docs/README-raspberrypi.md
author Philipp Wiesemann <philipp.wiesemann@arcor.de>
Thu, 21 May 2015 21:25:14 +0200
changeset 9609 897b25f560d0
parent 9175 ea006adc8372
child 9722 696d7571abcd
permissions -rw-r--r--
Fixed undefined key access in test program.
     1 Raspberry Pi
     2 ================================================================================
     3 
     4 Requirements:
     5 
     6 Raspbian (other Linux distros may work as well).
     7 
     8 ================================================================================
     9  Features
    10 ================================================================================
    11 
    12 * Works without X11
    13 * Hardware accelerated OpenGL ES 2.x
    14 * Sound via ALSA
    15 * Input (mouse/keyboard/joystick) via EVDEV
    16 * Hotplugging of input devices via UDEV
    17 
    18 
    19 ================================================================================
    20  Raspbian Build Dependencies
    21 ================================================================================
    22 
    23 sudo apt-get install libudev-dev libasound2-dev libdbus-1-dev
    24 
    25 You also need the VideoCore binary stuff that ships in /opt/vc for EGL and 
    26 OpenGL ES 2.x, it usually comes pre installed, but in any case:
    27     
    28 sudo apt-get install libraspberrypi0 libraspberrypi-bin libraspberrypi-dev
    29 
    30 ================================================================================
    31  Cross compiling from x86 Linux
    32 ================================================================================
    33 
    34 To cross compile SDL for Raspbian from your desktop machine, you'll need a
    35 Raspbian system root and the cross compilation tools. We'll assume these tools
    36 will be placed in /opt/rpi-tools
    37 
    38     sudo git clone --depth 1 https://github.com/raspberrypi/tools /opt/rpi-tools
    39 
    40 You'll also need a Rasbian binary image.
    41 Get it from: http://downloads.raspberrypi.org/raspbian_latest 
    42 After unzipping, you'll get file with a name like: <date>-wheezy-raspbian.img
    43 Let's assume the sysroot will be built in /opt/rpi-sysroot.
    44 
    45     export SYSROOT=/opt/rpi-sysroot
    46     sudo kpartx -a -v <path_to_raspbian_image>.img
    47     sudo mount -o loop /dev/mapper/loop0p2 /mnt
    48     sudo cp -r /mnt $SYSROOT
    49     sudo apt-get install qemu binfmt-support qemu-user-static
    50     sudo cp /usr/bin/qemu-arm-static $SYSROOT/usr/bin
    51     sudo mount --bind /dev $SYSROOT/dev
    52     sudo mount --bind /proc $SYSROOT/proc
    53     sudo mount --bind /sys $SYSROOT/sys
    54 
    55 Now, before chrooting into the ARM sysroot, you'll need to apply a workaround,
    56 edit $SYSROOT/etc/ld.so.preload and comment out all lines in it.
    57 
    58     sudo chroot $SYSROOT
    59     apt-get install libudev-dev libasound2-dev libdbus-1-dev libraspberrypi0 libraspberrypi-bin libraspberrypi-dev libx11-dev libxext-dev libxrandr-dev libxcursor-dev libxi-dev libxinerama-dev libxxf86vm-dev libxss-dev
    60     exit
    61     sudo umount $SYSROOT/dev
    62     sudo umount $SYSROOT/proc
    63     sudo umount $SYSROOT/sys
    64     sudo umount /mnt
    65     
    66 There's one more fix required, as the libdl.so symlink uses an absolute path 
    67 which doesn't quite work in our setup.
    68 
    69     sudo rm -rf $SYSROOT/usr/lib/arm-linux-gnueabihf/libdl.so
    70     sudo ln -s ../../../lib/arm-linux-gnueabihf/libdl.so.2 $SYSROOT/usr/lib/arm-linux-gnueabihf/libdl.so
