Hi, Javier, On Sat, May 21, 2022 at 12:32 AM Javier Martinez Canillas <javierm@xxxxxxxxxx> wrote: > > On 5/20/22 17:19, Huacai Chen wrote: > > Hi, Javier, > > [snip] > > >> Conversely, if the sysfb_init() is executed first then the platform device > >> will be registered and latter when the driver's init register the driver > >> this will match the already registered device. > > Yes, you are right, my consideration is too complex. The only real > > problem is a harmless error "efifb: a framebuffer is already > > registered" when both efifb and the native display driver are > > built-in. > > > > But this shouldn't be a problem if you drop your register_gop_device() that > registers an "efi-framebuffer", since sysfb would either register a platform > device "simple-framebufer" or "efi-framebuffer", but never both. Those are > mutually exclusive. > > I think what's happening now is that sysfb is registering a "simple-framebuffer" > but your register_gop_device() function is also registering an "efi-framebuffer". No, I have already removed register_gop_device(). Now my problem is like this: 1, efifb (or simpledrm) is built-in; 2, a native display driver (such as radeon) is also built-in. Because efifb, radeon and sysfb are all in device_initcall() level, the order in practise is like this: efifb registered at first, but no "efi-framebuffer" device yet. radeon registered later, and /dev/fb0 created. sysfb_init() comes at last, it registers "efi-framebuffer" and then causes the error "efifb: a framebuffer is already registered". make sysfb_init() to be subsys_initcall_sync() can avoid this. Huacai > > -- > Best regards, > > Javier Martinez Canillas > Linux Engineering > Red Hat >
