Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. There is no picture in lcd
Qt 6.11 is out! See what's new in the release blog

There is no picture in lcd

Scheduled Pinned Locked Moved Solved General and Desktop
23 Posts 3 Posters 6.0k Views 1 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • J junzhang

    Hi,
    l cross compiling qt for armv7, and then write an example to test, the code below

    int main(int argc, char *argv[])
    {
     QApplication a(argc, argv);
        MainWindow w;
        w.setStyleSheet("background-color:blue;");
        w.show();
    }
    but there is no picture in lcd, l change the code below
    int main(int argc, char *argv[])
    {
    	int fbFd = 0;
    	const char *devfile = "/dev/fb0";
    	fbFd = open(devfile, O_RDWR);
    	if (ioctl(fbFd, FBIOGET_VSCREENINFO, &vinfo) == -1) {
    		perror("Error reading variable information");
    		exit(3);
        }
        if (fbFd == -1) {
    		perror("Error: cannot open framebuffer device");
    		exit(1);
        }
    	if(ioctl(fbFd, FBIOPAN_DISPLAY, &vinfo)!= 0)
        {
            return -1;
        }
    	if(ioctl(fbFd, FBIOPAN_DISPLAY, &vinfo)!= 0)
        {
            return -1;
        }
    	
        QApplication a(argc, argv);
        MainWindow w;
    
        w.setStyleSheet("background-color:blue;");
        w.show();
    	if (ioctl(fbFd, FBIOGET_VSCREENINFO, &vinfo) == -1) {
    		perror("Error reading variable information");
    		exit(3);
        }
    	if (ioctl(fbFd, FBIOGET_FSCREENINFO, &finfo) == -1) {
    		perror("Error reading fixed information");
    		exit(2);
        }
    	if(ioctl(fbFd, FBIOPAN_DISPLAY, &vinfo)!= 0)
        {
            return -1;
        }
        return a.exec();
    }
    

    after compile and then download, the lcd can show picture,
    so, why we must add this code? whether there is wrong for my cross compiling?

    Edit: p3c0

    D Offline
    D Offline
    Devopia53
    wrote on last edited by
    #3

    @junzhang

    Hi.

    What is the platform plugin are you setting?
    If it is not setting, the QT_QPA_PLATFORM environment variable parameter can be used to setting or the -platform command-line can be used with the same syntax.

    Like this(for example):
    QT_QPA_PLATFORM=linuxfb:fb=/dev/fb0
    or
    ./yourapp -platform linuxfb:fb=/dev/fb0

    1 Reply Last reply
    0
    • J Offline
      J Offline
      junzhang
      wrote on last edited by
      #4

      Dear Devopia53,
      how can l set my platform plugin?
      my profile is below:

      export TSLIB_ROOT=/usr/local/tslib
      export TSLIB_TSDEVICE=/dev/event0
      export TSLIB_FBDEVICE=/dev/fb0
      export TSLIB_PLUGINDIR=/usr/local/tslib/lib/ts
      export TSLIB_CONSOLEDEVICE=none
      export TSLIB_CONFFILE=/usr/local/tslib/etc/ts.conf
      export POINTERCAL_FILE=/etc/pointercal
      export TSLIB_CALIBFILE=/etc/pointercal
      #export QWS_SIZE=128x128
      export QWS_MOUSE_PROTO=Tslib:/dev/event0
      export QTDIR=/usr/local/qt
      export QPEDIR=/usr/local/qt
      export QWS_DISPLAY=LinuxFb:/dev/fb0
      export LD_LIBRARY_PATH=$TSLIB_ROOT/lib:$QTDIR/lib:$LD_LIBRARY_PATH
      export QT_QWS_FONTDIR=$QTDIR/lib/fonts
      export LD_LIBRARY_PATH=/usr/local/qtlib/lib:$LD_LIBRARY_PATH
      export PATH PS1 OPIEDIR QPEDIR QTDIR EDITOR TERM

      1 Reply Last reply
      0
      • SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on last edited by
        #5

        Using Qt 4?

        Interested in AI ? www.idiap.ch
        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

        J 1 Reply Last reply
        0
        • SGaistS SGaist

          Using Qt 4?

          J Offline
          J Offline
          junzhang
          wrote on last edited by
          #6

          @SGaist
          yes, qt4.8.5

          1 Reply Last reply
          0
          • SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #7

            Did you check the permissions on the frame buffer device ?

            On a side note, if locked on Qt 4, the you should go with 4.8.7 which is the latest and last version of the Qt 4 series. Otherwise, you should go with Qt 5.

            Interested in AI ? www.idiap.ch
            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

            J 1 Reply Last reply
            0
            • SGaistS SGaist

              Did you check the permissions on the frame buffer device ?

              On a side note, if locked on Qt 4, the you should go with 4.8.7 which is the latest and last version of the Qt 4 series. Otherwise, you should go with Qt 5.

              J Offline
              J Offline
              junzhang
              wrote on last edited by
              #8

              @SGaist
              here is my cross compile config:
              sudo ./configure --prefix=/usr/local/qt4.8.5-arm -opensource -release -shared -Declarative -importdir /opt/imports -fast -no-largefile -qt-sql-sqlite -qt3support -exceptions -xmlpatterns -no-glib -no-phonon -no-mmx -no-3dnow -no-sse -no-sse2 -svg -no-webkit -qt-zlib -qt-libtiff -qt-libpng -qt-libjpeg -make libs -make tools -nomake examples -nomake docs -nomake demo -no-nis -no-cups -iconv -no-dbus -xplatform qws/linux-arm-g++ -embedded arm -little-endian -qt-freetype -depths 16,24,32 -qt-gfx-linuxfb -qt-gfx-transformed -qt-gfx-multiscreen -no-gfx-vnc -no-gfx-qvfb -qt-kbd-linuxinput -no-kbd-qvfb -armfpa -no-mouse-qvfb -qt-mouse-linuxtp -qt-mouse-tslib -DQT_QLOCALE_USES_FCVT -DQT_NO_QWS_CURSOR -no-pch -I/usr/local/tslib/include -L/usr/local/tslib/lib -confirm-license

              1 Reply Last reply
              0
              • SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #9

                That doesn't answer my question about the permissions of /dev/fb0 on your target.

                On a side note, never develop nor build as root. If something goes wrong there's no restriction at what can be destroyed on your system.

                Interested in AI ? www.idiap.ch
                Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                J 1 Reply Last reply
                1
                • SGaistS SGaist

                  That doesn't answer my question about the permissions of /dev/fb0 on your target.

                  On a side note, never develop nor build as root. If something goes wrong there's no restriction at what can be destroyed on your system.

                  J Offline
                  J Offline
                  junzhang
                  wrote on last edited by
                  #10

                  @SGaist
                  / # ls /dev/fb0 -l
                  crw-rw---- 1 root root 29, 0 Jan 1 00:00 /dev/fb0

                  when l use Qt/qt/qt-everywhere-opensource-src-4.8.5/examples/qws/framebuffer to test, it's ok,
                  your mean it's maybe to compile use "sudo"?
                  l will re-compile it with no "sudo".

                  1 Reply Last reply
                  0
                  • SGaistS Offline
                    SGaistS Offline
                    SGaist
                    Lifetime Qt Champion
                    wrote on last edited by
                    #11

                    How are you calling your application on the command line ?

                    Interested in AI ? www.idiap.ch
                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                    J 2 Replies Last reply
                    0
                    • SGaistS SGaist

                      How are you calling your application on the command line ?

                      J Offline
                      J Offline
                      junzhang
                      wrote on last edited by
                      #12

                      @SGaist
                      ./test_demo -qws

                      1 Reply Last reply
                      0
                      • SGaistS SGaist

                        How are you calling your application on the command line ?

                        J Offline
                        J Offline
                        junzhang
                        wrote on last edited by
                        #13

                        @SGaist
                        l use normal user to cross compile qt5.7.0, it's still unshow anything unless l add "ioctl(fbFd, FBIOGET_FSCREENINFO, &finfo)".and it just to show one frame,
                        my cross compile steps is below:

                        1. download tslib1.4.tar.gz$ ./autogen.sh
                          $ tar zxvf tslib1.4.tar.gz
                          $ ./configure CC=arm-none-linux-gnueabihf-gcc CXX=arm-none-linux-gnueabihf-g++ --prefix=/usr/local/tslib --host=arm-none-linux-gnueabihf ac_cv_func_malloc_0_nonnull=yes
                          $make
                          $sudo make install

                        2. download qt-everywhere-opensource-src-5.7.0.tar.gz
                          2.1: tar zxvf qt-everywhere-opensource-src-5.7.0.tar.gz
                          2.2: vim qt-everywhere-opensource-src-5.7.0/qtbase/mkspecs/linux-arm-gnueabi-g++/qmake.conf

                           include(../common/linux.conf)
                          + QT_QPA_DEFAULT_PLATFORM = linux #eglfs 
                          +QMAKE_CFLAGS_RELEASE += -O2 -march=armv7-a
                          + QMAKE_CXXFLAGS_RELEASE += -O2 -march=armv7-a
                          

                          arm-linux-geneabi-xxx change to arm-none-linux-geneabi-xxx
                          2.3: vim build.sh

