linux-kernel - Re: [PATCH v2 1/2] fbdev: Split frame buffer support in FB and FB

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Date:   Sun, 02 Jul 2023 12:19:37 +0200
From:   Javier Martinez Canillas <javierm@...hat.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Arnd Bergmann <arnd@...db.de>
Cc:     linux-kernel@...r.kernel.org,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Borislav Petkov <bp@...en8.de>,
        Daniel Vetter <daniel@...ll.ch>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "H. Peter Anvin" <hpa@...or.com>, Helge Deller <deller@....de>,
        Ingo Molnar <mingo@...hat.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Sam Ravnborg <sam@...nborg.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org,
        x86@...nel.org
Subject: Re: [PATCH v2 1/2] fbdev: Split frame buffer support in FB and
 FB_CORE symbols

Geert Uytterhoeven <geert@...ux-m68k.org> writes:

> Hi Arnd,
>

[...]

>>
>> That would leave CONFIG_FB_DEVICE as the only user visible option
>> for DRM-only configs, which is slightly odd for the menuconfig,
>> so I still wonder if that could be done differently.
>>
>> Is there actually a point in configurations for kernels with FB=y,
>> DRM=n and FB_DEVICE=n? If we don't expect that to be a useful
>> configuration, an easier way would be to have CONFIG_FB turn it
>> on implicitly and instead have a user-visible Kconfig option
>> below CONFIG_DRM_FBDEV_EMULATION that allows controlling the
>> creation of /dev/fb*.
>
> Such a combination would allow the user to still have a text console
> on a legacy fbdev, while not having to worry about possible security
> ramifications of providing fbdev userspace access.
>

Exactly, it may be a possible combination. Not sure how useful what would
be in practice but we shouldn't restrict that IMO.

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat