From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ew0-f224.google.com ([209.85.219.224]:62267 "EHLO mail-ew0-f224.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752352AbZERVVW (ORCPT ); Mon, 18 May 2009 17:21:22 -0400 Received: by ewy24 with SMTP id 24so4425975ewy.37 for ; Mon, 18 May 2009 14:21:23 -0700 (PDT) From: Max Filippov To: Kalle Valo Subject: Re: [PATCH 5/5] p54spi: use firmware/DMA bug workaround that work under hight load in p54spi_rx Date: Tue, 19 May 2009 01:21:13 +0400 Cc: linux-wireless@vger.kernel.org, Christian Lamparter References: <1242601355-3178-1-git-send-email-jcmvbkbc@gmail.com> <1242601355-3178-6-git-send-email-jcmvbkbc@gmail.com> <87tz3i9ram.fsf@litku.valot.fi> In-Reply-To: <87tz3i9ram.fsf@litku.valot.fi> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Message-Id: <200905190121.14103.jcmvbkbc@gmail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: > Max Filippov writes: > > Under high load first data word, read after available data size > > is sometimes lost in p54spi_rx. It seems to depend on frequency > > of interrupts and latency of data read request relatively to > > 'data available' interrupt. The worst consequence of this bug > > is loss of packet transmission acknowledgement, which in turn > > causes overflow of tx queues and permanent link loss. > > > > Read data size and first data word in one SPI transaction. > > No packets from LMAC should have length less than 1 word, > > so this shouldn't interfere with the next read transaction. > > There is a bug in omap2_mcspi which corrupts some DMA transfers, I don't > know if the bug you see is this one or something else. I'll send the > patch to linux-omap sometime later this week. I guess it will be easy to check whether your patch changes something in original p54spi behavior. I'll test this. Thanks. -- Max