                          #!/bin/sh
                          ./configure
                          -v
                          -prefix /opt/qt5.7.0
                          -release
                          -opensource
                          -make libs
                          -xplatform linux-arm-gnueabi-g++
                          -optimized-qmake
                          -pch
                          -qt-sql-sqlite
                          -qt-libjpeg
                          -qt-zlib
                          -no-opengl
                          -skip qt3d
                          -skip qtcanvas3d
                          -skip qtpurchasing
                          -no-sse2
                          -no-openssl
                          -no-nis
                          -no-cups
                          -no-glib
                          -no-iconv
                          -nomake examples
                          -nomake tools
                          -skip qtvirtualkeyboard
                          -I/usr/local/tslib/include
                          -L/usr/local/tslib/lib

                          exit
                          2.4: ./build.sh
                          2.5: make
                          2.6: sudo make install

                        3. tar /usr/local/tslib and /opt/qt5.7.0

                        4. for arm platform
                          4.1: cp qt5.7.0.tar.gz and tslib.tar.gz to /opt
                          4.2: tar zxvf qt5.7.0.tar.gz and tar zxvf tslib.tar.gz
                          4.3: vim /etc/profile
                          #add for qt
                          export TSLIB_ROOT=/opt/tslib
                          export QT_ROOT=/opt/qt5.7.0
                          export TSLIB_TSDEVICE=/dev/input/event0
                          export TSLIB_TSEVENTTYPE=input
                          export TSLIB_CONFFILE=/opt/tslib/etc/ts.conf
                          export TSLIB_CALIBFILE=/etc/pointercal
                          export TSLIB_PLUGINDIR=/opt/tslib/lib/ts
                          export TSLIB_CONSOLEDEVICE=none
                          export TSLIB_FBDEVICE=/dev/fb0
                          export QWS_MOUSE_PROTO=tslib:/dev/input/event0
                          export LD_LIBRARY_PATH=/lib:/usr/lib:$QT_ROOT/lib:$TSLIB_ROOT/lib:$TSLIB_ROOT/lib/
                          export QT_QPA_PLATFORM_PLUGIN_PATH=$QT_ROOT/plugins
                          export QT_QPA_PLATFORM=linuxfb:tty=/dev/fb0
                          export QT_QPA_FONTDIR=$QT_ROOT/lib/fonts
                          export QT_QPA_GENERIC_PLUGINS=tslib
                          4.4: source /etc/profile
                          4.5: cd /opt/tslib/bin and then run ./ts_calibrate
                          4.6: write an test example
                          qmake test_qt.pro
                          make
                          adb push test_qt /home/demo
                          4.6: cd /home/demo and then ./test_qt

                        after l run ./test_qt, there is nothing in lcd,so l write test framebuffer code to test fb driver, it's show ok,
                        but if l add "ioctl(fbFd, FBIOPAN_DISPLAY, &vinfo)" in test_qt demo, it's show ok, but it just show one frame, unable to self-refresh,

                        for step 4.5 and 4.6, l use another method to test, but there is still nothing in lcd.
                        4.5: ./ts_calibrate -qws
                        4.6: ./test_qt -qws

                        note: there is no touch screen in my whole steps.

                        1 Reply Last reply
                        0
                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #14

                          What OS are you running on your target ?

                          Interested in AI ? www.idiap.ch
                          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                          J 1 Reply Last reply
                          0
                          • SGaistS SGaist

                            What OS are you running on your target ?

                            J Offline
                            J Offline
                            junzhang
                            wrote on last edited by
                            #15

                            @SGaist
                            / # uname -a
                            uname -a
                            Linux mdm9607 3.18.20 #1 PREEMPT Mon Feb 13 10:40:15 CST 2017 armv7l GNU/Linux
                            / #

                            1 Reply Last reply
                            0
                            • SGaistS Offline
                              SGaistS Offline
                              SGaist
                              Lifetime Qt Champion
                              wrote on last edited by
                              #16

                              The distribution would be more useful.

                              Also, are you running your application as root ?

                              What exact message are you getting on the console when you launch the application ?

                              Interested in AI ? www.idiap.ch
                              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                              J 2 Replies Last reply
                              0
                              • SGaistS SGaist

                                The distribution would be more useful.

                                Also, are you running your application as root ?

                                What exact message are you getting on the console when you launch the application ?

                                J Offline
                                J Offline
                                junzhang
                                wrote on last edited by junzhang
                                #17

                                @SGaist
                                yes, we run an application with root access.
                                we test with Qt/examples/qws/framebuffer, the message is below:

                                root@mdm9607:/home# ./framebuffer
                                ./framebuffer
                                The framebuffer device was opened successfully.

                                Fixed screen info:
                                id: mdssfb_20000
                                smem_start: 0x8fc80000
                                smem_len: 155648
                                type: 0
                                type_aux: 0
                                visual: 2
                                xpanstep: 1
                                ypanstep: 1
                                ywrapstep: 0
                                line_length: 480
                                mmio_start: 0x0
                                mmio_len: 0
                                accel: 0

                                The framebuffer device was mapped to memory successfully.

