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Some notes for getting Qt OpenGL working on Gumstix Overo (draft)

The goal is to get a working 3.2 kernel Overo system with Qt embedded and OpenGL support so we can run our custom Qt OpenGL apps on the Gumstix.

These instructions could probably be modified to support Qt-X11, but I don't use X with the Gumstix and have not tried that.

The kernel and rootfs were built using Yocto. Qt and the TI graphics SDK are built outside of Yocto/OE, but using the same cross-build tools.

The assumption for all of this is that you have already successfully built a Gumstix image with a 3.2 kernel using Yocto.

If your image contains Qt embedded then you should create a new image recipe that omits that. Qt will be built and installed separately.

The PowerVR drivers are closed-source. You can get them as part of the TI Linux Graphics SDK. There are different drivers based on the version of the SGX core. I'll be targeting the DM3730 core in this document, but I will point out the small configuration difference for the OMAP3530 core. I did verify the OMAP35xx builds work with recent cores. You'll have to use a different version of the TI Graphics SDK if your Gumstix/SGX core is too old.

I am using the soft-fp builds of the SGX driver currently. The drivers are available in a hard-fp version, but I haven't tried them yet.


1) Patch the kernel DSS driver and rebuild the 3.2 kernel

2) Build the kernel modules

3) Build Qt with the powervr plugin

4) Copy components to the Gumstix SD card

5) Finish install on the Gumstix

6) Run some demos

For the example, I am using a Yocto build where my TMPDIR is at /oe5.

The meta-layer I am using is called meta-pansenti. There is no requirement to use this layer, but paths referenced will have this name in them.

You can get it here :

I'm using the pansenti-sgx-image recipe for the rootfs.

The kernel comes from Steve Sakoman's repository.



1) Patch the DSS driver in the kernel

The kernel recipe is here


Copy this patch file in sgx-qt-build/kernel-3.2/0001-Revert...-v3.2.patch to your kernel recipe directory. (The patch comes from Robert Nelson. See the References section at the end of this document.)

For instance, in my repo the kernel recipe directory would be this


Then modify the kernel recipe, to add the DSS patch. Here is what mine looks like. The libertas patch is unrelated.


    DESCRIPTION = "Linux kernel for OMAP processors"


    BOOT_SPLASH = ""

    PV = "3.2"

    S = "${WORKDIR}/git"

    SRC_URI = "git://;branch=omap-3.2;protocol=git \
           file://defconfig \
               file://libertas-async-fwload.patch \
               file://0001-Revert-OMAP-DSS2-remove-update_mode-from-omapdss-v3.2.patch \

2) Rebuild the kernel with

    bitbake -c cleansstate virtual/kernel
    bitbake virtual/kernel

3) Rebuild your image. It should not include Qt, but should include the following if you plan on using a touchscreen.


4) You should probably install your new image on an SD card and make sure everything is still working before proceeding.


TI documentation for their Graphics SDK can be found here

From the above wiki link in the table in the 'About Graphics SDK', it shows that there are differences in the SGX Core revisions used by the OMAP35xx and DM37xx SOCs.

As a result, the binaries from the SDK are specific to the SGX core you are targetting.

1) Download the TI Graphics SDK from here

I am using version of the SDK for this example.

2a) If you are on a 64-bit platform, I believe you need the 32-bit compatibility libraries to execute the bin file. You should do this first.

Ubuntu users can use this command

    sudo apt-get install ia32-libs

If you are on a 32-bit platform, this isn't necessary.

2b) Extract the SDK by running the binary: Graphics_SDK_setuplinux_4_08_00_01.bin

The default extract location is


which I'll use.

When prompted, you should select es3.x, es5.x and the SDK.

3) Add some Yocto built cross-tools to your PATH.

I have a script that I use for this kind of thing I call It can be found in the root of the sgx-qt-build/ directory.

Run it like this substituting the OETMP for your Yocto build.

    scott@quad:~$ export OETMP=/oe5
    scott@quad:~$ source ~/sgx-qt-build/

The default in is for Overo Storm boards (DM37xx). Change the SGX_BIN_DIR variable in to ...es3.x.. to target OMAP35xx boards.

4) Copy the example Rules.make to the SDK directory.

The example is sgx-qt-build/4.-8.00.01/Rules.make.

    scott@quad:~$ cp ~/sgx-qt-build/ ~/Graphics_SDK_4_08_00_01/

You should not have to modify it.

5) Apply a small kernel definition patch to the SDK source. (A renaming of a definition from ..FREEZEABLE.. to ..FREEZABLE..)

Copy the patch to the Graphics SDK directory

    scott@quad:~$ cd Graphics_SDK_4_08_00_01
    scott@quad:~/Graphics_SDK_4_08_00_01$ cp ~/sgx-qt-build/ .

Apply the patch

    scott@quad:~/Graphics_SDK_4_08_00_01$ patch -p1 < omaplfb_freezable.patch

6) Running 'make help' will show you the build options available.

    scott@quad:~/Graphics_SDK_4_08_00_01$ make help

    Usage (for build): make BUILD={debug | release} OMAPES={3.x | 5.x | 6.x | 8.x} FBDEV={yes | no} SUPPORT_XORG= {1 | 0 }  all
          Platform                                  OMAPES 
          --------                                  ------ 
          OMAP35x(SGX core 1.2.1)                    3.x   
          OMAP37x/AM37x(SGX core 1.2.5)              5.x   
          816x(389x)/814x(387x)(SGX core 1.2.5)      6.x   
          335x(SGX core 1.2.5 )                      8.x   
    --> Specifying OMAPES is mandatory. BUILD=release and FBDEV=yes SUPPORT_XORG=0(not enabled) by default
    Usage (for install): make BUILD=(debug | release} OMAPES={3.x | 5.x | 6.x | 8.x} EGLIMAGE={1 | 0} install
    --> See online Graphics Getting Started Guide for further details.

7) To build the kernel drivers for the DM3730, run the following

    scott@quad:~/Graphics_SDK_4_08_00_01$ make BUILD=release OMAPES=5.x FBDEV=yes

Ignore the warnings you get about devmem2.

When it completes, you should see some kernel modules in the gfx_rel_es5.x subdirectory.

    scott@quad:~/Graphics_SDK_4_08_00_01$ ls -l gfx_rel_es5.x/*.ko
    -rw-rw-r-- 1 scott scott  130076 Oct 24 13:54 gfx_rel_es5.x/bufferclass_ti.ko
    -rw-rw-r-- 1 scott scott  320884 Oct 24 13:54 gfx_rel_es5.x/omaplfb.ko
    -rw-rw-r-- 1 scott scott 2129793 Oct 24 13:54 gfx_rel_es5.x/pvrsrvkm.ko

If you were building for the OMAP3530, you would have run this make command

    scott@quad:~/Graphics_SDK_4_08_00_01$ make BUILD=release OMAPES=3.x FBDEV=yes

The OMAP3530 kernel modules will be in the gfx_rel_es3.x subdirectory.

That's all for the PowerVR drivers.


These instructions are for Qt version 4.8.3. This was the latest Qt4 version when I wrote this.

The cross-built Qt will be installed into /opt on both the build workstation and the Gumstix root filesystem. You will need permissions in /opt.

1) Download the Qt source code from here

2) Extract the Qt source code to a convenient directory for building. I'm going to use my home directory.

    scott@quad:~$ tar xzf /oe-sources/qt-everywhere-opensource-src-4.8.3.tar.gz

3) (Optional) Make a shorter soft link for convenience

    scott@quad:~$ ln -s qt-everywhere-opensource-src-4.8.3/ qt

    scott@quad:~$ ls -ld qt*
    lrwxrwxrwx  1 scott scott   35 Oct 24 14:30 qt -> qt-everywhere-opensource-src-4.8.3/
    drwxr-xr-x 16 scott scott 4096 Sep 12  2011 qt-everywhere-opensource-src-4.8.3

4) Apply this pvrqwswsegl.patch to the Qt source.

Copy the patch to the Qt source directory.

    scott@quad:~$ cp sgx-qt-build/qt-4.8.3/pvrqwswsegl.patch qt

Apply the patch

    scott@quad:~$ cd qt
    scott@quad:~/qt$ patch -p1 < pvrqwswsegl.patch

5) Create a make specification (mkspec) for the overo cross build.

There is an example mkspec in the sgx-qt-build directory.

    scott@quad:~/qt$ cd mkspecs/qws
    scott@quad:~/qt/mkspecs/qws$ cp -r ~/sgx-qt-build/ .

6) Create a new include directory in the TI Graphics SDK directory that Qt will look for.

    scott@quad:~/qt/mkspecs/qws/linux-overo-g++$ cd ~/Graphics_SDK_4_08_00_01/include
    scott@quad:~/Graphics_SDK_4_08_00_01/include$ mkdir GLES
    scott@quad:~/Graphics_SDK_4_08_00_01/include$ cp OGLES2/EGL/eglplatform.h GLES/

6) Configure Qt, targeting /opt for the eventual install.

First change permissions for /opt.

    scott@quad:~/qt$ sudo chown -R scott:scott /opt

Copy the script to the qt directory.

    scott@quad:~/qt$ cp ~/sgx-qt-build/qt-4.8.3/ .

Make sure you have the environment setup if you are running this in a new shell then run this again substituing your OETMP.

    scott@quad:~$ export OETMP=/oe5
    scott@quad:~$ source ~/sgx-qt-build/

Run the script, answering the licensing questions as appropriate. I choose LGPL.

    scott@quad:~/qt$ ./

7) Build Qt

    scott@quad:~/qt$ make 

Optionally, and for a big speed improvement, add -j N parameter to make. N should be the number of cpu cores you want to use.

For example

    scott@quad:~/qt$ make -j6

8) Install Qt on the local workstation to the /opt directory. This just collects the libs, headers and demos/examples that need to go to the target into one location. They'll be copied to the Gumstix SD card in another step.

Run the install step like this

    scott@quad:~/qt$ make install

You should have a new directory /opt/qte


Setup your SD card as you usually would with a boot partition and rootfs.

On the system I writing this on, the SD card shows up as /dev/sdb. Remount the rootfs partition and copy over the TI Graphics components and the Qt software that was built above.

Mount the Gumstix rootfs partition

    scott@quad:~$ sudo mount /dev/sdb2 /media/card

Create an /opt directory on the Gumstix rootfs

    scott@quad:~$ sudo mkdir /media/card/opt

Copy the TI Graphics stuff

    scott@quad:~$ sudo cp -r ~/Graphics_SDK_4_08_00_01/gfx_rel_es5.x /media/card/opt

For OMAP35xx builds, copy gfx_rel_es3.x

    scott@quad:~$ sudo cp -r ~/Graphics_SDK_4_08_00_01/gfx_rel_es3.x /media/card/opt

Copy Qt

    scott@quad:~$ sudo cp -r /opt/qte/ /media/card/opt

Unmount the SD card

    scott@quad:~$ sync
    scott@quad:~$ sudo umount /dev/sdb2

Put the SD card in the Gumstix and boot it.

5. Finish install on the Gumstix

1) Install the GFX components. This copies various GFX scripts, libraries, kernel modules and demo programs to standard locations.

From here out, substitute gfx_rel_es3.x for gfx_rel_es5.x if you built for an OMAP35xx system.

    root@overo:~# cd /opt/gfx_rel_es5.x/
    root@overo:/opt/gfx_rel_es5.x# ./

You can ignore the message to reboot.

Run depmod to let the system know about the new drivers

    root@overo:/opt/gfx_rel_es5.x# depmod

2) The PowerVR software needs an initialization file that tells it about Qt. Create an /etc/powervr.ini file that looks like this


Note: If you are interested in running non-Qt demos that came with the TI SDK then you will want another library in place of TODO: Add the reference doc for this.

