Getting Qt 4.3.2 running on the Chumby

The libraries

First, we need the GNU toolchain to cross-compile things for the Chumby. Download and install it from:

Now, we need to decide where to install our files to; i.e., our prefix. Since I'm having some trouble with my NFS share, I'll use my USB stick. (Located at /mnt/usb). Feel free to replace this with your prefix wherever you see me mention this location. Next, we need to download and install tslib for the touchscreen.

I used version 1.0 from:

Make sure you have autoconf, libtool, and the other usual suspects installed. Then from the extracted files directory run:


./configure --prefix=/mnt/usb --host=arm-linux
What next? You guessed it:

If you get some errors about rpl_malloc, simply comment out that evil line in config.h and try make again.

And finally:

make install

Next up is Qt.


Unpack it, and run:

./configure -embedded arm -pch -prefix /mnt/usb -qt-kbd-usb -qt-mouse-tslib \
-L/mnt/usb/lib/ -I/mnt/usb/include/ -nomake examples -nomake demos

Note:You can leave out the -qt-kbd-usb if you want. I kept it in since I like being able to type on the Chumby with my USB keyboard ;). Also, thanks to orangerobot from the Chumby forum for pointing out the mangled -L line.


make install


So far we don't have any Qt programs to play with. Let's compile a small Qt widget/app called PictureFlow ( by Ariya Hidayat.

I have modified the sources slightly (added basic mouse support, some images, resizing), and packaged it here:

 Uncompress it, and in that very directory:


Copy the resulting binary and images to a place on your prefix:

mkdir /mnt/usb/test
cp pictureflow *jpg /mnt/usb/test/

Now, we need to create a file with some environment variables that you can use when you're in your Chumby shell.

Create a file in your prefix (/mnt/usb for me) called chumby.env with the following contents:

export TSLIB_TSDEVICE=/dev/input/event0
export TSLIB_FBDEVICE=/dev/fb0
export TSLIB_PLUGINDIR=/mnt/usb/lib/ts
export TSLIB_CONFFILE=/mnt/usb/etc/ts.conf
export TSLIB_CALIBFILE=/mnt/usb/etc/pointercal
export LD_LIBRARY_PATH=/lib:/mnt/usb/lib
export POINTERCAL_FILE=/mnt/usb/etc/pointercal
export QWS_MOUSE_PROTO=Tslib:/dev/input/event0
export QWS_KEYBOARD=USB:/dev/input/event1

Finally it's Chumby time!

Enable SSH on the Chumby as per:

SSH in and cd in to your directory of installed files.

For me, this meant:

Plugging in my USB stick.
ssh root@<ChumbyIpAddress>

cd /mnt
umount usb
mount usb
cd usb

Lets start off by killing the current Chumby GUI:


Now, we need to source that file with environment variables:

source /mnt/usb/chumby.env

Then, we need to configure the touch screen for tslib.

Make sure that your etc/ts.conf file has the input module un-commented.

My /mnt/usb/etc/ts.conf looks like:

module_raw input
module pthres pmin=1
module variance delta=30
module dejitter delta=100
module linear

Finally, we need to calibrate the touchscreen:


Make sure that you touch the five different crosshair locations. If you accidently tap twice at the same spot, re-run ts_calibrate untill you get it right :)

To test and make sure that tslib is working correctly, feel free to play with:


You should be able to drag the crosshair around.

And last but not least - it's time to try out our Qt app:

cd /mnt/usb/test
./pictureflow -qws

If all is well, you should see something that looks like this:



Note: I only added rudimentary mouse support to it, so it really only cares if you tap on the left or right half of the screen to start swapping covers.

Hopefully you didn't encounter any problems. These steps worked for me, but I may have just been lucky ;). More likely though is that I forgot to mention something. Please feel free to ask questions on this Chumby forum thread:

Allthough I realize that this was quite cumbersome, the good new is that you basically only need to do this once. Thereafter you just need to write your Qt app (Google for tutorials ;)), qmake, make, and copy the executable to your Chumby! :)


It's good to know that PictureFlow can work out-of-box on this cool device :-)

Indeed - and performance is really great! Thanks for making such a neat widget :)

I'd already follow your instruction for build qtopia and all the compiling process works fine, but, when i run ts_calibrate the LCD don't show the crosshair. I set the environment variables as file:///home/cain/Desktop/chumby/qt_on_chumby.html say, but i can't see nothing sad

If i run:

unzip -p /bitmap/ >/dev/fb1

some colored circles are shoen in LCD, why QT applications don't drive the LCD?
There are a environment variable that manage the QT framebuffer device?

When i run:


The framebuffer device was opened successfully.

Fixed screen info:
id: IMX
smem_start: 0xc3d40000
smem_len: 153600
type: 0
type_aux: 0
visual: 2
xpanstep: 0
ypanstep: 0
ywrapstep: 0
line_length: 640
mmio_start: 0x0
mmio_len: 0
accel: 0

The framebuffer device was mapped to memory successfully.

Switch to graphics mode failed: Invalid argumentVariable screen info:
xres: 320
yres: 240
xres_virtual: 320
yres_virtual: 240
yoffset: 0
xoffset: 0
bits_per_pixel: 16
grayscale: 0
red: offset: 8, length: 4, msb_right: 0
green: offset: 4, length: 4, msb_right: 0
blue: offset: 0, length: 4, msb_right: 0
transp: offset: 0, length: 0, msb_right: 0
nonstd: 0
activate: 0
height: -1
width: -1
accel_flags: 0x0
pixclock: 62500
left_margin: 15
right_margin: 6
upper_margin: 9
lower_margin: 7
hsync_len: 1
vsync_len: 1
sync: 0
vmode: 0

Will draw 3 rectangles on the screen,
they should be colored red, green and blue (in that order).

But nothing appear an LCD :(

In your example, you mentioned:
"unzip -p /bitmap/ >/dev/fb1"

On my device, fb0 was what worked. Try running "export TSLIB_FBDEVICE=/dev/fb1"

And let me know if you see when you run ts_calibrate.

Also, make sure your ts.conf file is properly set up as described in the guide.

We can tackle Qt itself after that ;)

Hi Jesper, thanks or your fast answer:
My /mnt/usb/etc/ts.conf is:
module_raw input
module pthres pmin=1
module variance delta=30
module dejitter delta=100
module linear

when i set:

export TSLIB_FBDEVICE=/dev/fb1

and run ts_calibrate the lcd turn in black :(, but the touch screen seem work fine, i see messages when i press the scren

I'm really not sure what this could be. I'll try to follow my steps from scratch this week, and let you know if it works for me. Perhaps something has changed since the Chumby updates have come out...?

Good luck, and keep on trying meanwhile ;)


I update my chumby this week, maybe there are changes.
I have a question:
When you compile qtopia, what color depth are you choice?

Best regards

I am having the same issues with ts_calibrate -- the chumby screen never displays the calibration targets but it does responds to taps.

Setting TSLIB_FBDEVICE=/dev/fb1 causes the same issue described above -- the chumby screen goes black when i run ts_calibrate (and still responds to taps).

Any help would be much appreciated . . .

I recently just tried running through the guide, step by step, on another (clean) machine, and succeeded without any trouble. I really don't know what you can do, but perhaps re-check the guide to make sure you haven't missed anything... Are you doing anything different? (such as not installing to a USB stick for instance - different prefix?) Sorry, and good luck!

Its very good thanks..