From owner-freebsd-current@FreeBSD.ORG Mon Dec 20 23:29:59 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1D0AA1065702; Mon, 20 Dec 2010 23:29:59 +0000 (UTC) (envelope-from delphij@delphij.net) Received: from tarsier.geekcn.org (tarsier.geekcn.org [IPv6:2001:470:a803::1]) by mx1.freebsd.org (Postfix) with ESMTP id BE8D78FC15; Mon, 20 Dec 2010 23:29:58 +0000 (UTC) Received: from mail.geekcn.org (tarsier.geekcn.org [211.166.10.233]) by tarsier.geekcn.org (Postfix) with ESMTP id DB50CA568CC; Tue, 21 Dec 2010 07:29:57 +0800 (CST) X-Virus-Scanned: amavisd-new at geekcn.org Received: from tarsier.geekcn.org ([211.166.10.233]) by mail.geekcn.org (mail.geekcn.org [211.166.10.233]) (amavisd-new, port 10024) with LMTP id VORWPyqdcuNI; Tue, 21 Dec 2010 07:29:50 +0800 (CST) Received: from delta.delphij.net (drawbridge.ixsystems.com [206.40.55.65]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by tarsier.geekcn.org (Postfix) with ESMTPSA id 8FBBFA56449; Tue, 21 Dec 2010 07:29:49 +0800 (CST) DomainKey-Signature: a=rsa-sha1; s=default; d=delphij.net; c=nofws; q=dns; h=message-id:date:from:reply-to:organization:user-agent: mime-version:to:cc:subject:references:in-reply-to: x-enigmail-version:openpgp:content-type:content-transfer-encoding; b=wxIc8z0+WEhxJgsE9REk4ynvO4JaeY6VeZNLUXNPIojburXekeH2U/2RL3u4CTKXe 5206leuY8Sn2nZXgD5sMg== Message-ID: <4D0FE6E9.1020609@delphij.net> Date: Mon, 20 Dec 2010 15:29:45 -0800 From: Xin LI Organization: The FreeBSD Project User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.1.16) Gecko/20101210 Thunderbird/3.0.11 ThunderBrowse/3.3.4 MIME-Version: 1.0 To: freebsd-current@freebsd.org References: <20101220231005.GA68477@freebsd.org> In-Reply-To: <20101220231005.GA68477@freebsd.org> X-Enigmail-Version: 1.0.1 OpenPGP: id=3FCA37C1; url=http://www.delphij.net/delphij.asc Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Alexander Motin Subject: Re: two ata write chaching request X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: d@delphij.net List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Dec 2010 23:29:59 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 12/20/10 15:10, Alexander Best wrote: > hi there, > > i'd really like to see > > 1) write caching to be turned on and off for individual hdds > (i.e. hw.ata.X.wc) and This is possible. We may need to split the logic out from ad_init() as the disk number is not known at that point if I understood the code correctly. > 2) to be able to turn write chaching on and off on the fly. If I understand the code correctly, this is merely issuing a SETFEATURE at runtime and *should* be possible. The problem is atacontrol(8) does not offer a way to issue the command directly as camcontrol(8) do. > any thoughts on these two topics? is it technically possible? > > cheers. > alex > - -- Xin LI http://www.delphij.net/ FreeBSD - The Power to Serve! Live free or die -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (FreeBSD) iQEcBAEBCAAGBQJND+bpAAoJEATO+BI/yjfBi3oH/RbzpLEDhDGj3cwvGZtNi6gx YuwWK77ybbJfm5OX1KAaBHMr954+8G9syiHzxamRwKSCsSooh9gdNL/ZUFFym9ay gsGDslkNINCOu19Cyd3F9SLiN+wym22siFJqakMf1yiZqrC7qxwOee42erwRnN9C +rbF25SWjNx+Y/BeCu+H9qwnzYZ719d2bNIA7DSgaOOcUUh+OQdKxt3JykEeUKpi mrEZ5NFxyuSDMkFenY0o1Zj3dH7y2s2o8Y3iJ/dxPWZHjL+Z/CZqMvNHu4eZzOa6 2XasZSgf1tvyGnkPJEbo+ClZny3wfKXm6lwChmtCz1wF1zv1sSCW/uqzjeBC0T8= =IOBO -----END PGP SIGNATURE-----