linux-kernel - Re: [PATCH] fbdev: simplefb: limit its use to DRM

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Date:   Mon, 19 Jul 2021 10:06:29 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Randy Dunlap <rdunlap@...radead.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        kernel test robot <lkp@...el.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Linux Fbdev development list <linux-fbdev@...r.kernel.org>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        Thomas Zimmermann <tzimmermann@...e.de>
Subject: Re: [PATCH] fbdev: simplefb: limit its use to DRM_SIMPLEDRM=n

Hi Randy,

On Mon, Jul 19, 2021 at 4:34 AM Randy Dunlap <rdunlap@...radead.org> wrote:
> When DRM_SIMPLEDRM=m, all of FB_CFB_{FILLRECT,COPYAREA,IMAGEBLIT} are =m,

Why does that happen?
FB_SIMPLE does select FB_CFB_*, so all of the latter should be builtin?
Do I need my morning coffee? I'm about to fetch it...

> causing undefined references in fbdev/simplefb.o.
>
> By restricting FB_SIMPLEFB to be set only when DRM_SIMPLEDRM is not set,
> the FB_CFB_* symbols are =y and the build completes without these
> undefined references.
>
> IOW, really "disable simplefb if simpledrm has been selected".

That does make sense, regardless of my question above ;-)

> or1k-linux-ld: drivers/video/fbdev/simplefb.o:(.rodata+0x2c): undefined reference to `cfb_fillrect'
> or1k-linux-ld: drivers/video/fbdev/simplefb.o:(.rodata+0x30): undefined reference to `cfb_copyarea'
> or1k-linux-ld: drivers/video/fbdev/simplefb.o:(.rodata+0x34): undefined reference to `cfb_imageblit'
>
> Fixes: 11e8f5fd223b ("drm: Add simpledrm driver")
> Signed-off-by: Randy Dunlap <rdunlap@...radead.org>

> --- linux-next-20210716.orig/drivers/video/fbdev/Kconfig
> +++ linux-next-20210716/drivers/video/fbdev/Kconfig
> @@ -2192,7 +2192,7 @@ config FB_HYPERV
>
>  config FB_SIMPLE
>         bool "Simple framebuffer support"
> -       depends on (FB = y) && !DRM_SIMPLEDRM
> +       depends on (FB = y) && DRM_SIMPLEDRM=n
>         select FB_CFB_FILLRECT
>         select FB_CFB_COPYAREA
>         select FB_CFB_IMAGEBLIT

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds