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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <5a667be9-d2cb-d8fd-d321-b35e673b237e@infradead.org>
Date:   Mon, 19 Jul 2021 13:03:43 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Masahiro Yamada <masahiroy@...nel.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

On 7/19/21 1:06 AM, Geert Uytterhoeven wrote:
> 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...

Hi Geert,

I have no idea why this happens. It feels like a kconfig bug to me.

>> 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
> 


-- 
~Randy