Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751665AbWHTGck (ORCPT ); Sun, 20 Aug 2006 02:32:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751661AbWHTGck (ORCPT ); Sun, 20 Aug 2006 02:32:40 -0400 Received: from gate.crashing.org ([63.228.1.57]:9352 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S1750759AbWHTGcj (ORCPT ); Sun, 20 Aug 2006 02:32:39 -0400 Subject: Re: [PATCH 2/6]: powerpc/cell spidernet low watermark patch. From: Benjamin Herrenschmidt To: Arnd Bergmann Cc: linuxppc-dev@ozlabs.org, akpm@osdl.org, James K Lewis , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Jeff Garzik , ens Osterkamp In-Reply-To: <200608190109.15129.arnd@arndb.de> References: <20060818220700.GG26889@austin.ibm.com> <20060818222146.GI26889@austin.ibm.com> <200608190109.15129.arnd@arndb.de> Content-Type: text/plain Date: Sun, 20 Aug 2006 16:31:49 +1000 Message-Id: <1156055509.5803.77.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 657 Lines: 20 > card->low_watermark->next->dmac_cmd_status |= SPIDER_NET_DESCR_TXDESFLG; > mb(); > card->low_watermark->dmac_cmd_status &= ~SPIDER_NET_DESCR_TXDESFLG; > card->low_watermark = card->low_watermark->next; > > when we queue another frame for TX. I would have expected those to be racy vs. the hardware... what if the hardware is updating dmac_cmd_status just as your are trying to and the bit out of it ? Ben - 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/