[PATCH V2] drivers/firmware: Move sysfb_init() from device_initcall to subsys_initcall_sync

[Huacai Chen]

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@redhat.com/

Signed-off-by: Huacai Chen <chenhuacai at loongson.cn>
---
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