From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 003.mia.mailroute.net (003.mia.mailroute.net [199.89.3.6]) (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 8956F2E7658; Tue, 7 Oct 2025 16:20:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.3.6 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759854006; cv=none; b=kNxvT6wdfeHlDXNXnVfjnL9h+VZUvymu5p6bC2s1KRetj7vPzNSRBp8UP06SN1/cz8gdv7Aw8wLzhF7rSRmja1VHJfICljTgo9e4ogqfTyA9uNuofKQCYg1NevlkXrU/GVAylFbDwnpvO1SiUNSV/SNsr3nHlHKkzwmkJiym39E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759854006; c=relaxed/simple; bh=h/Eg/Uc6BoL1pnkILtNEBcDhyDg10QbRxuCgWt+axpY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lcTtT0/qbLnn7CGv/dTmOC+QuFihGwCyykR/27Qgr2v8h9uu+PpkHM0rcFzyuS3TqnZbqDm6PU4NyA5ldCMJjxI9xlLKM/FSVwbThE7kxZ8dAi+m2pLaaiWUUsBP564wIYfTuSSMOFM4XIc/gHAnIPxRs4oVfxExfYTidQo3QaE= 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=xoD0pR9R; arc=none smtp.client-ip=199.89.3.6 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="xoD0pR9R" Received: from localhost (localhost [127.0.0.1]) by 003.mia.mailroute.net (Postfix) with ESMTP id 4ch1ZC2hjJzlgqV0; Tue, 7 Oct 2025 16:20:03 +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=1759854000; x=1762446001; bh=h/Eg/Uc6BoL1pnkILtNEBcDh yDg10QbRxuCgWt+axpY=; b=xoD0pR9RDOxtIlxFtnRIjLF5rDcQM0X1iuuILYui O3QZUQDkXGb+c8M22sxgLJJEt/jyua8CnJfK1FlY7ovl1bTcwuSpuZJutVBviAEk txlm9ekn8MOKdM0iDBnrUH9VMVBpQW/S6SV7nJYSS27TYQg65+MkPS8F5oRTenjA l/09DjusndKDTO86kC6vhfpzfvG0oMyOeoVfA6Yy5rW4j0RFuYbFKJ0Gy+j54Xgm CclaftVCQ6yBhavTdG6erMsRG/mDOscI97eVXrsU/GL/pP1t+AtXCFb2+1mRnJLc UnaHZ+eowxsGQXuJkPVKDQIkJPrI3c+ICHVi+PLxaKEcLg== X-Virus-Scanned: by MailRoute Received: from 003.mia.mailroute.net ([127.0.0.1]) by localhost (003.mia [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id sWalvk3kUJVJ; Tue, 7 Oct 2025 16:20:00 +0000 (UTC) Received: from [100.119.48.131] (unknown [104.135.180.219]) (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 003.mia.mailroute.net (Postfix) with ESMTPSA id 4ch1Yt1s7vzlgqVF; Tue, 7 Oct 2025 16:19:45 +0000 (UTC) Message-ID: <2ce08f9f-af8c-4cac-8d66-97517eb18037@acm.org> Date: Tue, 7 Oct 2025 09:19:44 -0700 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 v1 2/2] scsi: ufs: core: Reduce the sleep before vcc can be powered on To: =?UTF-8?B?UGV0ZXIgV2FuZyAo546L5L+h5Y+LKQ==?= , "avri.altman@wdc.com" , "quic_cang@quicinc.com" , "quic_nitirawa@quicinc.com" , "quic_nguyenb@quicinc.com" , "manivannan.sadhasivam@linaro.org" , "adrian.hunter@intel.com" , "martin.petersen@oracle.com" Cc: "linux-scsi@vger.kernel.org" , "beanhuo@micron.com" , "alim.akhtar@samsung.com" , "James.Bottomley@HansenPartnership.com" , "linux-kernel@vger.kernel.org" References: <4943d9d6e31b2993ee0563722b8bc38c3b1ef069.camel@mediatek.com> <234a5185-d7f3-fe81-9c02-7895691c1fbd@quicinc.com> <85bce5dc28293f48e32b64eed5591d66c54c9e69.camel@mediatek.com> Content-Language: en-US From: Bart Van Assche In-Reply-To: <85bce5dc28293f48e32b64eed5591d66c54c9e69.camel@mediatek.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable On 10/7/25 12:04 AM, Peter Wang (=E7=8E=8B=E4=BF=A1=E5=8F=8B) wrote: > On Fri, 2025-10-03 at 14:27 -0700, Bao D. Nguyen wrote: >> With the current or recent offerings of ufs devices in the market,=20 >> the requirement is 1ms. For example, the Kioxia datasheet says >> "Vcc shall be kept less than 0.3V for at least 1ms before it goes >> beyond 0.3V again". Similarly other vendors have this 1ms >> requirement. So I believe this indicates the worst case scenario.=20 >> I understand there may be very old devices that are upgrading the=20 >> kernel only. In that case I don't know the specifics for these old >> ufs parts as mentioned. >=20 > Hi Bao, >=20 > Please consider using module_param_cb to set the default > delay to 2ms(or 1ms). At the same time, we should keep the > flexibility for devices that may require a longer delay by > allowing them to extend the delay through a module parameter. Why a kernel module parameter? Why can't the default delay be set by ufshcd_variant_ops.init()? Thanks, Bart.