Feedback-ID: i56a14606:Fastmail
User-Agent: Cyrus-JMAP/3.9.0-alpha0-85-gd6d859e0cf-fm-20230116.001-gd6d859e0
Mime-Version: 1.0
Message-Id: <6d1f3696-c94a-44ac-996c-83233f694cc0@app.fastmail.com>
In-Reply-To: <20230129160039.1598347-1-j.neuschaefer@gmx.net>
References: <20230129160039.1598347-1-j.neuschaefer@gmx.net>
Date:   Mon, 30 Jan 2023 09:08:10 +0100
From:   "Arnd Bergmann" <arnd@arndb.de>
To:     =?UTF-8?Q?Jonathan_Neusch=C3=A4fer?= <j.neuschaefer@gmx.net>,
        linux-arm-kernel@lists.infradead.org
Cc:     "Russell King" <linux@armlinux.org.uk>,
        "William Zhang" <william.zhang@broadcom.com>,
        "Michael Walle" <michael@walle.cc>,
        "Florian Fainelli" <f.fainelli@gmail.com>,
        "Tony Lindgren" <tony@atomide.com>,
        "Kavyasree Kotagiri" <kavyasree.kotagiri@microchip.com>,
        "Ard Biesheuvel" <ardb@kernel.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: Allow DEBUG_UNCOMPRESS on ARCH_MULTIPLATFORM
Content-Type: text/plain;charset=utf-8
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Sun, Jan 29, 2023, at 17:00, Jonathan Neusch=C3=A4fer wrote:
> A kernel with DEBUG_UNCOMPRESS=3Dy will only work on one platform, but
> that is already the case with DEBUG_LL=3Dy (and documented in its help
> text), and DEBUG_UNCOMPRESS depends on DEBUG_LL. Therefore, I don't
> think users need to be prevented from enabling DEBUG_UNCOMPRESS on
> ARCH_MULTIPLATFORM kernels.
>
> Signed-off-by: Jonathan Neusch=C3=A4fer <j.neuschaefer@gmx.net>

I think we should instead change the help text for CONFIG_DEBUG_LL.

There is a very significant difference between the requirements
of DEBUG_LL compared to DEBUG_UNCOMPRESS. The former only provides
the platform specific functions but does not call them unless
a user explicitly passes the "earlyprintk" command line argument
or adds explicit function calls to printascii(), while the latter
makes the kernel immediately unbootable.

     Arnd