From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=213.95.11.211 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794517644; b=1l48npv1u8PxHkSJDqBrIpvfPpLoMh+VcekJoTv0UqGdNW7VTpVKq5d3gdu6s5S5zOVd BeJou8lcy90riCd9zH+5V+LN8G4yBj2uAsy1eB7yAeWVrJnTnV5n5hc9YEXNqHgxH5SWt qDhgSH0sg2kr6uzS67yPyy80lB6u3qz8A/7SCDwqlzGAoCTNSWvXrtk8kK16jcLjFDYbX DN4u3cMbwu4Kjyr7r/QgaBFAG58KGvaatJk1sfKLps4IKomOMOH157VifovgD2/J41C/G b8yvQWt9XgrweYTttNO7eYZIBkAtjedBnMqom5Ssz0oWz+qYhydnMc8VcpboMZ0tnYw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794517644; h=DMARC-Filter:Received:Date:From:To:Cc:Subject:Message-ID:References: MIME-Version:Content-Type:Content-Disposition:In-Reply-To:User-Agent; bh=KPcGxWktlaGg63UoR245IUkJTtv/C1wkP9UzgLCl4Ro=; b=XrI8yEF2xYvnNYSd/aAR4y5qWndOT2/9RYpSfjALkAyCTTXOTT16wsx6IXiS9wdUVAeD ZsRBBfyqHFHeiKpyleY9SKTiJFqont1eYSDtRrm29rG6u2mBW/mMhcTFjkoXeXs+wi/dW hk5Bas+o2mn8fcVvXHd983JIrJhrqQ9z9J/aErmsENN5qPtrhNZKtS1p8te7S/imGpdjy 6mqV/kkJUzo4P3JD7jFM3uTrhd1KbB9LioA8USyEM01ga81v8dBIR1C1Ja4rkU1vozh7e Cym0eh3OASjYaaLjMbCd7QvNIvGjvQxRjO66b3nclrVI5LnTFmWrxAhC5PFXSZgJ0ZA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.remote-ip=213.95.11.211 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BAFCB606A31C; Thu, 12 Nov 2026 21:07:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org BAFCB606A31C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 12F196732A; Thu, 12 Nov 2026 22:07:19 +0100 (CET) Date: Thu, 12 Nov 2026 22:07:18 +0100 From: Christoph Hellwig To: Paul Menzel Cc: Bjorn Helgaas , dlemoal@kernel.org, cassel@kernel.org, kbusch@kernel.org, axboe@kernel.dk, hch@lst.de, sagi@grimberg.me, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Alexey.Bogoslavsky@sandisk.com Subject: Re: [PATCH RFC] PCI: Start the reset of WD PC SN730 NVMe controllers early Message-ID: <20261112210718.GA11040@lst.de> References: <20261111163145.75027-2-pmenzel@molgen.mpg.de> X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261111163145.75027-2-pmenzel@molgen.mpg.de> User-Agent: Mutt/1.5.17 (2007-11-01) On Wed, Nov 11, 2026 at 05:31:43PM +0100, Paul Menzel wrote: > devmem, works: the driver finds CSTS.RDY clear and continues, the reset > completed within the first poll in 29 of 30 boots (35 polls once), and > none of the 30 boots showed a slow reset, enable or read, against 8 of > 90 without it. The difference is not yet significant (p = 0.1). > > So start the reset in a final fixup during enumeration, at 0.19 s on > this machine, about 100 ms before nvme probes, which overlaps a slow > reset with the remaining kernel initialization and the module loading, > and costs nothing for fast ones. Umm, no. PCI quirks are not a way to speed up slow device initialization, which while annoying is not a bug per se.