Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230707095415.1449376-1-arnd@kernel.org> <20230707095415.1449376-3-arnd@kernel.org>
In-Reply-To: <20230707095415.1449376-3-arnd@kernel.org>
From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Fri, 7 Jul 2023 13:33:24 +0200
Message-ID: <CACRpkdbiDUomH8HLkk_jyJZYc+mEmRaFL8-JasDmd=ooSB62Qw@mail.gmail.com>
Subject: Re: [PATCH 3/4] dummycon: limit Arm console size hack to footbridge
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Thomas Zimmermann <tzimmermann@suse.de>, javierm@redhat.com,
        linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Russell King <linux@armlinux.org.uk>,
        dri-devel@lists.freedesktop.org, Ard Biesheuvel <ardb@kernel.org>,
        Helge Deller <deller@gmx.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
        linux-arm-kernel@lists.infradead.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Fri, Jul 7, 2023 at 11:56=E2=80=AFAM Arnd Bergmann <arnd@kernel.org> wro=
te:

> From: Arnd Bergmann <arnd@arndb.de>
>
> The dummycon default console size used to be determined by architecture,
> but now this is a Kconfig setting on everything except ARM. Tracing this
> back in the historic git trees, this was used to match the size of VGA
> console or VGA framebuffer on early machines, but nowadays that code is
> no longer used, except probably on the old footbridge/netwinder since
> that is the only one that supports vgacon.
>
> On machines with a framebuffer, booting with DT so far results in always
> using the hardcoded 80x30 size in dummycon, while on ATAGS the setting
> can come from a bootloader specific override. Both seem to be worse
> choices than the Kconfig setting, since the actual text size for fbcon
> also depends on the selected font.
>
> Make this work the same way as everywhere else and use the normal
> Kconfig setting, except for the footbridge with vgacon, which keeps
> using the traditional code. If vgacon is disabled, footbridge can
> also ignore the setting. This means the screen_info only has to be
> provided when either vgacon or EFI are enabled now.
>
> To limit the amount of surprises on Arm, change the Kconfig default
> to the previously used 80x30 setting instead of the usual 80x25.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Tested this before and after patch and it looks the same on the NetWinder.
Tested-by: Linus Walleij <linus.walleij@linaro.org>

The legacy in the cyber2000 FB driver supports pseudocolor which
makes it a bit hard to rewrite into a simple DRM driver, which is something
I could otherwise look into, it's not a very big or complex driver
after all.

Yours,
Linus Walleij