[PATCH] drm/Makefile: Move tiny drivers before native drivers

[Huacai Chen]

Hi, Javier,

On Mon, Dec 11, 2023 at 5:17 PM Javier Martinez Canillas
<javierm at redhat.com> wrote:
>
> Huacai Chen <chenhuacai at kernel.org> writes:
>
> > Hi, Javier,
> >
> > On Mon, Dec 11, 2023 at 4:33 PM Javier Martinez Canillas
> > <javierm at redhat.com> wrote:
> >>
> >> Huacai Chen <chenhuacai at kernel.org> writes:
> >>
> >> Hello Huacai,
> >>
> >> > Hi, Javier,
> >> >
> >> > On Wed, Nov 8, 2023 at 4:24 PM Javier Martinez Canillas
> >> > <javierm at redhat.com> wrote:
> >> >>
> >> >> Hello,
> >> >>
> >> >> On Wed, Nov 8, 2023 at 9:14 AM Thomas Zimmermann <tzimmermann at suse.de> wrote:
> >> >> >
> >> >> > Hi,
> >> >> >
> >> >>
> >> >> [...]
> >> >>
> >> >> >
> >> >> > Relying on linking order is just as unreliable. The usual workaround is
> >> >> > to build native drivers as modules. But first, please investigate where
> >> >> > the current code fails.
> >> >> >
> >> >>
> >> >> I fully agree with Thomas here. This is just papering over the issue.
> >> >>
> >> >> I'll read the lengthy thread now to see if I can better understand
> >> >> what's going on here.
> >> > Have you understood enough now? I really don't want the original patch
> >> > to be reverted.
> >> >
> >>
> >> I discussed this with Thomas but we didn't fully understand what was going
> >> on. In theory, it should work since the native driver should disable sysfb
> >> and remove the registered platform device. But it seems that this does not
> >> happen for Jaak and others who reported the same issue.
> >>
> >> Something that we noticed is that PCI fixups happen in fs_initcall_sync()
> >> and since the sysfb_init() should happen after the PCI subsystem for EFI
> >> quirks, we think that at least should be moved after that initcall level.
> >>
> >> That means rootfs_initcall() onwards, and that takes it almost at the same
> >> before your patch. The safest would be to move sysfb_init() to initcall
> >> device_initcall_sync() and make sure that happens after all the native DRM
> >> drivers, since module_init() happens at device_initcall().
> >>
> >> I think that Thomas meant to send a patch to do that change.
> > Thank you very much. I guess things may be like this:
> > i915 init at first, then simpledrm init in parallel and finished
> > before i915 call sysfb_disable(), so in my previous reply I provide a
> > debug patch for Jaak to see what happens.
> >
>
> Yes, specially with async probing although neither i915 nor simpledrm use
> it right now AFAICT.
>
> Is still unclear to me what's going on in this particular case, although
> moving it to device_initcall_sync() seems to be the correct thing to do
> regardless of this issue.
But that cannot "make the screen display as early as possible". Maybe
we can wait for Jaak's result.

Huacai

>
> --
> Best regards,
>
> Javier Martinez Canillas
> Core Platforms
> Red Hat
>