How to enable Six overlays in Xavier ?

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
#1

I am trying to enable six overlays in Xavier like Jetson TX2 using below commands :-

sudo -s

cd /sys/class/graphics/fb0

echo 4 > blank

echo 0x0 > device/win_mask

echo 0x3f > device/win_mask

echo 0 > blank

But not able to enable six overlays.
I also find a way to enable six overlay via changing “win-mask=<0x3f>” in tegra194-p2822-disp.dtsi DTB file.
So, I want to know how to enable overlays in Xavier by using sysfs entry or Is DTB file change is the only option to enable overlays ?
I also seen 2 extra framebuffer node in Xavier, How I can use those /dev/fb1 and /dev/fb2 please suggest any reference for that.

Thanks

#2

I would expect that you could use the additional framebuffers by plugging displays into the USB-C connetors, and then running X windows displays on those nodes.
(The X server may automatically open displays for those nodes when they’re connected; I have not tried this)

#3

Hi,
Please, anyone, respond to my primary Query “How to enable Six overlays in Xavier?”. This query is very important for my further software development.

Thanks

#4

Sorry for late reply. I am checking if the debug node has something wrong.

Is the win-mask in DT working fine?

#5

BTW, did you remember to set win_mask to 0 for other 2 fb?

#6

Yes WayneWWW, I am able to access all Six overlays after DTB modification but when I am trying using sysfs not able to succeed.

When I am trying “echo 0x3f > device/win_mask” then observed error like:-
bash: echo: write error: Invalid argument

and dmesg says:-
[ 122.870220] tegradc 15200000.nvdisplay: win[2] already on fb1
I am not able to understand why this is happening when trying to enable overlays using sysfs.

Please suggest if any proper reason for above error log.

Thanks

#7

No, Currently I am not doing any experiments on fb1 & fb2, because I don’t know how to use them also primary framebuffer is fb0 so, my concentration on fb0 for enabling six overlays.
BTW fb1 and fb2 win-mask is 0xc and 0x30 respectivily in my case.

#8

Hi riteshkumar.p,

Please set fb1 and fb2 win_mask to 0x0 first, then set fb0 win_mask to 0x3f.
Then overlay=1~6 can run success without problem.

#9

Please follow the instruction shared by carolyuu. Thanks.

#10

Hi carolyuu & WayneWWW,
This is working. Thanks for the help.
I tried below commands and able to enable six overlays using sysfs.

sudo su

cd /sys/class/graphics/fb1

echo 0x0 > device/win_mask

cd /sys/class/graphics/fb2

echo 0x0 > device/win_mask

cd /sys/class/graphics/fb0

echo 4 > blank

echo 0x0 > device/win_mask

echo 0x3f > device/win_mask

echo 0 > blank