Re: [PATCH] drm: fix up fbdev Kconfig defaults

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Hi

Am 12.09.23 um 09:14 schrieb Geert Uytterhoeven:
[...]
> > --- a/drivers/gpu/drm/Kconfig
> > +++ b/drivers/gpu/drm/Kconfig
> > @@ -135,7 +135,7 @@ config DRM_FBDEV_EMULATION
> >          bool "Enable legacy fbdev support for your modesetting driver"
> >          depends on DRM
> >          select FRAMEBUFFER_CONSOLE_DETECT_PRIMARY if FRAMEBUFFER_CONSOLE
> > -       default y
> > +       default FB
>
> While this is true for existing configs, it is no longer true in general,
> as DRM_FBDEV_EMULATION is no longer related to FB.

Would it make sense to make FRAMEBUFFER_CONSOLE an independent option 
and have FBDEV_EMULATION depend on it? Something like this:

FRAMEBUFFER_CONSOLE
	depends on DRM || FB
	select FB_CORE

FBDEV_EMULATION
	depends on DRM
	depends on FRAMEBUFFER_CONSOLE
	default y

So if any graphics subsystems are enabled, FRAMEBUFFER_CONSOLE is 
select-able. But for DRM, FBDEV_EMULATION disables the console. That 
option remains more for historical reasons than actual usefulness.

Best regards
Thomas

> >          help
> >            Choose this option if you have a need for the legacy fbdev
> >            support. Note that this support also provides the linux console
> > diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
> > index b575cf54174af..83c2d7329ca58 100644
> > --- a/drivers/video/console/Kconfig
> > +++ b/drivers/video/console/Kconfig
> > @@ -74,6 +74,7 @@ config DUMMY_CONSOLE_ROWS
> >   config FRAMEBUFFER_CONSOLE
> >          bool "Framebuffer Console support"
> >          depends on FB_CORE && !UML
> > +       default DRM_FBDEV_EMULATION
>
> Sounds good to me, although it looks a bit strange at first sight
> (FRAMEBUFFER_CONSOLE defaults to n on a system with real fbdev, but
> y on emulated fbdev?).
> So this is the fix for commit a5ae331edb02b ("drm: Drop select
> FRAMEBUFFER_CONSOLE for DRM_FBDEV_EMULATION").
>
> >          select VT_HW_CONSOLE_BINDING
> >          select CRC32
> >          select FONT_SUPPORT
> > diff --git a/drivers/video/fbdev/core/Kconfig b/drivers/video/fbdev/core/Kconfig
> > index 114cb8aa6c8fd..804c2bec9b43c 100644
> > --- a/drivers/video/fbdev/core/Kconfig
> > +++ b/drivers/video/fbdev/core/Kconfig
> > @@ -28,7 +28,7 @@ config FIRMWARE_EDID
> >   config FB_DEVICE
> >          bool "Provide legacy /dev/fb* device"
> >          depends on FB_CORE
> > -       default y
> > +       default FB
>
> Changing this means possibly causing regressions on systems running
> an fbdev userspace.
>
> >          help
> >            Say Y here if you want the legacy /dev/fb* device file and
> >            interfaces within sysfs anc procfs. It is only required if you
>
> Gr{oetje,eeting}s,
>
>                          Geert

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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