topic Re: i.mx6 Yocto Clone Display /dev/fb0 to /dev/fb2 in i.MX Processors

i.mx6 Yocto Clone Display /dev/fb0 to /dev/fb2

matthiasalbrech — Thu, 22 Mar 2018 11:34:28 GMT

Hi,

I use I.mx6 with yocto and try to clone/mirror my Display. I have an internal lvds Display and an USB-DVI Adapter (DisplayLink). The Displaylink driver works and after plug it in /dev/fb2 appears. Its possible to copy data in fb2 and it appears on the display. But I want to mirror my lvds screen.

First I tried it with Xorg and for the first test I copied in .conf:

Section "Device"
Identifier "i.MX Accelerated Framebuffer Device-0"
Driver "fbdev"
Option "fbdev" "/dev/fb0"
Option "vivante_fbdev" "/dev/fb0"
Option "HWcursor" "false"
EndSection

Section "Device"
Identifier "i.MX Accelerated Framebuffer Device-1"
Driver "fbdev"
Option "fbdev" "/dev/fb2"
Option "vivante_fbdev" "/dev/fb2"
Option "HWcursor" "false"
Option "NoAccel" "True"
EndSection

Section "Monitor"
Identifier "Monitor0"
EndSection

Section "Monitor"
Identifier "Monitor1"
EndSection

Section "Screen"
Identifier "Scr0"
Monitor "Monitor0"
Device "i.MX Accelerated Framebuffer Device-0"
EndSection

Section "Screen"
Identifier "Scr1"
Monitor "Monitor1"
Device "i.MX Accelerated Framebuffer Device-1"
EndSection

Section "ServerFlags"
Option "Xinerama" "true"
EndSection

Section "ServerLayout"
Identifier "Default Layout"
Screen "Scr0" 0 0
Screen "Scr1" RightOf "Scr0"
EndSection

============

With that configuration I can expand the display. But I need the vivante driver, not fbdev (as I know, vivante doesn't support dual display mode?). And its not possible to clone the display when I change the ServerLayout. So my thought was to develop a small program to copy fb0 to fb2. Are there any solutions how to do that? Or do you have any completely different idea how to clone the display?

thanks,

Matthias

Re: i.mx6 Yocto Clone Display /dev/fb0 to /dev/fb2

igorpadykov — Thu, 22 Mar 2018 23:16:42 GMT

Hi Matthias

one can look at suggestions provided on

i.mx6q Enable Dual Display of Ubuntu

Cloning a display

Best regards
igor
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Re: i.mx6 Yocto Clone Display /dev/fb0 to /dev/fb2

matthiasalbrech — Thu, 29 Mar 2018 10:00:27 GMT

Hi,

thanks. But it doesn't work. I read that in xorg.conf I have to use vivante for one framebuffer and for the other fbdev (it seems that "vivante" not support two display? :i.mx6q Enable Dual Display of Ubuntu ). But that doesn't work for me.

I would like it to copy one framebuffer to the other (/dev/fb0 to /dev/fb2). But if I do a simple "cat /dev/fb0 > /dev/fb2" (or use my efficient c-code with mmap) the display shows a strange picture (see attachment). Do you know why it shows something like that? Or do you where I can get informations about that?

thanks,

Matthias