                                Successfully switched to graphics mode.

                                Variable screen info:
                                xres: 240
                                yres: 320
                                xres_virtual: 240
                                yres_virtual: 320
                                yoffset: 0
                                xoffset: 0
                                bits_per_pixel: 16
                                grayscale: 0
                                red: offset: 11, length: 5, msb_right: 0
                                green: offset: 5, length: 6, msb_right: 0
                                blue: offset: 0, length: 5, msb_right: 0
                                transp: offset: 0, length: 0, msb_right: 0
                                nonstd: 0
                                activate: 16
                                height: -1
                                width: -1
                                accel_flags: 0x0
                                pixclock: 0
                                left_margin: 0
                                right_margin: 0
                                upper_margin: 0
                                lower_margin: 0
                                hsync_len: 0
                                vsync_len: 0
                                sync: 0
                                vmode: 0

                                Frame Buffer Performance test...
                                Average: 395 usecs
                                Bandwidth: 375.791 MByte/Sec
                                Max. FPS: 2531.646 fps

                                Will draw 3 rectangles on the screen,
                                they should be colored red, green and blue (in that order).
                                Done.
                                root@mdm9607:/home#

                                l change the Qt/examples/qws/framebuffer/main.c
                                void drawRect_rgb16(int x0, int y0, int width, int height, int color)
                                {
                                const int bytesPerPixel = 2;
                                const int stride = finfo.line_length / bytesPerPixel;
                                const int red = (color & 0xff0000) >> (16 + 3);
                                const int green = (color & 0xff00) >> (8 + 2);
                                const int blue = (color & 0xff) >> 3;
                                const short color16 = blue | (green << 5) | (red << (5 + 6));

                                short *dest = (short*)(frameBuffer)
                                	  + (y0 + vinfo.yoffset) * stride
                                	  + (x0 + vinfo.xoffset);
                                
                                int x, y;
                                for (y = 0; y < height; ++y) {
                                    for (x = 0; x < width; ++x) {
                                        dest[x] = color16;
                                    }
                                    dest += stride;
                                }//add by junzhang
                                if(ioctl(fbFd, FBIOPAN_DISPLAY, &vinfo)!= 0)
                                {
                                    return -1;
                                }//
                                

                                }
                                there is nothing in lcd unless l add that code when l test with framebuffer example, the message is the same whether l add that code or not.

                                1 Reply Last reply
                                0
                                • SGaistS SGaist

                                  The distribution would be more useful.

                                  Also, are you running your application as root ?

                                  What exact message are you getting on the console when you launch the application ?

                                  J Offline
                                  J Offline
                                  junzhang
                                  wrote on last edited by
                                  #18

                                  @SGaist
                                  l want to add
                                  if(ioctl(fbFd, FBIOPAN_DISPLAY, &vinfo)!= 0)
                                  {
                                  return -1;
                                  }/
                                  to the code which update framebuffer in Qt,
                                  it's mean that if something update in Qt, it will be write data to framebuffer, so, i will add that code in the function which update framebuffer.
                                  it's that ok?
                                  if ok, pls tell which function update framebuffer. thx.

                                  1 Reply Last reply
                                  0
                                  • SGaistS Offline
                                    SGaistS Offline
                                    SGaist
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #19

                                    You likely should check the QLinuxFbScreen class.

                                    Interested in AI ? www.idiap.ch
                                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                    J 1 Reply Last reply
                                    0
                                    • SGaistS SGaist

                                      You likely should check the QLinuxFbScreen class.

                                      J Offline
                                      J Offline
                                      junzhang
                                      wrote on last edited by
                                      #20

                                      @SGaist
                                      thx, l found it and it's show ok.

                                      1 Reply Last reply
                                      0
                                      • SGaistS Offline
                                        SGaistS Offline
                                        SGaist
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #21

                                        Do you mean by adding you ioctl code ?

                                        Interested in AI ? www.idiap.ch
                                        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                        J 1 Reply Last reply
                                        0
                                        • SGaistS SGaist

                                          Do you mean by adding you ioctl code ?

                                          J Offline
                                          J Offline
                                          junzhang
                                          wrote on last edited by
                                          #22

                                          @SGaist
                                          yes, l add inctl to refresh data to lcd.

                                          1 Reply Last reply
                                          0

                                          • Login

                                          • Login or register to search.
                                          • First post
                                            Last post
                                          0
                                          • Categories
                                          • Recent
                                          • Tags
                                          • Popular
                                          • Users
                                          • Groups
                                          • Search
                                          • Get Qt Extensions
                                          • Unsolved