Qt5 on TI platforms - with Xcb (part 2)
Submitted by prabindh on Fri, 01/15/2016 - 20:27 / /
This is a temporary location for this post, and would ideally move to a Qt blog, or tigraphics post - please do not link directly here
Introduction:
This short post covers the background of Qt5, architectural details, configuring for xcb build with TI SGX Graphics drivers, building, and known issues. This post does not cover building QtWebkit. If looking for an eglfs build and related information refer to the previous post at below link. http://gpupowered.org/node/8.
(Updated 2013) Post on Qt5 Final 5.0 build instructions: (http://tigraphics.blogspot.in/2013/01/qt-500-final-dec-2012-available-on-ti.html), and for Qt5 Webkit2 refer to (http://www.gpupowered.org/node/15)
Qt5 Architecture:
(updated link after the Digia takeover) http://blog.qt.digia.com/wp-content/uploads/2011/05/Qt5.pdf
Qt5 differences with Qt4:
Qt4 (Qt-embedded) exposed the capabilities of HW in 2 ways - HW that can accelerate rendering of widget surfaces (QPainter operations), and HW that can accelerate screen updates (of QScreen). So if for example an OpenGLES engine was used to accelerate screen display operations (using for example -display powervr), the same engine could not be used for accelerating rendering operations. So essentially, 3D and 2D acceleration mechanisms could not co-exist.
Qt5 tries to eliminate this gap. With the platform plugin approach - the HW "platform" is expected to provide OpenGL ES2, and any other additional HW acceleration on top of that as part of the platform. In essence - with GLES2 - every screen update in Qt5 happens via an OpenGL ES texturing operation, rather than any other means. In addition to this fundamental change, Qt5 brings in another major programming model update - that of QML, Qt3D etc.
A key thing specific to TI (SGX based) platforms - With the elimination of the display plugin, Qt5 no longer uses or supports blits via pvr2d or wsegl, and instead directly uses the egl (or window) capabilities exposed by the GL driver. This eliminates immediately a large portion of pvr2d/wsegl version related issues that cropped up in earlier Qt versions.
(ex patch for Qt4 in below link is not needed anymore)
https://github.com/prabindh/qt-configs/blob/master/qt4.8/001_wsegl2.patch
The below platform plugins are available in the Qt5 Alpha package. Only "eglfs" and "minimal" are built by default in qtbase.
cocoa eglfs linuxfb minimal openvglite platforms.pro qvfb windows
directfb kms openkode openwfd qnx xcb
Qt5 Alpha source package overview:
Qt5 contains the absolute minimum required functionality - in "qtbase" folder. All other additional components (including Qt3D) are split into separate folders. Below is the folder structure of Qt5 (Alpha package)
<>$ ls
build qtdeclarative qt.pro qtwayland
build.dependencies qtdoc qtquick1 qtwebkit
configure qtgraphicaleffects qtscript qtwebkit-examples-and-demos
configure.bat qtimageformats qtsensors qtwebkit.pri
gnuwin32 qtjsbackend qtsvg qtxmlpatterns
qt3d qtlocation qtsystems README
qtbase qtmultimedia qttools
Pre-requisites for Qt5 build (non-webkit):
- Qt5 alpha source package
http://releases.qt-project.org/qt5.0/alpha/
- TI Graphics SDK (4.05 or later), with Xorg support
http://software-dl.ti.com/dsps/dsps_public_sw/sdo_sb/targetcontent/gfxsdk/latest/index_FDS.html
http://processors.wiki.ti.com/index.php/AM35x-OMAP35x_Graphics_SDK_Getting_Started_Guide
- Recent filesystem (based on GCC 4.5 or later) with X11. Dependencies are listed below
libxcb1 libxcb1-dev libx11-xcb1 libx11-xcb-dev libxcb-keysyms1 libxcb-keysyms1-dev libxcb-image0 libxcb-image0-dev libxcb-shm0 libxcb-shm0-dev libxcb-icccm4 libxcb-icccm4-dev libxcb-sync0 libxcb-sync0-dev libxcb-xfixes0-dev libxrender-dev libxcb-shape0-dev libx11-dev
- ARM cross Toolchain (GCC 4.5 or later), example from below:
http://people.linaro.org/~michaelh/incoming/binaries/
Configuring Qt5:
Configuring Qt5 is fairly easy - and can be done without messing with creating new mkspecs, if the below are met:
- a linaro toolchain (linux-arm-gnueabi-)
- sgxconfiguro is used (package config for TI Graphics SDK - egl and x11)
https://github.com/prabindh/sgxconfiguro
- force-pkg-config is used
If this does not seem clear, the older tried-and-tested-method of specifying all possible (and needed) paths in the qmake.conf as below will also work :
https://github.com/prabindh/qt-configs/tree/master/qt5.0_mar2012
Modified Qt5 configure script that includes sgxconfiguro support is provided in github.
