From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id A41E11A002B for ; Fri, 12 Feb 2016 15:44:05 +1100 (AEDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 6678C1402C4; Fri, 12 Feb 2016 15:44:05 +1100 (AEDT) Subject: Re: [PATCH 1/2 v2] serial/aspeed-vuart: Only disable host tx discard when serial port is in use To: Stewart Smith , openbmc@lists.ozlabs.org References: <1455179165-13252-1-git-send-email-jk@ozlabs.org> <1455179366-13956-1-git-send-email-jk@ozlabs.org> <87bn7mophf.fsf@linux.vnet.ibm.com> From: Jeremy Kerr X-Enigmail-Draft-Status: N1110 Message-ID: <56BD6314.8010609@ozlabs.org> Date: Fri, 12 Feb 2016 12:44:04 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <87bn7mophf.fsf@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Feb 2016 04:44:05 -0000 Hi Stewart, >> OpenPOWER firmware doesn't like it when the host-side of the VUART's >> FIFO is not drained. This change only disables host TX discard mode when >> the port has been opened. > > Do we have what's arguably a bug somewhere? I'm not 100% sure that it's a bug; it's fairly reasonable to expect that a UART's TX FIFO will be drained. That expectation is present in a lot of different UART implementations (including skiboot & Linux). Cheers, Jeremy