Regarding i.MX6DQ display blanking/unblanking with L3.0.101.

[satoshishimoda]

Hi community,

I have some questions about i.MX6DQ Linux BSP (L3.0.101) frame buffer.

[Q1]

You know /dev/fb0 is unblanked when i.MX6DQ Linux BSP (L3.0.101_4.1.1) is boot, but /dev/fb2 is blanked if fb0=ldb and fb2=hdmi.

(with 'video=mxcfb0:dev=ldb video=mxcfb1:dev=hdmi,1920x1080M@60,if=RGB' boot parameter)

Then, we want to be unblanked both display (lvds and hdmi) when boot i.MX6DQ Linux BSP, not only /dev/fb0.

I checked Dual display LVDS + HDMI on iMX6 , but it seems to has been unresolved.

So what should we modify to realize it?

Change a device driver? or a boot parameter?

[Q2]

We can unblank a hdmi display with the following command.

  echo 0 > /sys/class/graphics/fb2/blank

After unblanking both display (/dev/fb0:lvds, /dev/fb2:hdmi) by the above command, I executed the following command.

  echo 1 > /sys/class/graphics/fb0/blank

Then, not only fb2 (hdmi display) was blanked but also fb0 (lvds display).

How should we do to blank only fb2 in this case?

Best Regards,

Satoshi Shimoda

[qiang_li-mpu_se · Accepted solution]

For Q1, you can add "echo 0 > /sys/class/graphics/fb2/blank" at the end of rootfs//etc/rc.d/rc.local

For Q2, it is more like backlight issue. You can modify "drivers\video\backlight\pwm_bl.c", function pwm_backlight_check_fb(), just return 0 from it.