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

[Huacai Chen]

Hi, Javier,

On Sat, Jul 2, 2022 at 7:05 PM Javier Martinez Canillas
<javierm at redhat.com> wrote:
>
> Hello Huacai,
>
> Thanks a lot for your patch.
>
> On 7/2/22 11:04, Huacai Chen wrote:
> > 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/
> >
>
> Note that this series already landed, so you might want to refer the
> relevant commit sha-1 instead, i.e:
>
> commit 873eb3b11860 ("fbdev: Disable sysfb device registration when
> removing conflicting FBs").
OK, I'll update the commit message again and send V3.

Huacai
>
> > 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);
>
> I agree with the change and makes sense to me.
>
> Reviewed-by: Javier Martinez Canillas <javierm at redhat.com>
>
> --
> Best regards,
>
> Javier Martinez Canillas
> Linux Engineering
> Red Hat
>