Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262508AbVEMTU3 (ORCPT ); Fri, 13 May 2005 15:20:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262507AbVEMTSB (ORCPT ); Fri, 13 May 2005 15:18:01 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:1256 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S262487AbVEMTO5 (ORCPT ); Fri, 13 May 2005 15:14:57 -0400 Subject: Re: tickle nmi watchdog whilst doing serial writes. From: Arjan van de Ven To: Dave Jones Cc: akpm@osdl.org, linux-kernel@vger.kernel.org In-Reply-To: <20050513184806.GA24166@redhat.com> References: <20050513184806.GA24166@redhat.com> Content-Type: text/plain Date: Fri, 13 May 2005 21:14:52 +0200 Message-Id: <1116011692.6694.19.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 (2.0.4-4) Content-Transfer-Encoding: 7bit X-Spam-Score: 3.7 (+++) X-Spam-Report: SpamAssassin version 2.63 on pentafluge.infradead.org summary: Content analysis details: (3.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 1.1 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [] 2.5 RCVD_IN_DYNABLOCK RBL: Sent directly from dynamic IP address [80.57.133.107 listed in dnsbl.sorbs.net] 0.1 RCVD_IN_SORBS RBL: SORBS: sender is listed in SORBS [80.57.133.107 listed in dnsbl.sorbs.net] X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 925 Lines: 28 On Fri, 2005-05-13 at 14:48 -0400, Dave Jones wrote: > if (up->port.flags & UPF_CONS_FLOW) { > tmout = 1000000; > while (--tmout && > - ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0)) > + ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0)) { > udelay(1); > + touch_nmi_watchdog(); > + } > } > } > > > We *could* tickle it less often, but given we're busy waiting anyway > it probably doesnt make sense to not favour the more simple approach. > Hmm, maybe we want a cpu_relax() in there too. opinions? udelay() includes cpu_relax() already so that is futile. However.. this is a hack. Do we really need to do busy waiting here for this long?? - 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/