Changing HDMI resolution via command issue

[wangvictor]

Hi All,

I'm developing  Android 6 image on i.MX6 sabreSD DL.

Here I facing the problem.

Command line settings and kernel driver settings are all 1920X1080 HDMI.

Output show perfectly then.

When I try to change the resolution from FULL HD to 1280x720 by below command.

echo "S:1280x720p-60" > /sys/class/graphics/fb0/mode

Then output will not show as expect, It shows like below picture.

And if I try to change the command line from

bootargs console=ttymxc1,115200 init=/init video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24,bpp=32  video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off  vmalloc=256M androidboot.console=ttymxc1 consoleblank=0 androidboot.hardware=FA30H_HW100 cma=384M androidboot.selinux=disabled androidboot.dm_verity=disabled

to

bootargs console=ttymxc1,115200 init=/init video=mxcfb0:dev=hdmi,1280x720M@60,if=RGB24,bpp=32  video=mxcfb1:off video=mxcfb2:off video=mxcfb3:off  vmalloc=256M androidboot.console=ttymxc1 consoleblank=0 androidboot.hardware=FA30H_HW100 cma=384M androidboot.selinux=disabled androidboot.dm_verity=disabled

The output will show like below picture.

According to the red circle in the picture, I can't understand why there is black blank there.

In conclusion, two question for total.

1. Why the output shows strange while I change the resolution by command?
2. Why it will shows black blank if I change the resolution settings in command line?

Thanks in Advanced!

[xvsd_247]

I am stuck on the first question too. Do you have any progress?

[art]

There seems to be some wrong interaction between the monitor and the board's HDMI interface. Does the monitor itself support the 1280x720 resolution? Please check. Also, try some other monitor.

Another possible reason is wrong logical display density setting when you set lower resolution. For details, please refer to the Section 20 "How do I configure the logical display density?" of the attached document.

Have a great day,
Artur