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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id E34EFCF9C6E for ; Mon, 23 Sep 2024 12:05:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=57Uz6MnU1j3xahihVP2lT+ameE3wU7kvWy7bwRKIGG4=; b=cFouEesVeCz+CIX3jIFlAUrezD vLS1Ll0aJ1hJ7r3mzGtaivPsWUkuV8t5F1+OIpaXacPRXIzNmJ9S7K2dT4h7C7TE8KLGD7Keslnuv 406OYZBAYb4LjINlDreVCrTOxZ7EA1+GdmSbXJNCDXq4rW9sn8Odttt0vyO631BzKAnqxsnMPjEPS qg6s3yKgw5xMVxnA/BLHyLdvsrG4loLMLjLa1vZB+OYVqdcc1EUSb7TlKOF+/VQ7Twi1PniLE4lmJ IHfY1sMTjEw44+kt4Mk8NrFeQQqYL6on95rm4HzgOe4HEF5AUedIKa2IZBtQp6U/42oZ+9k9t3zsJ 2lrjvbPg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1sshp0-0000000H8dT-3Y87; Mon, 23 Sep 2024 12:05:42 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1sshoy-0000000H8af-1ydV for linux-nvme@lists.infradead.org; Mon, 23 Sep 2024 12:05:42 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 2802068AFE; Mon, 23 Sep 2024 14:05:32 +0200 (CEST) Date: Mon, 23 Sep 2024 14:05:31 +0200 From: Christoph Hellwig To: Keith Busch Cc: Keith Busch , linux-nvme@lists.infradead.org, hch@lst.de, sagi@grimberg.me Subject: Re: [PATCH] nvme: remove CC register read-back during enabling Message-ID: <20240923120531.GB13481@lst.de> References: <20240904215405.1980512-1-kbusch@meta.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240923_050540_672412_1AE21605 X-CRM114-Status: GOOD ( 18.43 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Mon, Sep 23, 2024 at 10:03:32AM +0200, Keith Busch wrote: > On Wed, Sep 04, 2024 at 02:54:05PM -0700, Keith Busch wrote: > > From: Keith Busch > > > > Any non-posted read should flush the previous write, so we don't > > necessarily need to read back the value we just wrote. I've found at > > least some controllers that respond with 0 for short moments after > > writing the CC register with EN (enable) cleared, so the read-back is > > overwriting our valid ctrl_config value and ends up breaking on the > > subsequent enabling. > > Ping on this one. Looks okay? Looks good: Reviewed-by: Christoph Hellwig