From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: Overriding/concatenating kernel command-line with bootargs from dtb? Date: Mon, 11 Jun 2012 19:51:30 +0200 Message-ID: <1424241.AIpjaKT9XL@bender> References: <2050174.dvvKJHKP0J@flexo> <4FD601F9.8020201@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FD601F9.8020201@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Rob Herring Cc: Benjamin Herrenschmidt , device-tree , linux-arm List-Id: devicetree@vger.kernel.org Hi Rob, On Monday 11 June 2012 09:34:33 Rob Herring wrote: > On 06/08/2012 02:55 AM, Florian Fainelli wrote: > > Hi all, > > > > I have a specific use case, where two boards using the same SoC have different > > UART speeds, which is something that I have specified in their corresponding > > dts files. In order to make sure people don't mess up the configuration, I > > prefer not to rely on the bootloader-supplied kernel-command line. > > > > I was kind of expecting that ARM_ATAG_DTB_COMPAT + CMDLINE_EXTEND would > > actually concatenate the kernel command-line with the bootargs provided from > > dtb. > > > > Is this something someone else would need? If so, shall we just make that > > happen when the two config symbols mentionned above are enabled, or shall we > > introduce a 4th kernel command line handling strategy? > > > > Thank you for your answers. > > There was a patch to do this: > > http://www.mail-archive.com/devicetree- discuss@lists.ozlabs.org/msg10448.html > > Please comment if this works for you. This patch indeeds work fine for me when I disable ARM_ATAG_DTB_COMPAT. If I let it turned on the chosen node is correctly scanned, but its value, is the one coming from tag_cmdline() which is actually the bootloader supplied commad-line. I will cook up a patch for this, because I expect the 3 command- lines to be concatened in the end (built-in, atag and dtb). I don't see any comments from Ben or anyone after Doug sent his version 2 of the patch, is there any reason not to merge it? -- Florian