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[86.9.19.6]) by smtp.gmail.com with ESMTPSA id u188sm14313631wmg.37.2020.05.04.07.40.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 May 2020 07:40:23 -0700 (PDT) Date: Mon, 4 May 2020 15:40:21 +0100 From: Daniel Thompson To: Douglas Anderson Cc: jason.wessel@windriver.com, gregkh@linuxfoundation.org, agross@kernel.org, kgdb-bugreport@lists.sourceforge.net, catalin.marinas@arm.com, linux-serial@vger.kernel.org, sumit.garg@linaro.org, corbet@lwn.net, mingo@redhat.com, will@kernel.org, hpa@zytor.com, tglx@linutronix.de, frowand.list@gmail.com, bp@alien8.de, bjorn.andersson@linaro.org, jslaby@suse.com, Andrew Morton , Juergen Gross , Mauro Carvalho Chehab , Pawan Gupta , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 08/11] Documentation: kgdboc: Document new kgdboc_earlycon parameter Message-ID: <20200504144021.kdr3zwvpqh2pj3cs@holly.lan> References: <20200428211351.85055-1-dianders@chromium.org> <20200428141218.v3.8.I7d5eb42c6180c831d47aef1af44d0b8be3fac559@changeid> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200428141218.v3.8.I7d5eb42c6180c831d47aef1af44d0b8be3fac559@changeid> Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Tue, Apr 28, 2020 at 02:13:48PM -0700, Douglas Anderson wrote: > The recent patch ("kgdboc: Add kgdboc_earlycon to support early kgdb > using boot consoles") adds a new kernel command line parameter. > Document it. > > Note that the patch adding the feature does some comparing/contrasting > of "kgdboc_earlycon" vs. the existing "ekgdboc". See that patch for > more details, but briefly "ekgdboc" can be used _instead_ of "kgdboc" > and just makes "kgdboc" do its normal initialization early (only works > if your tty driver is already ready). The new "kgdboc_earlycon" works > in combination with "kgdboc" and is backed by boot consoles. > > Signed-off-by: Douglas Anderson > Reviewed-by: Greg Kroah-Hartman > --- > > Changes in v3: > - Added example in kgdb.rst > - Removed unneeded sentence in kerenel-parameters doc. > - Renamed earlycon_kgdboc to kgdboc_earlycon. > - Suggest people use kgdboc_earlycon instead of ekgdboc. > > Changes in v2: None > > .../admin-guide/kernel-parameters.txt | 20 ++++++++++++++++ > Documentation/dev-tools/kgdb.rst | 24 +++++++++++++++++++ > 2 files changed, 44 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 7bc83f3d9bdf..3b5ae06a98aa 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1190,6 +1190,11 @@ > This is designed to be used in conjunction with > the boot argument: earlyprintk=vga > > + This parameter works in place of the kgdboc parameter > + but can only be used if the backing tty is available > + very early in the boot process. For early debugging > + via a serial port see kgdboc_earlycon instead. > + > edd= [EDD] > Format: {"off" | "on" | "skip[mbr]"} > > @@ -2105,6 +2110,21 @@ > kms, kbd format: kms,kbd > kms, kbd and serial format: kms,kbd,[,baud] > > + kgdboc_earlycon= [KGDB,HW] > + If the boot console provides the ability to read > + characters and can work in polling mode, you can use > + this parameter to tell kgdb to use it as a backend > + until the normal console is registered. Intended to > + be used together with the kgdboc parameter which > + specifies the normal console to transition to. > + > + The the name of the early console should be specified s/The the/The/ Other than that: Reviewed-by: Daniel Thompson