From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 06592535C8 for ; Thu, 6 Jun 2024 23:08:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717715326; cv=none; b=lwaxK+o+ROT4cvYKSrgrtqyBtLNN1O+0hQlq1EftahIkeNcdEeLoyv5EaiT4HWLR7JivI6f+N/wqJNxUyuqbV9Hqbf+2WI8pqRaySO/tiFKwxFYVvF+mx5Zc9g3BxV5ZdDfNC9F/+qow9GBsGFINTbZzZ6df2QzgsC3KxYQdwxQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717715326; c=relaxed/simple; bh=ivHRm8Gc/TIPEtghMOHVC9hUSg8uXYUJQq6cqKdRRG4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WNDGir++jh296iTe0lqFmA1KZ1Yr//awRSQ5NmdhNYFbWsw+PN7kWo2+U8KWRWRBu3Ra2HVtHuxxGZ3dPu63AqBKdbgA5vhZQsx5VB6gkN780Xbs6EGYKSEEPFIJGF5nG/eHnePqxNvynQRDevNVTlCOXO5DXZ9DbjZnOpypRQ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bNcEs2PL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bNcEs2PL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE4DDC2BD10; Thu, 6 Jun 2024 23:08:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717715325; bh=ivHRm8Gc/TIPEtghMOHVC9hUSg8uXYUJQq6cqKdRRG4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=bNcEs2PLB+CcrUbVUtMKnvgMD6Ox3GRmW2V9oarfBqYixCiQduX7/N1rqBZcpmEhs ToivSK8yJ2aQbn793s3qcKSnxM4mtT7Hr0ItDrHVbQoODGO1/LcErCmEGLqnAhaVV9 sMQiuRECsqWQrTscMQVq8z0SVtW/p30+nL+yhHcTs73ZCnbNJ28DNW23UklKI6uoF/ Me/Syo2SjZyoaFuW4mEKfutMkbmqOm2w9JNl8eX757w0MPUtJz1z4wSFqtO8K5BQWQ kQhDjRsPDN7TfP/tUg9B9hcA+rCiraotPewb2tV4w8Jjhhsu4fv2BmxGxrVCeZtYww B6sICjLtiupFw== Message-ID: <7e27dc26-ab23-465f-8cd2-97e635fc37b3@kernel.org> Date: Fri, 7 Jun 2024 08:08:43 +0900 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] scsi: core: Disabe CDL by default To: Bart Van Assche , "Martin K . Petersen" , linux-scsi@vger.kernel.org, Christoph Hellwig Cc: Niklas Cassel References: <20240606054606.55624-1-dlemoal@kernel.org> <03766042-bfa8-44bf-9684-44a912ad2c73@acm.org> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <03766042-bfa8-44bf-9684-44a912ad2c73@acm.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/7/24 00:48, Bart Van Assche wrote: > On 6/5/24 23:46, Damien Le Moal wrote: >> For scsi devices supporting the Command Duration Limits feature set, the >> user can enable/disable this feature use through the sysfs device >> attribute cdl_enable. This attribute modification triggers a call to >> scsi_cdl_enable() to enable and disable the feature for ATA devices and >> set the scsi device cdl_enable to the user provided bool value. > > Do we really need to disable CDL by default? Has it been considered to > enable CDL by default if the Command Duration Limit mode pages that have > been defined in SPC-5 are supported? We cannot do that as that would potentially break users of ATA NCQ priority. The reason is that for ATA drives that support both NCQ priority and CDL, if CDL is enabled, NCQ priority cannot be used. If we were to change CDL to be enabled by default, NCQ priority users would need to disable it before enabling NCQ priority. That can break existing setups. And this has been like this since kernel 6.5, so I am not going to change this now. -- Damien Le Moal Western Digital Research