3) Add the Qt libraries to the library path.

Add this line to /etc/


Then force a refresh of the run-time linker database

    root@overo:~# rm /etc/
    root@overo:~# ldconfig -v

4) Load the kernel drivers.

There is a script to do this in /etc/init.d called rc.pvr.

    root@overo:~# /etc/init.d/rc.pvr start

    root@overo:~# lsmod
    Module                  Size  Used by
    omaplfb                11582  0 
    pvrsrvkm              160943  1 omaplfb
    libertas_sdio          16208  0 
    libertas               99103  1 libertas_sdio
    cfg80211              165642  1 libertas
    rfkill                 17069  1 cfg80211
    lib80211                5017  1 libertas
    firmware_class          6797  2 libertas_sdio,libertas
    ads7846                10347  0 

Your modules may differ based on your kernel config. The important ones for this are omaplfb and pvrsrvkm.

You can add rc.pvr to your startup scripts.


I've used both DVI displays and Gumstix 4.3" touchscreens with this Qt/OpenGL system and both work.

The dvi kernel boot params that I've tried are


with the following resolutions


and omapfb.mode=dvi:640x480MR-32@60

You can adjust these settings in your u-boot environment.

There are some Qt demos under /opt/qte/examples/opengl

A fun one to try is hellogl_es2.

    root@overo:~# cd /opt/qte/examples/opengl/hellogl_es2
    root@overo:/opt/qte/examples/opengl/hellogl_es2# ./hellogl_es2 -qws -display powervr

For the 32-bit color 640x480 mode you have to specify a proper rgba setting first or you get error like (3) in the troubleshooting section.


1) You get the following error when running the hellogl_es2 demo

    root@overo:/opt/qte/examples/opengl/hellogl_es2# ./hellogl_es2 -qws -display powervr
    QEglContext::createSurface(): Unable to create EGL surface, error = 0x300b

You likely forgot or improperly configured /etc/powervr.ini

2) You get the following loading the kernel modules (/etc/init.d/rc.pvr start)

    PVR_K: (FAIL) SGXInit: Incompatible HW core rev (10003) and SW core rev (10201).

Your SGX core is too old. It is reporting version 1.0.3 and version 1.2.1 is the minimum supported by this SDK.

3) You get the following error running demos on the touchscreen

    root@overo:/opt/qte/examples/opengl/hellogl_es2# ./hellogl_es2 -qws -display powervr
    /dev/fb0: could not find a suitable PVR2D pixel format
    Could not initialize EGL display - are the drivers loaded?
    /dev/fb0: could not find a suitable PVR2D pixel format
    powervr: driver cannot connect

The framebuffer needs to be reconfigured. You can use fbset to fix this.

The default fbset that gets installed is part of BusyBox and doesn't support framebuffer mode changes like this.

If you included the standalone fbset package in your Yocto image recipe, version 2.1.x, then the following will work.

First unload the sgx kernel drivers

    root@overo:# /etc/init.d/rc.pvr stop

Then change the framebuffer.

Check the current settings

    root@overo:~# fbset

    mode "640x480-61"
        # D: 24.000 MHz, H: 30.000 kHz, V: 60.730 Hz
        geometry 640 480 640 480 32
        timings 41666 80 48 3 7 32 4
        rgba 8/16,8/8,8/0,0/0

Change them

    root@overo:~# fbset -rgba 8/16,8/8,8/0,8/24

Check that they took.

    root@overo:~# fbset

    mode "640x480-61"
        # D: 24.000 MHz, H: 30.000 kHz, V: 60.730 Hz
        geometry 640 480 640 480 32
        timings 41666 80 48 3 7 32 4
        rgba 8/16,8/8,8/0,8/24

Reload the sgx drivers

    root@overo:~# /etc/init.d/rc.pvr start

After that you can run the hellogl_es2 example and it should run at >100 fps on a DM37xx at least.


Robert Nelson's DSS patch for 3.2

TI documentation for their Graphics SDK can be found here

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