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From:   David Herrmann <dh.herrmann@gmail.com>
Date:   Mon, 3 Sep 2018 17:11:23 +0200
Message-ID: <CANq1E4TiMSY=udGJWZoDzMhdsRjC==QCRFPO+Oja7KoyBX-6fg@mail.gmail.com>
Subject: Re: [REGRESSION] boot-screen override by "34db50e55656 efifb: Copy
 the ACPI BGRT"
To:     Hans de Goede <hdegoede@redhat.com>
Cc:     Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-fbdev@vger.kernel.org, linux-efi@vger.kernel.org,
        dri-devel@lists.freedesktop.org
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Hey

On Mon, Sep 3, 2018 at 4:47 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi,
>
> On 03-09-18 16:16, Bartlomiej Zolnierkiewicz wrote:
> >
> > Hi,
> >
> > On Monday, September 03, 2018 03:23:38 PM David Herrmann wrote:
> >> Hey
> >>
> >> Since this commit:
> >>
> >>      34db50e55656 efifb: Copy the ACPI BGRT
> >>
> >> the kernel will override boot-splashs unasked. This breaks the
> >> graphical boot-process on our setups. In particular, we have a setup
> >> where an efi-boot-entry draws the early boot-splash on-screen, then
> >> hands-over to the linux-kernel + initrd. The boot-splash daemon in the
> >> initrd then takes over control of possible animations.
> >>
> >> With the mentioned commit compiled in, the kernel will redraw the
> >> firmware logo on screen at a random time without any way to intervene.
> >
> > You have CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER=y (the deferred
> > console takeover support introduced in v4,19-rc1). I assume that this
> > is intended?
> >
> >> What is the intention of this commit? Why is the kernel re-drawing the
> >> firmware logo unasked? If someone during the boot-process draws
> >> content on the screen, I would prefer if the kernel does not clear
> >> that on driver load.
> >
> > +/*
> > + * If fbcon deffered console takeover is configured, the intent is for the
> > + * framebuffer to show the boot graphics (e.g. vendor logo) until there is some
> > + * (error) message to display. But the boot graphics may have been destroyed by
> > + * e.g. option ROM output, detect this and restore the boot graphics.
> > + */
> > +#if defined CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER && \
> > +    defined CONFIG_ACPI_BGRT
> > ...
> > +static void efifb_show_boot_graphics(struct fb_info *info)
> > ...
> > +#else
> > +static inline void efifb_show_boot_graphics(struct fb_info *info) {}
> > +#endif
> >
> >> Can we either provide an option to disable this feature, or revert the commit?
> >
> > Hans?
>
> We use the ACPI bgrt extension to get the logo to draw and then
> draw it since some devices rely on the OS to draw it and otherwise we
> just end up with a blackscreen when doing silent / flickerfree boot.
>
> Ideally you would be able to get your vendor to put the logo in firmware
> in the ACPI bgrt extension, then you also do not need to play any tricks
> with an EFI binary drawing your own logo. But I can understand if you don't
> have control over this, so you need to do this with the EFI binary trick.
>
> I can also understand that you want to use deferred console takeover
> in a setup like yours to avoid fbcon messing up what is on the display
> during boot, that is exactly what it is for. So I think a reasonable
> approach here is to add a kernel commandline option, say:
>
> video=efifb:nobgrt
>
> David, would that work for you?

That would be perfect!

Thanks
David