    71 
    72 The final step is compiling SDL itself.
    73 
    74     export CC="/opt/rpi-tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-gcc --sysroot=$SYSROOT -I$SYSROOT/opt/vc/include -I$SYSROOT/usr/include -I$SYSROOT/opt/vc/include/interface/vcos/pthreads -I$SYSROOT/opt/vc/include/interface/vmcs_host/linux"
    75     cd <SDL SOURCE>
    76     mkdir -p build;cd build
    77     ../configure --with-sysroot=$SYSROOT --host=arm-raspberry-linux-gnueabihf --prefix=$PWD/rpi-sdl2-installed --disable-pulseaudio --disable-esd
    78     make
    79     make install
    80 
    81 To be able to deploy this to /usr/local in the Raspbian system you need to fix up a few paths:
    82     
    83     perl -w -pi -e "s#$PWD/rpi-sdl2-installed#/usr/local#g;" ./rpi-sdl2-installed/lib/libSDL2.la ./rpi-sdl2-installed/lib/pkgconfig/sdl2.pc ./rpi-sdl2-installed/bin/sdl2-config
    84     
    85 ================================================================================
    86  Apps don't work or poor video/audio performance
    87 ================================================================================
    88 
    89 If you get sound problems, buffer underruns, etc, run "sudo rpi-update" to 
    90 update the RPi's firmware. Note that doing so will fix these problems, but it
    91 will also render the CMA - Dynamic Memory Split functionality useless.
    92 
    93 Also, by default the Raspbian distro configures the GPU RAM at 64MB, this is too
    94 low in general, specially if a 1080p TV is hooked up.
    95 
    96 See here how to configure this setting: http://elinux.org/RPiconfig
    97 
    98 Using a fixed gpu_mem=128 is the best option (specially if you updated the 
    99 firmware, using CMA probably won't work, at least it's the current case).
   100 
   101 ================================================================================
   102  No input
   103 ================================================================================
   104 
   105 Make sure you belong to the "input" group.
   106 
   107     sudo usermod -aG input `whoami`
   108 
   109 ================================================================================
   110  No HDMI Audio
   111 ================================================================================
   112 
   113 If you notice that ALSA works but there's no audio over HDMI, try adding:
   114     
   115     hdmi_drive=2
   116     
   117 to your config.txt file and reboot.
   118 
   119 Reference: http://www.raspberrypi.org/phpBB3/viewtopic.php?t=5062
   120 
   121 ================================================================================
   122  Text Input API support
   123 ================================================================================
   124 
   125 The Text Input API is supported, with translation of scan codes done via the
   126 kernel symbol tables. For this to work, SDL needs access to a valid console.
   127 If you notice there's no SDL_TEXTINPUT message being emitted, double check that
   128 your app has read access to one of the following:
   129     
   130 * /proc/self/fd/0
   131 * /dev/tty
   132 * /dev/tty[0...6]
   133 * /dev/vc/0
   134 * /dev/console
   135 
   136 This is usually not a problem if you run from the physical terminal (as opposed
   137 to running from a pseudo terminal, such as via SSH). If running from a PTS, a 
   138 quick workaround is to run your app as root or add yourself to the tty group,
   139 then re login to the system.
   140 
   141    sudo usermod -aG tty `whoami`
   142     
   143 The keyboard layout used by SDL is the same as the one the kernel uses.
   144 To configure the layout on Raspbian:
   145     
   146     sudo dpkg-reconfigure keyboard-configuration
   147     
   148 To configure the locale, which controls which keys are interpreted as letters,
   149 this determining the CAPS LOCK behavior:
   150 
   151     sudo dpkg-reconfigure locales
   152 
   153 ================================================================================
   154  OpenGL problems
   155 ================================================================================
   156 
   157 If you have desktop OpenGL headers installed at build time in your RPi or cross 
   158 compilation environment, support for it will be built in. However, the chipset 
   159 does not actually have support for it, which causes issues in certain SDL apps 
   160 since the presence of OpenGL support supersedes the ES/ES2 variants.
   161 The workaround is to disable OpenGL at configuration time:
   162 
   163     ./configure --disable-video-opengl
   164 
   165 Or if the application uses the Render functions, you can use the SDL_RENDER_DRIVER
   166 environment variable:
   167 
   168     export SDL_RENDER_DRIVER=opengles2
   169 
   170 ================================================================================
   171  Notes
   172 ================================================================================
   173 
   174 * When launching apps remotely (via SSH), SDL can prevent local keystrokes from
   175   leaking into the console only if it has root privileges. Launching apps locally
   176   does not suffer from this issue.
   177   
   178