From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754887Ab0INUFt (ORCPT ); Tue, 14 Sep 2010 16:05:49 -0400 Received: from tx2ehsobe003.messaging.microsoft.com ([65.55.88.13]:52268 "EHLO TX2EHSOBE005.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753722Ab0INUFs (ORCPT ); Tue, 14 Sep 2010 16:05:48 -0400 X-SpamScore: -15 X-BigFish: VS-15(zz1432N98dNef8Kzz1202hzzz2dh2a8h61h) X-Spam-TCS-SCL: 0:0 Date: Tue, 14 Sep 2010 15:05:39 -0500 From: Scott Wood To: Alan Cox CC: Andrew Morton , kumar.gala@freescale.com, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, amit.shah@redhat.com, Timur Tabi Subject: Re: [PATCH] hvc_console: fix dropping of characters when output byte channel is full Message-ID: <20100914150539.45c0672e@schlenkerla.am.freescale.net> In-Reply-To: <20100914204410.71942cdc@lxorguk.ukuu.org.uk> References: <1282329921-24394-1-git-send-email-timur@freescale.com> <20100914121721.c8671ed8.akpm@linux-foundation.org> <20100914204410.71942cdc@lxorguk.ukuu.org.uk> X-Mailer: Claws Mail 3.7.4 (GTK+ 2.20.1; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 14 Sep 2010 20:05:40.0538 (UTC) FILETIME=[348019A0:01CB5448] X-Reverse-DNS: az33egw01.freescale.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 14 Sep 2010 20:44:10 +0100 Alan Cox wrote: > > Yes, hvc_push() reschedules. It doesn't sit in a tight loop burning > > electrons! > > > > Can we do something safer&smarter here? > > > Its a printk handler - better to lose the bytes than hang the box. I > think the current code is probably right. Losing the bytes is unacceptable. Even if an hvc backend erroneously returns zero on a permanent error, the timeout should prevent hanging the box for too long. Though I suspect the right answer for us may be "don't use the hvc layer". -Scott