From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Cox Subject: Re: [PATCH v2 1/4] tty: serial: Add 8250 earlycon to support noinit option Date: Mon, 12 Jan 2015 16:08:38 +0000 Message-ID: <1421078918.31978.32.camel@linux.intel.com> References: <1421068104-30463-1-git-send-email-eddie.huang@mediatek.com> <1421068104-30463-2-git-send-email-eddie.huang@mediatek.com> <3712986.8SuKNvhKTk@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3712986.8SuKNvhKTk@wuerfel> Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann Cc: linux-arm-kernel@lists.infradead.org, Eddie Huang , Rob Herring , Mark Rutland , Greg Kroah-Hartman , Matthias Brugger , devicetree@vger.kernel.org, Vladimir Murzin , srv_heupstream@mediatek.com, Pawel Moll , Ian Campbell , Catalin Marinas , Jonathan Corbet , Will Deacon , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, yh.chen@mediatek.com, Howard Chen , Ashwin Chaugule , linux-serial@vger.kernel.org, Kumar Gala , "Joe.C" , Jiri Slaby List-Id: linux-serial@vger.kernel.org On Mon, 2015-01-12 at 16:35 +0100, Arnd Bergmann wrote: > On Monday 12 January 2015 21:08:21 Eddie Huang wrote: > > Add earlycon support not only baudrate option, but also add noinit option. > > If use noinit option, 8250 earlycon will not init serial hardware and use > > loader setting. > > > > Signed-off-by: Eddie Huang > > I probably missed something in the previous discussion, but why is > "noinit" not just the default? I believe that is how we handle early > serial ports on PowerPC, and I see no downsides to it. Most PC hardware at least needs the port initialised to use it. It won't have been configured by the firmware in many cases. Alan From mboxrd@z Thu Jan 1 00:00:00 1970 From: alan@linux.intel.com (Alan Cox) Date: Mon, 12 Jan 2015 16:08:38 +0000 Subject: [PATCH v2 1/4] tty: serial: Add 8250 earlycon to support noinit option In-Reply-To: <3712986.8SuKNvhKTk@wuerfel> References: <1421068104-30463-1-git-send-email-eddie.huang@mediatek.com> <1421068104-30463-2-git-send-email-eddie.huang@mediatek.com> <3712986.8SuKNvhKTk@wuerfel> Message-ID: <1421078918.31978.32.camel@linux.intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 2015-01-12 at 16:35 +0100, Arnd Bergmann wrote: > On Monday 12 January 2015 21:08:21 Eddie Huang wrote: > > Add earlycon support not only baudrate option, but also add noinit option. > > If use noinit option, 8250 earlycon will not init serial hardware and use > > loader setting. > > > > Signed-off-by: Eddie Huang > > I probably missed something in the previous discussion, but why is > "noinit" not just the default? I believe that is how we handle early > serial ports on PowerPC, and I see no downsides to it. Most PC hardware at least needs the port initialised to use it. It won't have been configured by the firmware in many cases. Alan