From owner-cvs-src-old@FreeBSD.ORG Sat May 1 16:37:11 2010 Return-Path: Delivered-To: cvs-src-old@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 768E8106566B for ; Sat, 1 May 2010 16:37:11 +0000 (UTC) (envelope-from imp@FreeBSD.org) Received: from repoman.freebsd.org (repoman.freebsd.org [69.147.83.41]) by mx1.freebsd.org (Postfix) with ESMTP id 64A0F8FC13 for ; Sat, 1 May 2010 16:37:11 +0000 (UTC) Received: from repoman.freebsd.org (localhost [127.0.0.1]) by repoman.freebsd.org (8.14.3/8.14.3) with ESMTP id o41GbBSu037189 for ; Sat, 1 May 2010 16:37:11 GMT (envelope-from imp@repoman.freebsd.org) Received: (from svn2cvs@localhost) by repoman.freebsd.org (8.14.3/8.14.3/Submit) id o41GbBvt037188 for cvs-src-old@freebsd.org; Sat, 1 May 2010 16:37:11 GMT (envelope-from imp@repoman.freebsd.org) Message-Id: <201005011637.o41GbBvt037188@repoman.freebsd.org> X-Authentication-Warning: repoman.freebsd.org: svn2cvs set sender to imp@repoman.freebsd.org using -f From: Warner Losh Date: Sat, 1 May 2010 16:36:14 +0000 (UTC) To: cvs-src-old@freebsd.org X-FreeBSD-CVS-Branch: HEAD Subject: cvs commit: src/sys/conf NOTES options src/sys/dev/ath/ath_hal/ar5212 ar5212_reset.c X-BeenThere: cvs-src-old@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: **OBSOLETE** CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 01 May 2010 16:37:11 -0000 imp 2010-05-01 16:36:14 UTC FreeBSD src repository Modified files: sys/conf NOTES options sys/dev/ath/ath_hal/ar5212 ar5212_reset.c Log: SVN rev 207472 on 2010-05-01 16:36:14Z by imp The Atheros AR71xx CPUs, when paired with the AR5212 parts, has a bug that generates a fatal bus trap. Normally, the chips are setup to do 128 byte DMA bursts, but when on this CPU, they can only safely due 4-byte DMA bursts due to this bug. Details of the exact nature of the bug are sketchy, but some can be found at https://forum.openwrt.org/viewtopic.php?pid=70060 on pages 4, 5 and 6. There's a small performance penalty associated with this workaround, so it is only enabled when needed on the Atheros AR71xx platforms. Unfortunately, this condition is impossible to detect at runtime without MIPS specific ifdefs. Rather than cast an overly-broad net like Linux/OpenWRT dues (which enables this workaround all the time on MIPS32 platforms), we put this option in the kernel for just the affected machines. Sam didn't like this aspect of the patch when he reviewed it, and I'd love to hear sane proposals on how to fix it :) Reviewed by: sam@ Revision Changes Path 1.1582 +9 -0 src/sys/conf/NOTES 1.702 +1 -0 src/sys/conf/options 1.10 +8 -0 src/sys/dev/ath/ath_hal/ar5212/ar5212_reset.c