Comment # 39 on bug 1140581 from Nicolas Patricio Saenz Julienne

(In reply to Chaoyang Qin from comment #38)
> (In reply to Nicolas Patricio Saenz Julienne from comment #37)
> > (In reply to Chaoyang Qin from comment #35)
> > > (In reply to Nicolas Patricio Saenz Julienne from comment #33)
> > > > Hi Chaoyang Qin, there was still a fix to be done. Keep in mind that the
> > > > display driver is in the staging tree and the quality is not assured.
> > > > 
> > > > Please install this kernel:
> > > > https://download.opensuse.org/repositories/home:/nsaenzjulienne:/fbtft-test/
> > > > ARM/aarch64/kernel-default-5.1.16-3.1.g598180e.aarch64.rpm
> > > > 
> > > > And use the overlay I'll attach following this message. To do so you have
> > > > to: copy the file into '/boot/efi/overlays', and replace
> > > > dtoverlay=rpi-display with dtoverlay=waveshare35a in your config.txt.
> > > 
> > > Screen go black ,and imageview test show load failed.
> > 
> > Please try the X11 test:
> > https://github.com/notro/fbtft/wiki/Framebuffer-use#x-server
> > 
> > Apart from running startx, also try restarting the device after creating the
> > configuration file.
> 
> Still unable,X server not init?
> dmesg output stopped at 43 sec

Still black output? did you see a console output on the display while booting?

If not, let's try something more drastic, do:

cat /dev/urandom > /dev/fb1

You should see random colored pixels.