From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 008.lax.mailroute.net (008.lax.mailroute.net [199.89.1.11]) (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 CD25C1DDD6; Tue, 14 May 2024 20:54:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.1.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715720063; cv=none; b=Zx88V7oiwzZoz9Onl/r9IdNAx2eaz0Ur2rSP+O57Y7iRmzQ8fvAeGz2veRwqtyVktJII7MbSXplAT0XOrvzq4iukM77JSTizrPY28zI0kPvdLy1XhuzM7eVIlv/rnaU0iHeUNTlb/Kso5VARI74DNhIy87BtrNFS7QNv2m4bfnY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715720063; c=relaxed/simple; bh=k9c4buxNu05Aufa9vu+21j4fvkSF4Yhlj0w7eGVwrtQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=G4j9nvC7Qx77WAfEIvHDV7awlU4CY0ceXkYhQoZG5N1i2g1+VjG6V1/s/GAYZ/FQxVj4rMI6evzUu8rwxFzdERxzuqg90KmsgFGRGwstaRFuyokUwsPERwWyev6ibzVMRlbIqEpvBkqzrpZe3Ny/13/cDC/piabRL9JEBpEv8Ro= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b=3OmKJQvT; arc=none smtp.client-ip=199.89.1.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b="3OmKJQvT" Received: from localhost (localhost [127.0.0.1]) by 008.lax.mailroute.net (Postfix) with ESMTP id 4Vf7rX6CxWz6Cnk90; Tue, 14 May 2024 20:54:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:content-type:content-type:in-reply-to :from:from:content-language:references:subject:subject :user-agent:mime-version:date:date:message-id:received:received; s=mr01; t=1715720058; x=1718312059; bh=IrNZfvETl7WV5WxVHxU5OxkN BAGTJ7bQra6C27GqQbQ=; b=3OmKJQvTWxx5XaT0ZKR+B39EHIuBkyUSELFQXCH3 MvbwbdjlwfQtwIVum7Rl/xVjBqg8rUdrl0FhafoxtND1l2yJTv1ql5ohTJm9g0Qb fhVfmRsGGYnErQpnBx7cHKa3o2GgW926ukb0ymdFgK2Ag4wLjd0T7fdWq869OxrJ GCXlj88K1bjARurv5/Sbvs244lBrvyOvBeYES4jBfSE73Q/b+c6ZSAzCKcRf2XUH YpFRNlw+1U8fS2xRZj1/YTgzJ4DYusFxbhMggw4un+XY1jYLWjv0fPuDZFLonigJ 1qkN5JhaR4+3YP0rhJsA27X08OdvpFyu+MrQJ1nZr6mB9A== X-Virus-Scanned: by MailRoute Received: from 008.lax.mailroute.net ([127.0.0.1]) by localhost (008.lax [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id cBeT42pl3TTG; Tue, 14 May 2024 20:54:18 +0000 (UTC) Received: from [172.21.16.125] (unknown [50.204.89.30]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 008.lax.mailroute.net (Postfix) with ESMTPSA id 4Vf7rT3lxnz6Cnk8s; Tue, 14 May 2024 20:54:17 +0000 (UTC) Message-ID: <0300cd4e-46d6-499a-98d5-72360c94ae49@acm.org> Date: Tue, 14 May 2024 14:54:14 -0600 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] scsi: ufs: Allow RTT negotiation To: Avri Altman , "Martin K . Petersen" Cc: Bean Huo , Peter Wang , "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20240514050823.735-1-avri.altman@wdc.com> <34c50f23-82dc-4b53-b8cb-e5c07c6e0106@acm.org> Content-Language: en-US From: Bart Van Assche In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/14/24 14:34, Avri Altman wrote: >> On 5/13/24 23:08, Avri Altman wrote: >>> +/* bMaxNumOfRTT is equal to two after device manufacturing */ >>> +#define DEFAULT_MAX_NUM_RTT 2 >>> [ ... ] >>> + /* do not override if it was already written */ >>> + if (dev_rtt != DEFAULT_MAX_NUM_RTT) >>> + return; >> >> I haven't found any text in the UFSHCI 4.0 specification that says >> that the default value for the number of outstanding RTT requests >> should be 2. Did I perhaps overlook something? If I didn't overlook >> anything, the driver should not try to check whether dev_rtt is at its >> default value. > JEDEC Standard No. 220F Page 150 Line 2837 says: "bMaxNumOfRTT is equal to two after device manufacturing," Thanks Avri for having looked this up. My understanding is that the above check won't work as intended if ufshcd_rtt_set() does not modify the RTT value. Wouldn't it be better to add a boolean in struct ufs_hba that indicates whether or not ufshcd_rtt_set() has been called before? Thanks, Bart.