I.MX6 Ubuntu 13.04 Debugging GPU Acceleration

You've probably reached here because your having problems getting the rootfs in my previous post to work for X11. So here some debugging tips to help you out:

1. The kernel I used is 4.1.0  and can be found in my repo and is a branch of the FSL repo. An additional patch to set the correct busid for the vivante driver may need to be made if not present in the kernel:

--- a/drivers/gpu/drm/vivante/vivante_drv.c
+++ b/drivers/gpu/drm/vivante/vivante_drv.c
@@ -55,7 +55,7 @@

#include "drm_pciids.h"

-static char platformdevicename[] = "Vivante GCCore";
+static char platformdevicename[] = "Vivante GCCore:00";
static struct platform_device *pplatformdev;

static struct drm_driver driver = {

Here is my  defconfig (I'm compiling for a custom board). Note: the FSL patch (ENGR00264288-1) to upgrade the Vivante libraries to 4.6.9p12.

2. Once you have a booting kernel, you should first test that kernel works against the Vivante framebuffer libraries. To do this we simply switch to the fb libraries (need to be root):

cd /usr/lib
rm libEGL.so.1.0 libEGL.so.1 libEGL.so
ln -s libEGL-fb.so libEGL.so.1.0
ln -s libEGL-fb.so libEGL.so.1
ln -s libEGL-fb.so libEGL.so 

rm libGAL.so
ln -s libGAL-fb.so libGAL.so

rm libVIVANTE.so 
ln -s libVIVANTE-fb.so libVIVANTE.so 

Now test with one of the Vivante tutorial examples (pick any of the tutorials)

cd /root/gpu-viv-bin-mx6q-3.5.7-1.0.0-alpha.2-hfp/opt/viv_samples/vdk
./tutorial7

If the tutorial doesn't run it may indicate there is a mismatch between the kernel Vivante code and the libraries or the Vivante libraries may be missing a dependency.

3. If everything is fine with the framebuffer libraries we can now switch back to x11:

cd /usr/lib

rm libEGL.so.1.0 libEGL.so.1 libEGL.so
ln -s libEGL-x11.so libEGL.so.1.0
ln -s libEGL-x11.so libEGL.so.1
ln -s libEGL-x11.so libEGL.so 

rm libGAL.so
ln -s libGAL-x11.so libGAL.so

rm libVIVANTE.so 
ln -s libVIVANTE-x11.so libVIVANTE.so 

Now reboot.

4. Before we test with X, we need to check that kernel vivante/drm modules are loaded:

root@ubuntu-imx6:~# lsmod

Module                  Size  Used by

vivante                  947  1 

drm                   137567  2 vivante

If the modules aren't loaded then X will revert to software rendering because the device /dev/dri/card0 does not exist. The loading of the module is configured in /etc/modules

5. I suggest starting a simple X server to test that the Vivante drivers get correctly loaded:

startx &

The output of the /var/log/Xorg.0.log should be similar to this. If errors are reported it may be because:

1. The vivante kernel module didn't load

2. Check the exa driver is present /usr/lib/xorg/modules/drivers/vivante_drv.so

3. Least likely, missing permissions on the gpu device, these should be setup in  /etc/udev/rules.d/10-imx.rules.

6. Validate the output of glxinfo and es2_info (they should show the presence of the Vivante drivers):

export DISPLAY=:0

glxinfo

es2_info

If you are not seeing "OpenGL renderer string: GC2000 Graphics Engine" and/or "EGL_VENDOR = Vivante Corporation" in the output then it may be possible that the mesa libraries are being picked up. If the directories /usr/lib/arm-linux-gnueabihf/mesa and/or /usr/lib/arm-linux-gnueabihf/mesa-egl are present then move these to another location. They shouldn't be present on my rootfs unless the mesa packages were reinstalled.