Re: [PATCH v2 3/3] efi: earlycon: Add support for generic framebuffers and move to console subsystem

From: "Arnd Bergmann" <arnd@arndb.de>
To: "Daniel Vetter" <daniel@ffwll.ch>,
	"Markuss Broks" <markuss.broks@gmail.com>
Cc: linux-fbdev@vger.kernel.org, linux-efi@vger.kernel.org,
	linux-doc@vger.kernel.org, Tony Lindgren <tony@atomide.com>,
	dri-devel@lists.freedesktop.org,
	Wei Ming Chen <jj251510319013@gmail.com>,
	phone-devel@vger.kernel.org, Jiri Slaby <jirislaby@kernel.org>,
	Ard Biesheuvel <ardb@kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Damien Le Moal <damien.lemoal@opensource.wdc.com>,
	Javier Martinez Canillas <javierm@redhat.com>,
	linux-serial@vger.kernel.org, Borislav Petkov <bp@suse.de>,
	Kees Cook <keescook@chromium.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	~postmarketos/upstreaming@lists.sr.ht,
	Michal Suchanek <msuchanek@suse.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	linux-kernel@vger.kernel.org,
	Thomas Zimmermann <tzimmermann@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Helge Deller <deller@gmx.de>
Subject: Re: [PATCH v2 3/3] efi: earlycon: Add support for generic framebuffers and move to console subsystem
Date: Wed, 07 Sep 2022 10:22:03 +0200	[thread overview]
Message-ID: <e2e2a0c7-d859-4255-94b6-b030aa9dc277@www.fastmail.com> (raw)
In-Reply-To: <YxfBGDg6YkIQ6Wzq@phenom.ffwll.local>

On Tue, Sep 6, 2022, at 11:52 PM, Daniel Vetter wrote:
> On Sat, Aug 06, 2022 at 07:32:24PM +0300, Markuss Broks wrote:
>
> Ok I have a more fundamental issue with this than the lack of proper patch
> splitting I mentioned in the other thread.
>
> This is the wrong place.
>
> drivers/video/console is about the various vt console implementations,
> which supply a struct consw to con_register_driver.

You are right, that was my mistake. The original patch was for
drivers/video/fbdev/, and I suggested moving it out of there because
it does not depend on the fbdev subsystem, but clearly my suggestions
of drivers/video/console was equally wrong.

> This otoh is an (early) kernel/printk console implemented using struct
> console. Totally different thing, and really shouldn't end up in
> drivers/video/console imo. Somewhere in drivers/firmware might still be
> the best place, the sysfb stuff is also there. Maybe
> drivers/firmware/sysfb_earlycon.c?

drivers/firmware/ is better but doesn't sound great to me either,
since one important thing the patch does is to not make it depend
on EFI firmware or BIOS style screen_info any more. 

Maybe drivers/tty/earlycon_simplefb.c would work better, keeping
it close to the earlycon base support in drivers/tty/serial/,
the vt console and the old simplefb driver/, without tying to too
closely to fbdev of UEFI.

     Arnd