Action Item #694


Verify touchscreen works with launcher

Added by Hammel over 5 years ago. Updated over 5 years ago.

Target version:
Start date:
02 Mar 2019
Due date:
% Done:


Estimated time:
01 - Critical


The touch library appears to be okay, so now try the launcher and see what happens.

Actions #1

Updated by Hammel over 5 years ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 10

The launcher doesn't work with the touch screen because
a) firstboot doesn't properly test if the screen is a touchscreen
b) piboxLoadDisplayConfig() doesn't properly check if the configuration file (pibox-config) shows it's a touch screen.

There are two things that need to be fixed.
1. Fix firstboot. There is a section that tests if the display size is 800x400, which just happens to match the official Raspberry Pi touchscreen display size. This now needs to use ptests -t17 which will either report the name of the touch screen (only two are currently supported) or Not found if no touchscreen is found. This is a little slow but it only has to happen on firstboot.
2. Fix piboxLoadDisplayConfig() to use the third line of the pibox-config file to determine if we're on a touch screen.

There is also a new piboxTouchGetDeviceName() API call but that can't be used until the touch screen service is started and the launcher (and other apps) don't start it unless piboxLoadDisplayConfig() tells them they have a touch screen. So there is no function (yet, maybe in the future - some variation of the ts_setup in touchProcessor.c) in the APIs that can query tslib directly to find out if we're using a touchscreen.

Note that I can't call piboxTouchGetDeviceName() from piboxLoadDisplayConfig() because the latter doesn't know if the touchscreen service has been initialized yet. So it reads the static configuration to find out.

Actions #2

Updated by Hammel over 5 years ago

ptest -t17 doesn't always work unless I set a long timeout. This is because it sets up a thread before it does it's work and the work becomes async to the test. So this is far from ideal for testing if I have a touchscreen device.

A better solution is to simply use the scan_devices code from tslib. This is exactly what I want. But it's not an exposed API in tslib. Instead I need to call ts_setup and then check the return value to see if it's non-null. If it is, then we have a touchscreen device. Of course, this doesn't necessarily map to one of the devices we support. So we'd need to have a new function in libpibox:touchscreen.c that runs the EVIOCGNAME ioctl on a path (returned in the struct tsdev from tslib:ts_setup) to check if the name matches one we support.

Since this isn't a test of the library I'll need to add another dir for a special program generated from libpibox that can do all this and skip use of ptests by firstboot.

Actions #3

Updated by Hammel over 5 years ago

  • % Done changed from 10 to 20

Implemented pbtouchstate tool.

Now I can update firstboot to use it.

Actions #4

Updated by Hammel over 5 years ago

All of the changes to libpibox and launcher have been made (though not all are checked in). I've built a libpibox pkg and installed it on the Xeon. I'm building the meta packages now and will install them as well. Then I'll build a launcher package (with latest updates) and install those. At that point I can test the launcher.

I need to verify the current installation on the Xeon boots without the packages, just to be safe. I'll need network access up and running automatically to verify my tests.

Actions #5

Updated by Hammel over 5 years ago

This still isn't working after many updates to clean up the code and rebase with upstream kernel, etc.

I need to find a way to debug why X works but tslib via my library is not. I can try various things like ts_read_raw() or ts_read_mt() and nonblocking reads (again). But I don't really know which way to go at this point.

Still digging around.

Actions #6

Updated by Hammel over 5 years ago

I disabled the launcher so X comes up in dev mode. Then I ran evtest. Interestingly: there is no /dev/input/event0. They start with event1. Anyway, evtest doesn't work. Also, the mouse on the favi(like) keyboard doesn't work either. So something else is up here. It's not my library. It's some kind of config problem.

Actions #7

Updated by Hammel over 5 years ago

I found the problem: The display gets two event devices, one for the touch screen one for a mouse (not sure where the second one comes from - seems like I did something to make that show up because it wasn't there before - I don't think). The hid_multitouch driver hides the first one so only the mouse device is still there after that driver loads. That device doesn't work with the touchscreen. So don't load that driver and you see both devices. And now I need to go back to exact matches for device names because the two devices from this display have the same prefix but with "(Mouse)" appended to the second one, so a substring match won't work to get the device I actually need.

I fixed these things and tested with evtest. That worked fine just under an xterm. So I re-enabled the launcher and tried again. This time I could tell it got the right device and when I pressed the terminal icon I got the xterm!! Woohoo! The device now works.

So now I need to make the changes in the source trees and rebuild the image. Once that's verified and changes pushed I can close this issue and move on to making the real phone.

Actions #8

Updated by Hammel over 5 years ago

  • Status changed from In Progress to Closed
  • % Done changed from 20 to 100

I had to get all my eggs in a row with this. There were changes to the dev build and libpibox and launcher and I had to make sure the dev build picked up the changes to libpibox, while the launcher was compiled with those changes. Plus I had to get changes integrated into the firstboot to properly identify the touchscreens.

Touchscreen is now working properly for Xeon. I've also verified that the changes are backwards compatible with the official RPi touchscreen. Also verified changes do not regress use on non-touchscreens.

All changes committed and pushed.

Closing issue.


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