\nI'm not a fan of adding more mutable global state. As an alternative:\n * modify `eGL` to take the EGLDisplay in its constructor\n and adjust `initEGLContext()` to not retrieve the display\n * adjust `DebayerEGL` accordingly\n * adjust `SoftwareISP` to call `probeDisplay()` and forward the result\n\nHere is a prototype of the idea:\n\ndiff --git a/include/libcamera/internal/egl.h b/include/libcamera/internal/egl.h\nindex 1e31d490bd..7ef1ca0d93 100644\n--- a/include/libcamera/internal/egl.h\n+++ b/include/libcamera/internal/egl.h\n@@ -99,11 +99,11 @@ private:\n class eGL\n {\n public:\n-\teGL();\n+\teGL(EGLDisplay display);\n \t~eGL();\n \n \tint initEGLContext();\n-\tstatic bool isAvailable();\n+\tstatic EGLDisplay probeDisplay();\n \n \tint createInputDMABufTexture2D(eGLImage &eglImage, int fd);\n \tint createOutputDMABufTexture2D(eGLImage &eglImage, int fd);\n@@ -137,7 +137,6 @@ private:\n \tEGLContext context_ = EGL_NO_CONTEXT;\n \tEGLSurface surface_ = EGL_NO_SURFACE;\n \n-\tstatic EGLDisplay probeDisplay();\n \tint compileShader(int shaderType, GLuint &shaderId, Span shaderData,\n \t\t\t Span shaderEnv);\n \ndiff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp\nindex 7ec7a654da..3d1a15493a 100644\n--- a/src/libcamera/egl.cpp\n+++ b/src/libcamera/egl.cpp\n@@ -64,12 +64,15 @@ LOG_DEFINE_CATEGORY(eGL)\n \n /**\n * \\brief Construct an EGL helper\n+ * \\param[in] display The EGL display to use\n *\n * Creates an eGL instance with uninitialised context. Call initEGLContext()\n- * to set up the EGL display, context, and load extension functions.\n+ * to set up the EGL context, and load extension functions.\n */\n-eGL::eGL()\n+eGL::eGL(EGLDisplay display)\n+\t: display_(display)\n {\n+\tASSERT(display_ != EGL_NO_DISPLAY);\n }\n \n /**\n@@ -299,6 +302,13 @@ void eGL::createTexture2D(eGLImage &eglImage, void *data)\n \tglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);\n }\n \n+/**\n+ * \\brief Try to create an EGL display for surfaceless rendering\n+ *\n+ * Tries to create an EGL display for surfaceless rendering.\n+ *\n+ * \\return A EGL display handle if successfull, otherwise \\a EGL_NO_DISPLAY\n+ */\n EGLDisplay eGL::probeDisplay()\n {\n \tEGLDisplay display;\n@@ -325,24 +335,6 @@ EGLDisplay eGL::probeDisplay()\n \treturn display;\n }\n \n-/**\n- * \\brief Probe whether EGL surfaceless rendering is available\n- *\n- * Checks if an EGL surfaceless display can be obtained and initialised.\n- * The display is immediately terminated so that no resources are leaked.\n- *\n- * \\return True if EGL surfaceless rendering is available, false otherwise\n- */\n-bool eGL::isAvailable()\n-{\n-\tEGLDisplay display = probeDisplay();\n-\tif (display == EGL_NO_DISPLAY)\n-\t\treturn false;\n-\n-\teglTerminate(display);\n-\treturn true;\n-}\n-\n /**\n * \\brief Update a 2D texture already created\n * \\param[in,out] eglImage EGL image to associate with the texture\n@@ -403,12 +395,6 @@ int eGL::initEGLContext()\n \tEGLint numConfigs;\n \tEGLConfig config;\n \n-\tdisplay_ = probeDisplay();\n-\tif (display_ == EGL_NO_DISPLAY) {\n-\t\tLOG(eGL, Error) << \"Unable to probe display\";\n-\t\tgoto fail;\n-\t}\n-\n \tLOG(eGL, Info) << \"EGL: EGL_VERSION: \" << eglQueryString(display_, EGL_VERSION);\n \tLOG(eGL, Info) << \"EGL: EGL_VENDOR: \" << eglQueryString(display_, EGL_VENDOR);\n \tLOG(eGL, Info) << \"EGL: EGL_CLIENT_APIS: \" << eglQueryString(display_, EGL_CLIENT_APIS);\ndiff --git a/src/libcamera/software_isp/debayer_egl.cpp b/src/libcamera/software_isp/debayer_egl.cpp\nindex dd20412194..20b478b1c3 100644\n--- a/src/libcamera/software_isp/debayer_egl.cpp\n+++ b/src/libcamera/software_isp/debayer_egl.cpp\n@@ -40,9 +40,10 @@ namespace libcamera {\n * \\brief Construct a DebayerEGL object\n * \\param[in] stats Statistics processing object\n * \\param[in] cm The camera manager\n+ * \\param[in] display The EGL display to use\n */\n-DebayerEGL::DebayerEGL(std::unique_ptr stats, const CameraManager &cm)\n-\t: Debayer(cm), stats_(std::move(stats))\n+DebayerEGL::DebayerEGL(std::unique_ptr stats, const CameraManager &cm, EGLDisplay display)\n+\t: Debayer(cm), stats_(std::move(stats)), egl_(display)\n {\n }\n \ndiff --git a/src/libcamera/software_isp/debayer_egl.h b/src/libcamera/software_isp/debayer_egl.h\nindex e613639f5c..30e51a4773 100644\n--- a/src/libcamera/software_isp/debayer_egl.h\n+++ b/src/libcamera/software_isp/debayer_egl.h\n@@ -40,7 +40,7 @@ class CameraManager;\n class DebayerEGL : public Debayer\n {\n public:\n-\tDebayerEGL(std::unique_ptr stats, const CameraManager &cm);\n+\tDebayerEGL(std::unique_ptr stats, const CameraManager &cm, EGLDisplay display);\n \t~DebayerEGL();\n \n \tint configure(const StreamConfiguration &inputCfg,\ndiff --git a/src/libcamera/software_isp/software_isp.cpp b/src/libcamera/software_isp/software_isp.cpp\nindex c73a16ce0a..c7165771c6 100644\n--- a/src/libcamera/software_isp/software_isp.cpp\n+++ b/src/libcamera/software_isp/software_isp.cpp\n@@ -120,8 +120,9 @@ SoftwareIsp::SoftwareIsp(PipelineHandler *pipe, const CameraSensor *sensor,\n \t}\n \n \tif (!softISPMode || softISPMode == \"gpu\") {\n-\t\tif (eGL::isAvailable()) {\n-\t\t\tdebayer_ = std::make_unique(std::move(stats), cm);\n+\t\tauto display = eGL::probeDisplay();\n+\t\tif (display != EGL_NO_DISPLAY) {\n+\t\t\tdebayer_ = std::make_unique(std::move(stats), cm, display);\n \t\t} else {\n \t\t\tLOG(SoftwareIsp, Info)\n \t\t\t\t<< \"EGL not available, falling back to CPU debayer\";\n\n> +\n> +\tif (probed)\n> +\t\treturn cachedDisplay;\n> +\n> +\tprobed = true;\n> \n> \tif (!eglBindAPI(EGL_OPENGL_ES_API)) {\n> \t\tLOG(eGL, Info) << \"API bind fail\";\n> \t\treturn EGL_NO_DISPLAY;\n> \t}\n> \n> -\tdisplay = eglGetPlatformDisplay(EGL_PLATFORM_SURFACELESS_MESA,\n> -\t\t\t\t\tEGL_DEFAULT_DISPLAY,\n> -\t\t\t\t\tnullptr);\n> +\tcachedDisplay = eglGetPlatformDisplay(EGL_PLATFORM_SURFACELESS_MESA,\n> +\t\t\t\t\t EGL_DEFAULT_DISPLAY,\n> +\t\t\t\t\t nullptr);\n> \n> -\tif (display == EGL_NO_DISPLAY) {\n> +\tif (cachedDisplay == EGL_NO_DISPLAY) {\n> \t\tLOG(eGL, Info) << \"Unable to get EGL display\";\n> \t\treturn EGL_NO_DISPLAY;\n> \t}\n> \n> -\tif (eglInitialize(display, nullptr, nullptr) != EGL_TRUE) {\n> +\tif (eglInitialize(cachedDisplay, nullptr, nullptr) != EGL_TRUE) {\n> \t\tLOG(eGL, Error) << \"eglInitialize fail\";\n> +\t\tcachedDisplay = EGL_NO_DISPLAY;\n> \t\treturn EGL_NO_DISPLAY;\n> \t}\n> \n> -\treturn display;\n> +\treturn cachedDisplay;\n> }\n> \n> /**\n> * \\brief Probe whether EGL surfaceless rendering is available\n> *\n> * Checks if an EGL surfaceless display can be obtained and initialised.\n> - * The display is immediately terminated so that no resources are leaked.\n> + * The result is cached so that a subsequent call to initEGLContext() reuses\n> + * the already-initialised display without a redundant init/teardown cycle.\n> *\n> * \\return True if EGL surfaceless rendering is available, false otherwise\n> */\n> bool eGL::isAvailable()\n> {\n> -\tEGLDisplay display = probeDisplay();\n> -\tif (display == EGL_NO_DISPLAY)\n> -\t\treturn false;\n> -\n> -\teglTerminate(display);\n> -\treturn true;\n> +\treturn probeDisplay() != EGL_NO_DISPLAY;\n> }\n> \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 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t=1784887486;\n\tbh=gtBwz++dqEMqVpaKolIwmxoMTMIrMH3+R3ZO9usovrA=;\n\th=Date:Subject:To:Cc:References:From:In-Reply-To:From;\n\tb=MRCp4nmR2SU16gtCfcygH5Wt80x0oP8pFMfHy2Q6Z8HBXHDEjr27He0zevT8vqpAt\n\tnEQZ+VaDqmKQ4pBF0U26Wz9ZgJXxpf1HXuMxvUlDZXg8fsT06rSHKL0RCF1FOa7NAO\n\tvEcMLii6f08ILrHJCWh4/GE8NjESSQTLVTGlSdcc=","Message-ID":"","Date":"Fri, 24 Jul 2026 12:05:43 +0200","MIME-Version":"1.0","User-Agent":"Mozilla Thunderbird","Subject":"Re: [PATCH] libcamera: egl: Cache probed EGLDisplay to avoid\n\tredundant init/teardown","To":"qi.hou@oss.nxp.com, libcamera-devel@lists.libcamera.org","Cc":"jared.hu@nxp.com, qi.hou@nxp.com, julien.vuillaumier@nxp.com","References":"<20260724014338.1850939-1-qi.hou@oss.nxp.com>","From":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","Content-Language":"en-US, hu-HU","In-Reply-To":"<20260724014338.1850939-1-qi.hou@oss.nxp.com>","Content-Type":"text/plain; charset=UTF-8; format=flowed","Content-Transfer-Encoding":"8bit","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":39860,"web_url":"https://patchwork.libcamera.org/comment/39860/","msgid":"","date":"2026-07-27T06:44:51","subject":"RE: [PATCH] libcamera: egl: Cache probed EGLDisplay to avoid\n\tredundant init/teardown","submitter":{"id":455,"url":"https://patchwork.libcamera.org/api/people/455/","name":"Qi Hou (OSS)","email":"qi.hou@oss.nxp.com"},"content":"Hi Barnabás Pőcze,\n\nThanks for your detailed review. I have sent out v2 named as \"[v2] libcamera: egl: Pass EGLDisplay to eGL constructor to avoid double init\".\n\nRegards,\nQi Hou\n\n-----Original Message-----\nFrom: Barnabás Pőcze \nSent: Friday, July 24, 2026 6:06 PM\nTo: Qi Hou (OSS) ; libcamera-devel@lists.libcamera.org\nCc: Jared Hu ; Qi Hou ; Julien Vuillaumier \nSubject: Re: [PATCH] libcamera: egl: Cache probed EGLDisplay to avoid redundant init/teardown\n\n2026. 07. 24. 3:43 keltezéssel, qi.hou@oss.nxp.com írta:\n> From: Qi Hou \n> \n> isAvailable() previously called probeDisplay() which ran eglBindAPI(),\n> eglGetPlatformDisplay() and eglInitialize(), then immediately \n> terminated the display with eglTerminate(). When SoftwareIsp \n> subsequently called initEGLContext(), probeDisplay() repeated a full initialisation sequence.\n> \n> Avoid this double init/teardown by caching the EGLDisplay handle \n> inside\n> probeDisplay() using static parameters. The first call initialises EGL \n> and stores the result, all later calls return the cached handle \n> without reinitialising.\n> \n> isAvailable() is simplified to return probeDisplay() != EGL_NO_DISPLAY \n> and no longer calls eglTerminate(), because the cached display should \n> be live for reuse by initEGLContext().\n> ---\n> src/libcamera/egl.cpp | 31 +++++++++++++++++--------------\n> 1 file changed, 17 insertions(+), 14 deletions(-)\n> \n> diff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp index \n> 7ec7a654d..f5200ee76 100644\n> --- a/src/libcamera/egl.cpp\n> +++ b/src/libcamera/egl.cpp\n> @@ -301,46 +301,49 @@ void eGL::createTexture2D(eGLImage &eglImage, \n> void *data)\n> \n> EGLDisplay eGL::probeDisplay()\n> {\n> -\tEGLDisplay display;\n> +\tstatic EGLDisplay cachedDisplay = EGL_NO_DISPLAY;\n> +\tstatic bool probed = false;\n\nI'm not a fan of adding more mutable global state. As an alternative:\n * modify `eGL` to take the EGLDisplay in its constructor\n and adjust `initEGLContext()` to not retrieve the display\n * adjust `DebayerEGL` accordingly\n * adjust `SoftwareISP` to call `probeDisplay()` and forward the result\n\nHere is a prototype of the idea:\n\ndiff --git a/include/libcamera/internal/egl.h b/include/libcamera/internal/egl.h\nindex 1e31d490bd..7ef1ca0d93 100644\n--- a/include/libcamera/internal/egl.h\n+++ b/include/libcamera/internal/egl.h\n@@ -99,11 +99,11 @@ private:\n class eGL\n {\n public:\n-\teGL();\n+\teGL(EGLDisplay display);\n \t~eGL();\n \n \tint initEGLContext();\n-\tstatic bool isAvailable();\n+\tstatic EGLDisplay probeDisplay();\n \n \tint createInputDMABufTexture2D(eGLImage &eglImage, int fd);\n \tint createOutputDMABufTexture2D(eGLImage &eglImage, int fd); @@ -137,7 +137,6 @@ private:\n \tEGLContext context_ = EGL_NO_CONTEXT;\n \tEGLSurface surface_ = EGL_NO_SURFACE;\n \n-\tstatic EGLDisplay probeDisplay();\n \tint compileShader(int shaderType, GLuint &shaderId, Span shaderData,\n \t\t\t Span shaderEnv);\n \ndiff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp index 7ec7a654da..3d1a15493a 100644\n--- a/src/libcamera/egl.cpp\n+++ b/src/libcamera/egl.cpp\n@@ -64,12 +64,15 @@ LOG_DEFINE_CATEGORY(eGL)\n \n /**\n * \\brief Construct an EGL helper\n+ * \\param[in] display The EGL display to use\n *\n * Creates an eGL instance with uninitialised context. Call initEGLContext()\n- * to set up the EGL display, context, and load extension functions.\n+ * to set up the EGL context, and load extension functions.\n */\n-eGL::eGL()\n+eGL::eGL(EGLDisplay display)\n+\t: display_(display)\n {\n+\tASSERT(display_ != EGL_NO_DISPLAY);\n }\n \n /**\n@@ -299,6 +302,13 @@ void eGL::createTexture2D(eGLImage &eglImage, void *data)\n \tglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);\n }\n \n+/**\n+ * \\brief Try to create an EGL display for surfaceless rendering\n+ *\n+ * Tries to create an EGL display for surfaceless rendering.\n+ *\n+ * \\return A EGL display handle if successfull, otherwise \\a \n+EGL_NO_DISPLAY */\n EGLDisplay eGL::probeDisplay()\n {\n \tEGLDisplay display;\n@@ -325,24 +335,6 @@ EGLDisplay eGL::probeDisplay()\n \treturn display;\n }\n \n-/**\n- * \\brief Probe whether EGL surfaceless rendering is available\n- *\n- * Checks if an EGL surfaceless display can be obtained and initialised.\n- * The display is immediately terminated so that no resources are leaked.\n- *\n- * \\return True if EGL surfaceless rendering is available, false otherwise\n- */\n-bool eGL::isAvailable()\n-{\n-\tEGLDisplay display = probeDisplay();\n-\tif (display == EGL_NO_DISPLAY)\n-\t\treturn false;\n-\n-\teglTerminate(display);\n-\treturn true;\n-}\n-\n /**\n * \\brief Update a 2D texture already created\n * \\param[in,out] eglImage EGL image to associate with the texture @@ -403,12 +395,6 @@ int eGL::initEGLContext()\n \tEGLint numConfigs;\n \tEGLConfig config;\n \n-\tdisplay_ = probeDisplay();\n-\tif (display_ == EGL_NO_DISPLAY) {\n-\t\tLOG(eGL, Error) << \"Unable to probe display\";\n-\t\tgoto fail;\n-\t}\n-\n \tLOG(eGL, Info) << \"EGL: EGL_VERSION: \" << eglQueryString(display_, EGL_VERSION);\n \tLOG(eGL, Info) << \"EGL: EGL_VENDOR: \" << eglQueryString(display_, EGL_VENDOR);\n \tLOG(eGL, Info) << \"EGL: EGL_CLIENT_APIS: \" << eglQueryString(display_, EGL_CLIENT_APIS); diff --git a/src/libcamera/software_isp/debayer_egl.cpp b/src/libcamera/software_isp/debayer_egl.cpp\nindex dd20412194..20b478b1c3 100644\n--- a/src/libcamera/software_isp/debayer_egl.cpp\n+++ b/src/libcamera/software_isp/debayer_egl.cpp\n@@ -40,9 +40,10 @@ namespace libcamera {\n * \\brief Construct a DebayerEGL object\n * \\param[in] stats Statistics processing object\n * \\param[in] cm The camera manager\n+ * \\param[in] display The EGL display to use\n */\n-DebayerEGL::DebayerEGL(std::unique_ptr stats, const CameraManager &cm)\n-\t: Debayer(cm), stats_(std::move(stats))\n+DebayerEGL::DebayerEGL(std::unique_ptr stats, const CameraManager &cm, EGLDisplay display)\n+\t: Debayer(cm), stats_(std::move(stats)), egl_(display)\n {\n }\n \ndiff --git a/src/libcamera/software_isp/debayer_egl.h b/src/libcamera/software_isp/debayer_egl.h\nindex e613639f5c..30e51a4773 100644\n--- a/src/libcamera/software_isp/debayer_egl.h\n+++ b/src/libcamera/software_isp/debayer_egl.h\n@@ -40,7 +40,7 @@ class CameraManager;\n class DebayerEGL : public Debayer\n {\n public:\n-\tDebayerEGL(std::unique_ptr stats, const CameraManager &cm);\n+\tDebayerEGL(std::unique_ptr stats, const CameraManager &cm, \n+EGLDisplay display);\n \t~DebayerEGL();\n \n \tint configure(const StreamConfiguration &inputCfg, diff --git a/src/libcamera/software_isp/software_isp.cpp b/src/libcamera/software_isp/software_isp.cpp\nindex c73a16ce0a..c7165771c6 100644\n--- a/src/libcamera/software_isp/software_isp.cpp\n+++ b/src/libcamera/software_isp/software_isp.cpp\n@@ -120,8 +120,9 @@ SoftwareIsp::SoftwareIsp(PipelineHandler *pipe, const CameraSensor *sensor,\n \t}\n \n \tif (!softISPMode || softISPMode == \"gpu\") {\n-\t\tif (eGL::isAvailable()) {\n-\t\t\tdebayer_ = std::make_unique(std::move(stats), cm);\n+\t\tauto display = eGL::probeDisplay();\n+\t\tif (display != EGL_NO_DISPLAY) {\n+\t\t\tdebayer_ = std::make_unique(std::move(stats), cm, \n+display);\n \t\t} else {\n \t\t\tLOG(SoftwareIsp, Info)\n \t\t\t\t<< \"EGL not available, falling back to CPU debayer\";\n\n> +\n> +\tif (probed)\n> +\t\treturn cachedDisplay;\n> +\n> +\tprobed = true;\n> \n> \tif (!eglBindAPI(EGL_OPENGL_ES_API)) {\n> \t\tLOG(eGL, Info) << \"API bind fail\";\n> \t\treturn EGL_NO_DISPLAY;\n> \t}\n> \n> -\tdisplay = eglGetPlatformDisplay(EGL_PLATFORM_SURFACELESS_MESA,\n> -\t\t\t\t\tEGL_DEFAULT_DISPLAY,\n> -\t\t\t\t\tnullptr);\n> +\tcachedDisplay = eglGetPlatformDisplay(EGL_PLATFORM_SURFACELESS_MESA,\n> +\t\t\t\t\t EGL_DEFAULT_DISPLAY,\n> +\t\t\t\t\t nullptr);\n> \n> -\tif (display == EGL_NO_DISPLAY) {\n> +\tif (cachedDisplay == EGL_NO_DISPLAY) {\n> \t\tLOG(eGL, Info) << \"Unable to get EGL display\";\n> \t\treturn EGL_NO_DISPLAY;\n> \t}\n> \n> -\tif (eglInitialize(display, nullptr, nullptr) != EGL_TRUE) {\n> +\tif (eglInitialize(cachedDisplay, nullptr, nullptr) != EGL_TRUE) {\n> \t\tLOG(eGL, Error) << \"eglInitialize fail\";\n> +\t\tcachedDisplay = EGL_NO_DISPLAY;\n> \t\treturn EGL_NO_DISPLAY;\n> \t}\n> \n> -\treturn display;\n> +\treturn cachedDisplay;\n> }\n> \n> /**\n> * \\brief Probe whether EGL surfaceless rendering is available\n> *\n> * Checks if an EGL surfaceless display can be obtained and initialised.\n> - * The display is immediately terminated so that no resources are leaked.\n> + * The result is cached so that a subsequent call to initEGLContext() \n> + reuses\n> + * the already-initialised display without a redundant init/teardown cycle.\n> *\n> * \\return True if EGL surfaceless rendering is available, false otherwise\n> */\n> bool eGL::isAvailable()\n> {\n> -\tEGLDisplay display = probeDisplay();\n> -\tif (display == EGL_NO_DISPLAY)\n> -\t\treturn false;\n> -\n> -\teglTerminate(display);\n> -\treturn true;\n> +\treturn probeDisplay() != EGL_NO_DISPLAY;\n> }\n> \n> /**","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com 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