This is also a problem in the documentation. You already fixed it, not related to your problem. Looks like this name error is being spread in all compiled kernel in all cpi images. The CPI kernel makes a wrong reference to the driver name sun4i_drm whereas mesa driver install sun4i-drm. This force us to manually create a symbolic link or copy sun4i-drm to sun4i_drm which is a very bad thing to do for the lifespan of the device. In the future, when new people try to use the system they will get frustrated, as you did and I did. In some years this information (creating this symb links) will be less known.
If you go to the patch file for kernel 5.2 at https://raw.githubusercontent.com/clockworkpi/Kernel/master/v0.4/52rc4.patch
You will see this:
diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.c b/drivers/gpu/drm/sun4i/sun4i_drv.c
index 3ff73998d841..1def6aa2a071 100644
--- a/drivers/gpu/drm/sun4i/sun4i_drv.c
+++ b/drivers/gpu/drm/sun4i/sun4i_drv.c
@@ -42,7 +42,7 @@ static struct drm_driver sun4i_drv_driver = {
/* Generic Operations */
.fops = &sun4i_drv_fops,
- .name = "sun4i-drm",
+ .name = "sun4i_drm",
.desc = "Allwinner sun4i Display Engine",
.date = "20150629",
.major = 1,
This is the cause of the problem. Maybe in the past they needed to do it to get lima working, but it is not necessary anymore. If you remove this part and reapply the patch you don’t need to create the symb link after.
I also found another error related to the kernel, the power button. I could bring the power button to do soft poweroff just removing some patches that were applied to the kernel. For me, this is a good feature, you don’t need to navigate in the menu to switch off, just press the power button once and it will send a poweroff to the OS as you could do to the PC:
I wouldn’t be surprised if more of these tiny things are inside the SO that prevents us to get an updated system since we don’t know what else was changed in the SO to make everything working.