Consider a configuration like this: 1, efifb (or simpledrm) is built-in; 2, a native display driver (such as radeon) is also built-in. As Javier said, this is not a common configuration (the native display driver is usually built as a module), but it can happen and cause some trouble. In this case, since 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 an error message "efifb: a framebuffer is already registered". Make sysfb_init() to be subsys_ initcall_sync() can avoid this. And Javier Martinez Canillas is trying to make a more general solution [1]. However, this patch still makes sense because it can make the screen display as early as possible (We cannot move to subsys_initcall, since sysfb_init() should be executed after PCI enumeration). [1] https://lore.kernel.org/all/20220607182338.344270-1-javierm@xxxxxxxxxx/ Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx> --- V2: Update commit messages. drivers/firmware/sysfb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c index 2bfbb05f7d89..aecf91517e54 100644 --- a/drivers/firmware/sysfb.c +++ b/drivers/firmware/sysfb.c @@ -80,4 +80,4 @@ static __init int sysfb_init(void) } /* must execute after PCI subsystem for EFI quirks */ -device_initcall(sysfb_init); +subsys_initcall_sync(sysfb_init); -- 2.27.0
