Re: [REGRESSION] boot-screen override by "34db50e55656 efifb: Copy the ACPI BGRT"

[Hans de Goede]

Hi,

On 03-09-18 17:11, David Herrmann wrote:
> Hey
>
> On Mon, Sep 3, 2018 at 4:47 PM Hans de Goede <hdegoede@xxxxxxxxxx> 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!

Ok, I just send out a patch for this with you in the Cc.

Sorry for taking a bit long to write the patch.

Regards,

Hans