Re: build failure in linux-next: offb missing fb helpers

["Michal Suchánek" <msuchanek@suse.de>]

Hello,

On Sat, Nov 19, 2022 at 10:27:04PM +0900, Masahiro Yamada wrote:
> On Sat, Nov 19, 2022 at 3:20 PM Randy Dunlap <rdunlap@infradead.org> wrote:
> >
> > Hi--
> >
> > [adding Masahiro-san]
> >
> >
> > On 11/18/22 07:03, Michal Suchánek wrote:
> > > Hello,
> > >
> > > I am seeing these errors:
> > >
> > > [ 3825s]   AR      built-in.a
> > > [ 3827s]   AR      vmlinux.a
> > > [ 3835s]   LD      vmlinux.o
> > > [ 3835s]   OBJCOPY modules.builtin.modinfo
> > > [ 3835s]   GEN     modules.builtin
> > > [ 3835s]   GEN     .vmlinux.objs
> > > [ 3848s]   MODPOST Module.symvers
> > > [ 3848s]   CC      .vmlinux.export.o
> > > [ 3849s]   UPD     include/generated/utsversion.h
> > > [ 3849s]   CC      init/version-timestamp.o
> > > [ 3849s]   LD      .tmp_vmlinux.btf
> > > [ 3864s] ld: drivers/video/fbdev/offb.o:(.data.rel.ro+0x58): undefined
> > > reference to `cfb_fillrect'
> > > [ 3864s] ld: drivers/video/fbdev/offb.o:(.data.rel.ro+0x60): undefined
> > > reference to `cfb_copyarea'
> > > [ 3864s] ld: drivers/video/fbdev/offb.o:(.data.rel.ro+0x68): undefined
> > > reference to `cfb_imageblit'
> > >
> > > cfb_fillrect is provided by drivers/video/fbdev/core/cfbfillrect.c
> > >
> > > It is compiled when CONFIG_FB_CFB_FILLRECT
> > > drivers/video/fbdev/core/Makefile:obj-$(CONFIG_FB_CFB_FILLRECT)  += cfbfillrect.o
> > >
> > > drivers/video/fbdev/Makefile:obj-$(CONFIG_FB_OF)               += offb.o
> > > is compiled when CONFIG_FB_OF
> > >
> > > It selects CONFIG_FB_CFB_FILLRECT
> > > config FB_OF
> > >         bool "Open Firmware frame buffer device support"
> > >         depends on (FB = y) && PPC && (!PPC_PSERIES || PCI)
> > >         select APERTURE_HELPERS
> > >         select FB_CFB_FILLRECT
> > >         select FB_CFB_COPYAREA
> > >         select FB_CFB_IMAGEBLIT
> > >         select FB_MACMODES
> > >
> > > The config has FB_OF built-in and FB_CFB_FILLRECT modular
> > > config/ppc64le/vanilla:CONFIG_FB_CFB_FILLRECT=m
> > > config/ppc64le/vanilla:CONFIG_FB_CFB_COPYAREA=m
> > > config/ppc64le/vanilla:CONFIG_FB_CFB_IMAGEBLIT=m
> > > config/ppc64le/vanilla:CONFIG_FB_OF=y
> > >
> > > It only depends on FB which mut be built-in for FB_OF
> > > config FB_CFB_FILLRECT
> > >         tristate
> > >         depends on FB
> > >
> > > Is select in kconfig broken?
> > >
> > > Attachnig the config in question.
> >
> > The symbol info from xconfig says:
> >
> > Symbol: FB_CFB_FILLRECT [=m]
> > Type : tristate
> > Defined at drivers/video/fbdev/Kconfig:69
> > Depends on: HAS_IOMEM [=y] && FB [=y]
> > Selected by [m]:
> > [deleted]
> > - FB_OF [=y] && HAS_IOMEM [=y] && FB [=y]=y && PPC [=y] && (!PPC_PSERIES [=y] || PCI [=y]) && !DRM_OFDRM [=m]
> >
> > I don't see why the 'select' from (bool) FB_OF would leave FB_CFB_FILLRECT (and the others)
> > as =m instead of =y.
> >
> > Hopefully Masahiro can shed some light on this.
> >
> > --
> > ~Randy
> 
> 
> The reason is shown in your paste of help message:
> 
> "&& !DRM_OFDRM [=m]" downgrades it to "selected by m"
> 
> To aid this particular case, the following will select
> FB_CFB_FILLRECT=y.
> 
> 
> 
> 
> diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
> index 66f36b69e8f3..2bcf8627819f 100644
> --- a/drivers/video/fbdev/Kconfig
> +++ b/drivers/video/fbdev/Kconfig
> @@ -458,7 +458,7 @@ config FB_ATARI
>  config FB_OF
>         bool "Open Firmware frame buffer device support"
>         depends on (FB = y) && PPC && (!PPC_PSERIES || PCI)
> -       depends on !DRM_OFDRM
> +       depends on DRM_OFDRM != y
>         select APERTURE_HELPERS
>         select FB_CFB_FILLRECT
>         select FB_CFB_COPYAREA

Thanks for clarification.

This change fixess the config for me.

Michal


> Or, perhaps "depends on DRM_OFDRM = n"
> I do not know the intention of this dependency.
> 
> Recommendation is to use "depends on" instead of "select" though.
> 
> 
> 
> BTW, this is similar to what you asked before.
> 
> https://lore.kernel.org/linux-kbuild/e1a6228d-1341-6264-d97a-e2bd52a65c82@infradead.org/
> 
> 
> I tried to fix it in the past, but the issue was not as shallow as I
> had expected.
> I did not get around to revisiting this topic.
> 
> https://patchwork.kernel.org/project/linux-kbuild/patch/1543216969-2227-1-git-send-email-yamada.masahiro@socionext.com/
>