[{"id":37752,"web_url":"https://patchwork.libcamera.org/comment/37752/","msgid":"<20260119205113.GB18962@pendragon.ideasonboard.com>","date":"2026-01-19T20:51:13","subject":"Re: [PATCH v2 1/2] egl: Use the Mesa surfaceless platform instead of\n\tGBM","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"On Mon, Jan 19, 2026 at 09:28:34PM +0100, Robert Mader wrote:\n> Which appears to be a better fit for the use-case at hand:\n\nMesa surfaceless platform appears to be ...\n\n> 1. Like GBM it is Mesa specific, so no change in supported setups is\n> expected. If ever required, a fallback to the generic device platform\n> could be added on top.\n> 2. It leaves the complexity of selecting a renderer device to the\n> driver, reducing code and dependencies.\n> 3. It allows to use llvmpipe / software drivers without dri device,\n> which can be useful on CI or debugging (with LIBGL_ALWAYS_SOFTWARE=1).\n> \n> Signed-off-by: Robert Mader \n> Reviewed-by: Bryan O'Donoghue \n> Tested-by: Bryan O'Donoghue # sm8250/rb5, x1e/Dell Insprion14p\n> Reviewed-by: Milan Zamazal \n> Tested-by: Milan Zamazal # TI AM69\n> Tested-by: Barnabás Pőcze # ThinkPad X1 Yoga Gen 7 + ov2740\n> ---\n> include/libcamera/internal/egl.h | 4 +---\n> src/libcamera/egl.cpp | 12 +++++-------\n> src/libcamera/software_isp/debayer_egl.cpp | 7 ++-----\n> src/libcamera/software_isp/debayer_egl.h | 1 -\n> 4 files changed, 8 insertions(+), 16 deletions(-)\n> \n> diff --git a/include/libcamera/internal/egl.h b/include/libcamera/internal/egl.h\n> index f007f448a..630345ea7 100644\n> --- a/include/libcamera/internal/egl.h\n> +++ b/include/libcamera/internal/egl.h\n> @@ -16,8 +16,6 @@\n> #include \n> #include \n> \n> -#include \"libcamera/internal/gbm.h\"\n> -\n> #define EGL_EGLEXT_PROTOTYPES\n> #include \n> #include \n> @@ -96,7 +94,7 @@ public:\n> \teGL();\n> \t~eGL();\n> \n> -\tint initEGLContext(GBM *gbmContext);\n> +\tint initEGLContext();\n> \n> \tint createInputDMABufTexture2D(eGLImage &eglImage, int fd);\n> \tint createOutputDMABufTexture2D(eGLImage &eglImage, int fd);\n> diff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp\n> index da563ee09..7ff1b5ea2 100644\n> --- a/src/libcamera/egl.cpp\n> +++ b/src/libcamera/egl.cpp\n> @@ -256,24 +256,22 @@ void eGL::createTexture2D(eGLImage &eglImage, GLint format, uint32_t width, uint\n> \n> /**\n> * \\brief Initialise the EGL context\n> - * \\param[in] gbmContext Pointer to initialised GBM context\n> *\n> - * Sets up the EGL display from the GBM device, creates an OpenGL ES 2.0\n> - * context, and retrieves function pointers for required extensions\n> - * including:\n> + * Sets up the EGL display, creates an OpenGL ES 2.0 context, and retrieves\n> + * function pointers for required extensions including:\n> * - eglCreateImageKHR / eglDestroyImageKHR\n> * - glEGLImageTargetTexture2DOES\n> *\n> * \\return 0 on success, or -ENODEV on failure\n> */\n> -int eGL::initEGLContext(GBM *gbmContext)\n> +int eGL::initEGLContext()\n> {\n> \tEGLint configAttribs[] = {\n> \t\tEGL_RED_SIZE, 8,\n> \t\tEGL_GREEN_SIZE, 8,\n> \t\tEGL_BLUE_SIZE, 8,\n> \t\tEGL_ALPHA_SIZE, 8,\n> -\t\tEGL_SURFACE_TYPE, EGL_WINDOW_BIT,\n> +\t\tEGL_SURFACE_TYPE, EGL_PBUFFER_BIT,\n> \t\tEGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,\n> \t\tEGL_NONE\n> \t};\n> @@ -291,7 +289,7 @@ int eGL::initEGLContext(GBM *gbmContext)\n> \t\tgoto fail;\n> \t}\n> \n> -\tdisplay_ = eglGetDisplay(gbmContext->device());\n> +\tdisplay_ = eglGetPlatformDisplay(EGL_PLATFORM_SURFACELESS_MESA, nullptr, nullptr);\n\n\tdisplay_ = eglGetPlatformDisplay(EGL_PLATFORM_SURFACELESS_MESA, nullptr,\n\t\t\t\t\t nullptr);\n\nBut according to\nhttps://registry.khronos.org/EGL/extensions/MESA/EGL_MESA_platform_surfaceless.txt\nthe native_display parameter must be EGL_DEFAULT_DISPLAY, so this would\nbe\n\n\tdisplay_ = 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> \t\tLOG(eGL, Error) << \"Unable to get EGL display\";\n> \t\tgoto fail;\n> diff --git a/src/libcamera/software_isp/debayer_egl.cpp b/src/libcamera/software_isp/debayer_egl.cpp\n> index 9693d7252..c85c7d6cd 100644\n> --- a/src/libcamera/software_isp/debayer_egl.cpp\n> +++ b/src/libcamera/software_isp/debayer_egl.cpp\n> @@ -142,7 +142,7 @@ int DebayerEGL::initBayerShaders(PixelFormat inputFormat, PixelFormat outputForm\n> \n> \t/*\n> \t * Tell shaders how to re-order output taking account of how the\n> -\t * pixels are actually stored by GBM\n> +\t * pixels are actually stored by EGL\n\nWhile at it let's improve the comment formatting:\n\n\t * Tell shaders how to re-order output taking account of how the pixels\n\t * are actually stored by EGL.\n\nReviewed-by: Laurent Pinchart \n\n> \t */\n> \tswitch (outputFormat) {\n> \tcase formats::ARGB8888:\n> @@ -586,10 +586,7 @@ int DebayerEGL::start()\n> {\n> \tGLint maxTextureImageUnits;\n> \n> -\tif (gbmSurface_.createDevice())\n> -\t\treturn -ENODEV;\n> -\n> -\tif (egl_.initEGLContext(&gbmSurface_))\n> +\tif (egl_.initEGLContext())\n> \t\treturn -ENODEV;\n> \n> \tglGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &maxTextureImageUnits);\n> diff --git a/src/libcamera/software_isp/debayer_egl.h b/src/libcamera/software_isp/debayer_egl.h\n> index a5033bc63..cfbaf8e9d 100644\n> --- a/src/libcamera/software_isp/debayer_egl.h\n> +++ b/src/libcamera/software_isp/debayer_egl.h\n> @@ -113,7 +113,6 @@ private:\n> \tRectangle window_;\n> \tstd::unique_ptr stats_;\n> \teGL egl_;\n> -\tGBM gbmSurface_;\n> \tuint32_t width_;\n> \tuint32_t height_;\n> \tGLint glFormat_;","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from 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c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1768855865;\n\tbh=OFHNcPCb2TyTRpygrnUqfDl9mL4MYyFbl8zJ6HB7ZGU=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=wXLmGJvhkZ3CQYurRLZ+Mq2J/dglEEvKSabhYsjydIuZ/z0Ey1qVzd6Jsw8Nus317\n\trhOQmAe8BOrp07TfyS6gIQmUl9DF6H4m9695uyIb+1X4uQD3r9RPb7OgOf1J4jUyLg\n\tXIYObawxtGQ81FVv74AKcxC/wqYzGf3uCY1b0S5w=","Date":"Mon, 19 Jan 2026 22:51:13 +0200","From":"Laurent Pinchart ","To":"Robert Mader ","Cc":"libcamera-devel@lists.libcamera.org, Bryan O'Donoghue\n\t, Milan Zamazal ,\n\t=?utf-8?b?QmFybmFiw6FzIFDFkWN6?= =?utf-8?q?e?=\n\t","Subject":"Re: [PATCH v2 1/2] egl: Use the Mesa surfaceless platform instead of\n\tGBM","Message-ID":"<20260119205113.GB18962@pendragon.ideasonboard.com>","References":"<20260119202835.372125-1-robert.mader@collabora.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","Content-Transfer-Encoding":"8bit","In-Reply-To":"<20260119202835.372125-1-robert.mader@collabora.com>","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":37757,"web_url":"https://patchwork.libcamera.org/comment/37757/","msgid":"","date":"2026-01-20T12:24:28","subject":"Re: [PATCH v2 1/2] egl: Use the Mesa surfaceless platform instead of\n\tGBM","submitter":{"id":140,"url":"https://patchwork.libcamera.org/api/people/140/","name":"Robert Mader","email":"robert.mader@collabora.com"},"content":"All done in v3, thanks!\n\nOn 19.01.26 21:51, Laurent Pinchart wrote:\n> On Mon, Jan 19, 2026 at 09:28:34PM +0100, Robert Mader wrote:\n>> Which appears to be a better fit for the use-case at hand:\n> Mesa surfaceless platform appears to be ...\n>\n>> 1. Like GBM it is Mesa specific, so no change in supported setups is\n>> expected. If ever required, a fallback to the generic device platform\n>> could be added on top.\n>> 2. It leaves the complexity of selecting a renderer device to the\n>> driver, reducing code and dependencies.\n>> 3. It allows to use llvmpipe / software drivers without dri device,\n>> which can be useful on CI or debugging (with LIBGL_ALWAYS_SOFTWARE=1).\n>>\n>> Signed-off-by: Robert Mader \n>> Reviewed-by: Bryan O'Donoghue \n>> Tested-by: Bryan O'Donoghue # sm8250/rb5, x1e/Dell Insprion14p\n>> Reviewed-by: Milan Zamazal \n>> Tested-by: Milan Zamazal # TI AM69\n>> Tested-by: Barnabás Pőcze # ThinkPad X1 Yoga Gen 7 + ov2740\n>> ---\n>> include/libcamera/internal/egl.h | 4 +---\n>> src/libcamera/egl.cpp | 12 +++++-------\n>> src/libcamera/software_isp/debayer_egl.cpp | 7 ++-----\n>> src/libcamera/software_isp/debayer_egl.h | 1 -\n>> 4 files changed, 8 insertions(+), 16 deletions(-)\n>>\n>> diff --git a/include/libcamera/internal/egl.h b/include/libcamera/internal/egl.h\n>> index f007f448a..630345ea7 100644\n>> --- a/include/libcamera/internal/egl.h\n>> +++ b/include/libcamera/internal/egl.h\n>> @@ -16,8 +16,6 @@\n>> #include \n>> #include \n>> \n>> -#include \"libcamera/internal/gbm.h\"\n>> -\n>> #define EGL_EGLEXT_PROTOTYPES\n>> #include \n>> #include \n>> @@ -96,7 +94,7 @@ public:\n>> \teGL();\n>> \t~eGL();\n>> \n>> -\tint initEGLContext(GBM *gbmContext);\n>> +\tint initEGLContext();\n>> \n>> \tint createInputDMABufTexture2D(eGLImage &eglImage, int fd);\n>> \tint createOutputDMABufTexture2D(eGLImage &eglImage, int fd);\n>> diff --git a/src/libcamera/egl.cpp b/src/libcamera/egl.cpp\n>> index da563ee09..7ff1b5ea2 100644\n>> --- a/src/libcamera/egl.cpp\n>> +++ b/src/libcamera/egl.cpp\n>> @@ -256,24 +256,22 @@ void eGL::createTexture2D(eGLImage &eglImage, GLint format, uint32_t width, uint\n>> \n>> /**\n>> * \\brief Initialise the EGL context\n>> - * \\param[in] gbmContext Pointer to initialised GBM context\n>> *\n>> - * Sets up the EGL display from the GBM device, creates an OpenGL ES 2.0\n>> - * context, and retrieves function pointers for required extensions\n>> - * including:\n>> + * Sets up the EGL display, creates an OpenGL ES 2.0 context, and retrieves\n>> + * function pointers for required extensions including:\n>> * - eglCreateImageKHR / eglDestroyImageKHR\n>> * - glEGLImageTargetTexture2DOES\n>> *\n>> * \\return 0 on success, or -ENODEV on failure\n>> */\n>> -int eGL::initEGLContext(GBM *gbmContext)\n>> +int eGL::initEGLContext()\n>> {\n>> \tEGLint configAttribs[] = {\n>> \t\tEGL_RED_SIZE, 8,\n>> \t\tEGL_GREEN_SIZE, 8,\n>> \t\tEGL_BLUE_SIZE, 8,\n>> \t\tEGL_ALPHA_SIZE, 8,\n>> -\t\tEGL_SURFACE_TYPE, EGL_WINDOW_BIT,\n>> +\t\tEGL_SURFACE_TYPE, EGL_PBUFFER_BIT,\n>> \t\tEGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,\n>> \t\tEGL_NONE\n>> \t};\n>> @@ -291,7 +289,7 @@ int eGL::initEGLContext(GBM *gbmContext)\n>> \t\tgoto fail;\n>> \t}\n>> \n>> -\tdisplay_ = eglGetDisplay(gbmContext->device());\n>> +\tdisplay_ = eglGetPlatformDisplay(EGL_PLATFORM_SURFACELESS_MESA, nullptr, nullptr);\n> \tdisplay_ = eglGetPlatformDisplay(EGL_PLATFORM_SURFACELESS_MESA, nullptr,\n> \t\t\t\t\t nullptr);\n>\n> But according to\n> https://registry.khronos.org/EGL/extensions/MESA/EGL_MESA_platform_surfaceless.txt\n> the native_display parameter must be EGL_DEFAULT_DISPLAY, so this would\n> be\n>\n> \tdisplay_ = 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>> \t\tLOG(eGL, Error) << \"Unable to get EGL display\";\n>> \t\tgoto fail;\n>> diff --git a/src/libcamera/software_isp/debayer_egl.cpp b/src/libcamera/software_isp/debayer_egl.cpp\n>> index 9693d7252..c85c7d6cd 100644\n>> --- a/src/libcamera/software_isp/debayer_egl.cpp\n>> +++ b/src/libcamera/software_isp/debayer_egl.cpp\n>> @@ -142,7 +142,7 @@ int DebayerEGL::initBayerShaders(PixelFormat inputFormat, PixelFormat outputForm\n>> \n>> \t/*\n>> \t * Tell shaders how to re-order output taking account of how the\n>> -\t * pixels are actually stored by GBM\n>> +\t * pixels are actually stored by EGL\n> While at it let's improve the comment formatting:\n>\n> \t * Tell shaders how to re-order output taking account of how the pixels\n> \t * are actually stored by EGL.\n>\n> Reviewed-by: Laurent Pinchart \n>\n>> \t */\n>> \tswitch (outputFormat) {\n>> \tcase formats::ARGB8888:\n>> @@ -586,10 +586,7 @@ int DebayerEGL::start()\n>> {\n>> \tGLint maxTextureImageUnits;\n>> \n>> -\tif (gbmSurface_.createDevice())\n>> -\t\treturn -ENODEV;\n>> -\n>> -\tif (egl_.initEGLContext(&gbmSurface_))\n>> +\tif (egl_.initEGLContext())\n>> \t\treturn -ENODEV;\n>> \n>> \tglGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &maxTextureImageUnits);\n>> diff --git a/src/libcamera/software_isp/debayer_egl.h b/src/libcamera/software_isp/debayer_egl.h\n>> index a5033bc63..cfbaf8e9d 100644\n>> --- a/src/libcamera/software_isp/debayer_egl.h\n>> +++ b/src/libcamera/software_isp/debayer_egl.h\n>> @@ -113,7 +113,6 @@ private:\n>> \tRectangle window_;\n>> \tstd::unique_ptr stats_;\n>> \teGL egl_;\n>> -\tGBM gbmSurface_;\n>> \tuint32_t width_;\n>> \tuint32_t height_;\n>> \tGLint glFormat_;","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 1A52ABDCBF\n\tfor ;\n\tTue, 20 Jan 2026 12:24:42 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id C0C1961FC7;\n\tTue, 20 Jan 2026 13:24:41 +0100 (CET)","from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com\n\t[136.143.188.112])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 3BE3261A35\n\tfor ;\n\tTue, 20 Jan 2026 13:24:40 +0100 (CET)","by mx.zohomail.com with SMTPS id 1768911873972821.8352613290051;\n\tTue, 20 Jan 2026 04:24:33 -0800 (PST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=collabora.com\n\theader.i=robert.mader@collabora.com 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=?utf-8?q?e?=\n\t","References":"<20260119202835.372125-1-robert.mader@collabora.com>\n\t<20260119205113.GB18962@pendragon.ideasonboard.com>","Content-Language":"en-US, de-DE","From":"Robert Mader ","In-Reply-To":"<20260119205113.GB18962@pendragon.ideasonboard.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\" "}}]