From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933806AbaFIXTE (ORCPT ); Mon, 9 Jun 2014 19:19:04 -0400 Received: from mail-vc0-f169.google.com ([209.85.220.169]:63724 "EHLO mail-vc0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751388AbaFIXTB (ORCPT ); Mon, 9 Jun 2014 19:19:01 -0400 MIME-Version: 1.0 In-Reply-To: References: <1397859600-11507-1-git-send-email-robherring2@gmail.com> <1397859600-11507-4-git-send-email-robherring2@gmail.com> <20140503220731.GA10927@kroah.com> <20140503221658.GA13403@kroah.com> Date: Mon, 9 Jun 2014 18:18:59 -0500 Message-ID: Subject: Re: [PATCH v2 3/7] tty/serial: convert 8250 to generic earlycon From: Rob Herring To: Tony Luck Cc: Greg Kroah-Hartman , Yinghai Lu , "linux-arm-kernel@lists.infradead.org" , Linux Kernel Mailing List , "linux-serial@vger.kernel.org" , Jiri Slaby , Catalin Marinas , Russell King , Will Deacon , Arnd Bergmann , Andrew Morton Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 9, 2014 at 5:35 PM, Tony Luck wrote: > On Mon, Jun 9, 2014 at 3:25 PM, Tony Luck wrote: >> Linus' tree (HEAD=963649d735c8) is spitting out all sorts of garbage >> on the serial console - as if the baud rate is being periodically set >> to something weird, and then back to 112500. I see over a dozen >> blocks of junk interspersed with good output. > > Ah - it seems that I need to be more specific on the cmdline > > console=uart8250,io,0x3f8,115200 > > makes all the garbage disappear. > > Do I need to update: Documentation/ia64/serial.txt > which has the example of "console=uart,io,0x3f8"? It should do auto detect of the baud-rate if it is not specified which for 8250 is just reading the baud-rate divider and calculating the baud-rate using the uart clock. It should just reprogram the divider with the same divider value. I don't see anything obvious why this would have broken. Rob From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v2 3/7] tty/serial: convert 8250 to generic earlycon Date: Mon, 9 Jun 2014 18:18:59 -0500 Message-ID: References: <1397859600-11507-1-git-send-email-robherring2@gmail.com> <1397859600-11507-4-git-send-email-robherring2@gmail.com> <20140503220731.GA10927@kroah.com> <20140503221658.GA13403@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-vc0-f169.google.com ([209.85.220.169]:63724 "EHLO mail-vc0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751388AbaFIXTB (ORCPT ); Mon, 9 Jun 2014 19:19:01 -0400 In-Reply-To: Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Tony Luck Cc: Greg Kroah-Hartman , Yinghai Lu , "linux-arm-kernel@lists.infradead.org" , Linux Kernel Mailing List , "linux-serial@vger.kernel.org" , Jiri Slaby , Catalin Marinas , Russell King , Will Deacon , Arnd Bergmann , Andrew Morton On Mon, Jun 9, 2014 at 5:35 PM, Tony Luck wrote: > On Mon, Jun 9, 2014 at 3:25 PM, Tony Luck wrote: >> Linus' tree (HEAD=963649d735c8) is spitting out all sorts of garbage >> on the serial console - as if the baud rate is being periodically set >> to something weird, and then back to 112500. I see over a dozen >> blocks of junk interspersed with good output. > > Ah - it seems that I need to be more specific on the cmdline > > console=uart8250,io,0x3f8,115200 > > makes all the garbage disappear. > > Do I need to update: Documentation/ia64/serial.txt > which has the example of "console=uart,io,0x3f8"? It should do auto detect of the baud-rate if it is not specified which for 8250 is just reading the baud-rate divider and calculating the baud-rate using the uart clock. It should just reprogram the divider with the same divider value. I don't see anything obvious why this would have broken. Rob From mboxrd@z Thu Jan 1 00:00:00 1970 From: robherring2@gmail.com (Rob Herring) Date: Mon, 9 Jun 2014 18:18:59 -0500 Subject: [PATCH v2 3/7] tty/serial: convert 8250 to generic earlycon In-Reply-To: References: <1397859600-11507-1-git-send-email-robherring2@gmail.com> <1397859600-11507-4-git-send-email-robherring2@gmail.com> <20140503220731.GA10927@kroah.com> <20140503221658.GA13403@kroah.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jun 9, 2014 at 5:35 PM, Tony Luck wrote: > On Mon, Jun 9, 2014 at 3:25 PM, Tony Luck wrote: >> Linus' tree (HEAD=963649d735c8) is spitting out all sorts of garbage >> on the serial console - as if the baud rate is being periodically set >> to something weird, and then back to 112500. I see over a dozen >> blocks of junk interspersed with good output. > > Ah - it seems that I need to be more specific on the cmdline > > console=uart8250,io,0x3f8,115200 > > makes all the garbage disappear. > > Do I need to update: Documentation/ia64/serial.txt > which has the example of "console=uart,io,0x3f8"? It should do auto detect of the baud-rate if it is not specified which for 8250 is just reading the baud-rate divider and calculating the baud-rate using the uart clock. It should just reprogram the divider with the same divider value. I don't see anything obvious why this would have broken. Rob