Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754271AbbHFN7t (ORCPT ); Thu, 6 Aug 2015 09:59:49 -0400 Received: from www.linutronix.de ([62.245.132.108]:45924 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754207AbbHFN7r (ORCPT ); Thu, 6 Aug 2015 09:59:47 -0400 Message-ID: <55C36846.8010104@linutronix.de> Date: Thu, 06 Aug 2015 15:59:34 +0200 From: Sebastian Andrzej Siewior User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.7.0 MIME-Version: 1.0 To: Peter Hurley CC: John Ogness , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Tony Lindgren , linux-omap@vger.kernel.org, nsekhar@ti.com, nm@ti.com, linux-serial@vger.kernel.org, Heikki Krogerus Subject: Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown References: <87egjp2r4a.fsf@linutronix.de> <55BAC67E.1010400@hurleysoftware.com> <20150803160937.GA26497@linutronix.de> <55BF980E.20908@hurleysoftware.com> <55BF9CE0.4080107@linutronix.de> <55BFC1BA.5020605@hurleysoftware.com> <55C0A8F4.4010204@linutronix.de> <55C352A8.3070102@hurleysoftware.com> <55C3539F.4070403@linutronix.de> In-Reply-To: <55C3539F.4070403@linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1064 Lines: 29 On 08/06/2015 02:31 PM, Sebastian Andrzej Siewior wrote: Hi Peter, >> I'll look at/test this this weekend, ok? > > Sure. I'm currently re-spinning the patches so have everything in > proper pieces. While at it I will take a look at x_char. So now that I actually look at it. If I read this right, we never send the x_char if the TX-DMA never fails to do its job. The comment above uart_send_xchar() says it is high priority. What do you suggest, wait until the transfer completes, send the x_char _or_ pause the transfer send that byte and then send the byte? In both cases we have to wait until for the FIFO-empty interrupt to make sure we don't overrun that TX-FIFO. I *think* waiting until the transfer completes would be simpler but it is not necessarily high priority. >> Regards, >> Peter Hurley Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/