From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74605C47404 for ; Mon, 7 Oct 2019 13:32:35 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 32E3E20867 for ; Mon, 7 Oct 2019 13:32:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="V9d3ZnuX"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="WTtQugSf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 32E3E20867 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=UAAyDdG6f6tHgBi4Wbl89ZuJodgyOsdMLbjNnyd/EVg=; b=V9d3ZnuXe/4KB1 nbNhaxgiqYYYRAXY1aC2E7+QWsksbjnuIqyZidi34Pe3LQP0/8PlYhiCBCN/pi/B707YXjjTKkCvf Hx1eKdEcGejSkWC596nsNZo0a1DfA+XqOi95PKvu/2pBuI/fxx64s8Q9NvaMtOdNoIAAt4Av/da8u YlNk2ccBZy0++ZGv4rxNL+ZsAtx2bfIVRSZoxcHwLqQf9UWVKirvgHuahXfSbXW/AQ35oFhMNXCL3 TvvpLnBMgzg0IyZm9b02XsV8RCDmleub4D+8a0Wvm7+DUwtBn1kGK4/rEFMNXlZh8ItbOU0gP6V25 3M0fKOeMNW4Fn0Adkl3g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iHT7o-0003EC-Kd; Mon, 07 Oct 2019 13:32:32 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iHT7l-0003Dp-R7 for linux-nvme@lists.infradead.org; Mon, 07 Oct 2019 13:32:31 +0000 Received: from C02WT3WMHTD6 (unknown [8.36.226.102]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 452E02064A; Mon, 7 Oct 2019 13:32:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570455149; bh=f6NOx7I3rz8/8d5/qtFLdVptLMgVUcd/WIGsVWWEtMg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WTtQugSfunXJNKtBXSTlDGK4KDtiOIE8AIqXbCz7zYdXfeFbYo2eWjfvZTtWeHV+s kNj9P4ItsyQormAfm1L/9bvTIzA9yXfCbZLOwvHDTRE5Srv0l4v7CopRAugUcl1nl7 gNdAEP/yfnsznC7Key8rjm0ZYwnUBzsSlbCid+Dc= Date: Mon, 7 Oct 2019 07:32:27 -0600 From: Keith Busch To: Ard Biesheuvel Subject: Re: [PATCH v3] nvme: retain split access workaround for capability reads Message-ID: <20191007133227.GA54763@C02WT3WMHTD6> References: <20191007114253.30735-1-ard.biesheuvel@linaro.org> <20191007120721.GA21060@lst.de> <20191007122738.GA24804@lst.de> <20191007124843.GA53339@C02WT3WMHTD6> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191007_063229_899893_D46D9D0F X-CRM114-Status: GOOD ( 11.74 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: axboe@fb.com, Ilias Apalodimas , Christoph Hellwig , linux-nvme@lists.infradead.org, sagi@grimberg.me Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Mon, Oct 07, 2019 at 03:20:11PM +0200, Ard Biesheuvel wrote: > On Mon, 7 Oct 2019 at 14:48, Keith Busch wrote: > > If you explain this patch by saying it's to fix a host controller, then the > > patch is no longer sufficient on it's own and should be fixed elsewhere, > > perhaps by providing a special pci_ops structure for your controller. > > Fair enough. Any suggestions for the wording of the comment? Something like this for the changelog: Subject: nvme/pci: Split 8-byte reads The nvme pci driver had split 8-byte register reads using lo_hi_readq() due to nvme controllers that do not support that sized access. This behavior was inadvertently changed to readq(), which may break those controllers. Restore the previous behavior. Fixes: 7fd8930f26be4 ("nvme: add a common helper to read Identify Controller data") And the comment: /* * Split the 8-byte read into two 4-byte reads since all controllers * support 4 byte register reads, but some do not support the larger * access size. */ _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme