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42 lines
1.5 KiB
ReStructuredText
42 lines
1.5 KiB
ReStructuredText
========================
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Linux Framebuffer Driver
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========================
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Overview
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-------------
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The Linux framebuffer (fbdev) is a linux subsystem used to display graphics. It is a hardware-independent API that gives user space software
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access to the framebuffer (the part of a computer's video memory containing a current video frame) using only the Linux kernel's own basic
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facilities and its device file system interface, avoiding the need for libraries that implement video drivers in user space.
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Prerequisites
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-------------
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Your system has a framebuffer device configured (usually under ``/dev/fb0``).
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Configuring the driver
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----------------------
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Enable the framebuffer driver support in lv_conf.h, by cmake compiler define or by KConfig. Additionally you may configure the rendering
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mode.
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.. code:: c
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#define LV_USE_LINUX_FBDEV 1
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#define LV_LINUX_FBDEV_RENDER_MODE LV_DISPLAY_RENDER_MODE_PARTIAL
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Usage
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-----
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To set up a framebuffer-based display, first create a display with ``lv_linux_fbdev_create``. Afterwards set the framebuffer device
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node on the display (usually this is ``/dev/fb0``).
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.. code:: c
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lv_display_t *disp = lv_linux_fbdev_create();
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lv_linux_fbdev_set_file(disp, "/dev/fb0");
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If your screen stays black or only draws partially, you can try enabling direct rendering via ``LV_DISPLAY_RENDER_MODE_DIRECT``. Additionally,
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you can activate a force refresh mode with ``lv_linux_fbdev_set_force_refresh(true)``. This usually has a performance impact though and shouldn't
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be enabled unless really needed.
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