From: Sergei Shtylyov Subject: Re: [PATCH][MIPS][5/6]: AR7: serial hack Date: Tue, 18 Mar 2008 16:43:44 +0300 Message-ID: <47DFC710.5060907@ru.mvista.com> References: <200803120221.25044.technoboy85@gmail.com> <200803141646.09645.technoboy85@gmail.com> <20080315104009.GA6533@alpha.franken.de> <200803161645.06364.technoboy85@gmail.com> <20080318133015.GA7239@alpha.franken.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from h155.mvista.com ([63.81.120.155]:29284 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752514AbYCRNmZ (ORCPT ); Tue, 18 Mar 2008 09:42:25 -0400 In-Reply-To: <20080318133015.GA7239@alpha.franken.de> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Thomas Bogendoerfer Cc: Matteo Croce , linux-mips@linux-mips.org, Florian Fainelli , Felix Fietkau , Nicolas Thill , linux-serial@vger.kernel.org, Andrew Morton Hello. Thomas Bogendoerfer wrote: >>Il Saturday 15 March 2008 11:40:09 Thomas Bogendoerfer ha scritto: >>>On Fri, Mar 14, 2008 at 04:46:09PM +0100, Matteo Croce wrote: >>>>This is a bit better >>>is it possible to try without the serial changes first ? >>>Use >>> uart_port[0].type = PORT_16550A; >>>in arch/mips/ar7/platform.c. >>>Does it work ? >>Tried I get teh usual broken serial output: > I just checked the latest AR7/UR8 source, I have, and they don't need > special hacks. This is a 2.6.10 based tree. At that time there was > no serial8250_console_putchar(), console output was done via > serial8250_console_write() without any helper. Before writing to > the UART_TX, wait_for_xmitr() is called. And this wait_for_xmitr() does > check for BOTH_EMPTY. > Is there a good reason, why we don't check for BOTH_EMPTY in > serial8250_console_putchar() ? I guess transmission will be slower if you check both THRE and TSRE conditions. > To match the 2.6.10 behaviour we > would need that and this would fix the AR7 case without any > special handling. AR7 case seems to be the case of bad hardware, and so require special handling... > Thomas. WBR, Sergei