AnsweredAssumed Answered

i.Mx6Q frame buffer 2 issue

Question asked by Thai Dao on Sep 12, 2014
Latest reply on Sep 22, 2014 by Thai Dao

Hello everyone,

 

I got some issues with fb2.

Step 1: Show ring buffer infomation about mxc

dmesg | grep mxc_sdc


output:

mxc_sdc_fb mxc_sdc_fb.0: register mxc display driver lcd
mxc_sdc_fb mxc_sdc_fb.1: register mxc display driver hdmi
mxc_sdc_fb mxc_sdc_fb.2: register mxc display driver ldb
mxc_sdc_fb mxc_sdc_fb.3: register mxc display driver ldb


 

that mean hdmi is port is mapped to frame buffer 1

Step 2: Show frame buffer infor

cat /sys/class/graphics/fb1/modes


Output:

U:240x320p-60


Maybe, it's strange

I also checkout fb2 mode

cat /sys/class/graphics/fb2/modes


 

Output:

V:1280x1024p-60
V:1024x768p-60
U:1280x720p-120
U:1280x720p-100
U:1920x1080p-30
U:1920x1080p-25
U:1920x1080p-24
U:1920x1080p-50
U:1440x576p-50
U:1440x576p-50
U:1440x288p-50
U:1440x288p-50
U:1280x720p-50
U:720x576p-50
U:720x576p-50
U:1920x1080p-60
U:1440x480p-60
U:1440x480p-60
U:1440x240p-60
U:1440x240p-60
U:1280x720p-60
U:720x480p-60
U:720x480p-60
U:640x480p-60


I guess fb2 is frame buffer for hdmi port

Step 3: I rebuild fb-test app to test frame buffer

fb 0 worked well. We can display image on LCD and DVI port at the same time.(DVI and LCD use IPU1_DISP0)

fb 1 or 2 did not work. No thing displayed on screen

Test procedure

export DISPLAY=:2                                    //(or 0,1) export fb to user space ???
echo 0>/sys/class/graphics/fb2/blank          //unblank screen
./fb-test 2                                                     //run test application with fb2


 

My system

uname -a
Linux devel 3.0.35 #805 SMP Thu Apr 24 17:12:39 IDT 2014 armv7l GNU/Linux


 

what's is wrong in here?

 

Thank all,

Thaidao

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