https://github.com/prabindh/qt-configs/tree/master/qt5_alpha
The below method adopts the first approach and uses the standard Qt5 supplied linux-arm-gnueabi-g++ mkspec without change
$cd qtbase
$export PATH=/opt/linaro/gcc-linaro-arm-linux-gnueabi-2012.03-20120326_linux/bin:/home/prabindh/work1/arm-qt5-tar/qt-everywhere-opensource-src-5.0.0/qtbase/bin:
$export PKG_CONFIG=./x86-cross-ubuntu-pkg-config
$./configure -prefix /home1/prabu/qt5_xcb_install -release -make libs -xplatform linux-TIarmv7-sgx-g++ -opengl es2 -confirm-license -opensource -xcb -no-wayland -force-pkg-config -make examples -make demos -verbose
From the logs, configure should have detected the below functionality - key are NEON, OpenGL, and Xcb support
Build .................. libs examples demos
Configuration .......... cross_compile release shared dll qpa largefile stl precompile_header neon pcre minimal-config small-config medium-config large-config full-config fontconfig libudev evdev xlib xrender xcb-xlib accessibility egl eglfs opengl opengles2 qpa reduce_exports reduce_relocations clock-gettime clock-monotonic mremap getaddrinfo ipv6ifname getifaddrs inotify png system-freetype system-zlib nis iconv glib xcb alsa icu concurrent audio-backend v8 v8snapshot release
Debug .................. no
QtDBus module .......... no
QtConcurrent code ...... yes
QtGui module ........... yes
QtWidgets module ....... yes
JavaScriptCore JIT ..... To be decided by JavaScriptCore
Declarative debugging ...yes
STL support ............ yes
PCH support ............ yes
iWMMXt support ......... no
NEON support ........... yes
IPv6 ifname support .... yes
getaddrinfo support .... yes
getifaddrs support ..... yes
Accessibility .......... yes
NIS support ............ yes
CUPS support ........... no
Iconv support .......... yes
Glib support ........... yes
GStreamer support ...... no
PulseAudio support ..... no
Large File support ..... yes
GIF support ............ plugin
JPEG support ........... plugin (qt)
PNG support ............ yes (qt)
zlib support ........... system
Session management ..... auto
libudev support ........ yes
OpenGL support ......... yes (OpenGL ES 2.x)
OpenVG support ......... no
XShape support ......... auto
XVideo support ......... auto
XSync support .......... auto
Xinerama support ....... runtime
Xcursor support ........ runtime
Xfixes support ......... runtime
Xrandr support ......... runtime
Xi support ............. runtime
MIT-SHM support ........ auto
FontConfig support ..... auto
XKB Support ............ auto
immodule support ....... yes
GTK theme support ...... auto
SQLite support ......... plugin (qt)
OpenSSL support ........ no
Alsa support ........... yes
libICU support ......... yes
PCRE support ........... qt
Xcb support ............ limited (old version)
Xrender support ........ yes
EGLFS support .......... yes
After configure, make && make install are to be done. This is important, as qmake needs to be in the install path for the next steps of building other modules outside of qtbase.
Steps to build Qt3D :
To build Qt3D, in addition to qtbase also need to build the below:
qtjsbackend (has v8)
qtdeclarative
qt3d
To build the above, enter the directory, then perform (assuming qmake is in the path as specified earlier)
$ qmake && make && make install
Checking the build output:
As a result of the build, the QtCore libraries, QtGui etc are all built. Also, the "eglfs" and "minimal" platform plugins are built by default. Note that "eglfs" draws onscreen using egl, while "minimal" draws to an offscreen pixmap image. The Xcb platform relies on presence of a X server in the system.
Example precompiled binary of Qt5:
A set of binaries built from above approach is provided below. To use this in the target filesystem, extract the below archive into /home1/prabu/ (Qt expects the same path while executing). Any filesystem with a recent enough libc (from >= gcc4.5) should be sufficient.
https://gforge.ti.com/gf/download/docmanfileversion/298/5546/qt5_xcb_install.tar.gz
Screen captures of live demos on 3730:
Pictures and videos are posted at,
Stickman and colliding mice demos:
https://www.youtube.com/watch?v=4jsd0FnFcrk
https://www.youtube.com/watch?v=kyEXhfzY4OA
Executing demos on target:
Compared to eglfs approach, since the rendering is handled by Xserver, there is no need to set QPA basics (for ex. resolution).
1) Ensure SGX drivers are installed, and standard GLES2 3D demos are functional without Qt (refer to below link for more details on Xorg build)
http://processors.wiki.ti.com/index.php/Graphics_SDK_Quick_installation_and_user_guide#Xorg_build
2) With the Graphics SDK correctly installed, the /etc/powervr.ini file will have the correct WindowSystem already set.
WindowSystem=libpvrPVR2D_DRIWSEGL.so
3) Running QML demos:
QMLScene can be used to run QML demos, with a command similar to below:
/bin/qmlscene examples/qtdeclarative/qtquick/animation/pathanimation/pathanimation.qml
Note that if the SGX accelerated Xserver is not running on the system, the below message will be printed, and the demo will not run
No platform plugin argument was specified, defaulting to "xcb".
QXcbConnection: Could not connect to display
Aborted
4) Running standalone demos:
Standalone qt5 demos (including qt3d demos, as well as classic qtbase demos like animatedtiles) can be invoked as below for Xcb platform (default), after entering into the demo folder
./
ex, ./collidingmice
No arguments are necessary as Xcb platform is the default.
Tslib support:
Provided by default
Cursor support:
Provided by default
Screen Rotation support:
TODO
CPU Loading:
TODO
Notes:
- Qt5 documentation for the APIs still need to be updated. All Qt5 docs ex, below are misleading (they point to Qtembedded docs)
http://doc.qt.nokia.com/qt5/qt-embedded-pointer.html
========
prabindh@yahoo.com, April 2012