Comment # 8 on bug 1140581 from Chaoyang Qin

(In reply to Nicolas Patricio Saenz Julienne from comment #7)
> (In reply to Chaoyang Qin from comment #0)
> > I have a WaveShare 3.5in GPIO RPi LCD(A),According wiki: HCL:Raspberry Pi3
> > LCD follow steps modified extraconfig.txt added dtoverlay=rpi-display ,but
> > at reboot,the touchscreen is Blank screen only,but backlight is on.
> 
> Was that the only overlay you where using?

dtoverlay=rpi-display
According HCL...