Eglfs on second display

JohanD

Hi all,

I am working on an embedded system with two displays connected. (Nitrogen6q board with i.mx6 cpu)
With "-platform linuxfb" I can choose the display to run the application on like this:

First display: ./analogclock -platform linuxfb:"fb=/dev/fb0"
Second display: ./analogclock -platform linuxfb:"fb=/dev/fb2"

with "-platform eglfs" the application only runs on the first display (/dev/fb0).
Is there any way to run an application on the second display (/dev/fb2) using "-platform eglfs"?

Best regards,

Johan

fludwig

Hi there!

I'm also trying to figure this out at the moment - did you have already success displaying something with eglfs on the second screen?

Thanks!
Florian

agocs

No, there is no such support in eglfs at the moment. It always uses /dev/fb0 and, in case of iMX6, binds the EGL display to that framebuffer.

I have created http://bugreports.qt-project.org/browse/QTBUG-36113 since this is definitely something that should be addressed.

fludwig

Oh perfect :) Thanks!

But at the moment it should be possible to use eglfs on the fb0 and linuxfb on a second screen or not?

agocs

That should be possible, yes.

agocs

I tried this today on my i.MX6 board and it worked well: eglfs was using fb0 (HDMI) while another app was running with -platform linuxfb:fb=/dev/fb2 and was displaying on the LCD.

henry10210

Hello, I am a QT newbie (just ran the pathstroke demo application running on my ARM target with -platform linuxfb). I skimmed through "Application with Qt Creator" by Ray Rischpater, but I still don't feel like I understand how to approach the multi-monitor, full screen Qt application. In particular, I am unsure whether this bug means that I cannot full-screen 2D paint to multiple monitors using a GPU, within ONE application, or whether this is just a performance issue, because you can always render to multiple screens--just slowly.

Any advice please?