iMX6SX: Removing GPU from Yocto build

[davidpatton]

We have a current board using an i.MX6SX with a GPU. We are developing a new board with an i.MX6SX, very similar to the previous board, but without the GPU.

In our .bb file we removed the "xf86-video-imx-vivante" line, but this doesn't appear to do much. The kernel still builds the GPU driver module (galcore.ko) which of coarse causes the kernel boot to fail, so I by-hand removed that file from the root file system. But then the xorg.conf file still expects the GPU:

Section "Device"
Identifier "i.MX Accelerated Framebuffer Device"
Driver "vivante"
Option "fbdev" "/dev/fb0"
Option "vivante_fbdev" "/dev/fb0"
Option "HWcursor" "false"
Option "DisplayEngine" "pxp"
EndSection

Section "ServerFlags"
Option "BlankTime" "0"
Option "StandbyTime" "0"
Option "SuspendTime" "0"
Option "OffTime" "0"
EndSection

I'm certain there are more instances of the GPU still being present but I gave up after 2 as it just seemed like an endless task.

There has got to be a way to completely remove the GPU from a Yocto build, but I cannot find any instructions on how to do this. Can someone please help me?!

Thanks...

[Bio_TICFSL]

Hello davidpaton,

The fact is for use X11 you need gpu, however the yocto itself take the MX6SX as it have GPU. So I recommend to use MX6UL but this will decrease the speed of the clock. Or you can take the yocto community and disable gpu from the kernel itslef.

Regards

[davidpatton]

Our original prototype board had an i.MX6SX without a GPU, and ran X11/Chromium but the performance of the LCD touchscreen was very bad. We thought we would try an i.MX6SX with a GPU but the performance did not increase. So we are now going back to an i.MX6SX without a GPU and using X11/GTK.

If I remove the kernel GPU module and change the xorg.cong file to:

Section "Device"
Identifier "Kernel Framebuffer Device"
Driver "fbdev"
Option "fbdev" "/dev/fb0"
EndSection

Section "ServerFlags"
Option "BlankTime" "0"
Option "StandbyTime" "0"
Option "SuspendTime" "0"
Option "OffTime" "0"
EndSection

Everything works fine. Since I can get an i.MX6SX with or without a GPU, and X11 runs on both, I should be able to specify whether the GPU is present or not for a Yocto build even when including X11.

[Bio_TICFSL]

Hello,

You can check GPU status with via its sysfs entry:

# cat /sys/kernel/debug/gc/idle
Start: 5217156788 ns
End: 28642408610 ns
On: 21105480 ns
Off: 22775044156 ns
Idle: 0 ns
Suspend: 629102186 ns

If you received nothing in the console you have the GPU disable.

Regards

[Bio_TICFSL]

You can check GPU status with via its sysfs entry:

# cat /sys/kernel/debug/gc/idle
Start: 5217156788 ns
End: 28642408610 ns
On: 21105480 ns
Off: 22775044156 ns
Idle: 0 ns
Suspend: 629102186 ns