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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB623C43381 for ; Fri, 8 Mar 2019 14:52:17 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9C19D2087C for ; Fri, 8 Mar 2019 14:52:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="IVCM+cqn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9C19D2087C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=the-dreams.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject: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=DepuicbXm8FUgV7y2yDfx6OEWaVSt1wNoKBVl8lQ9zQ=; b=IVCM+cqnwsW8QisDlz2EEegnz pxVRp+49uU51NZQMufd/OReS9PXEtqL2iKif3SZRaXR2zpbczCUHDxs//q5qVqxOQxIURrkFAztU6 MEiLzpefaHQ9LYPe7dN3QUcHtaBuFmp14mvM1SrsIWXj0vAVj4NUsGC+qNTmX3CHcTfl/1fFTjEaI Ln/fMOzF64R1zAGvjkzsk01b5jpO25cHLsYrOS58RnKQMKhozOQGCnV+fiFdHAVHc7xeg2MeI2jF0 L/86cxz8RPq6NtPb3zjTYA1BJHV5qWCwjHaH0K9u8eqda86o7YOQ1RM1j4xv373+wTthg5HZ7dTUn KOXqkS+xQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h2Gr4-0003C1-S6; Fri, 08 Mar 2019 14:52:10 +0000 Received: from sauhun.de ([88.99.104.3] helo=pokefinder.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h2Gqz-0003BH-Sw; Fri, 08 Mar 2019 14:52:09 +0000 Received: from localhost (p54B3343A.dip0.t-ipconnect.de [84.179.52.58]) by pokefinder.org (Postfix) with ESMTPSA id D16B02C3F83; Fri, 8 Mar 2019 15:52:03 +0100 (CET) Date: Fri, 8 Mar 2019 15:52:03 +0100 From: Wolfram Sang To: Hsin-Yi Wang Subject: Re: [PATCH] i2c: mediatek: modify threshold passed to i2c_get_dma_safe_msg_buf() Message-ID: <20190308145203.GA4743@kunai> References: <20190215090202.157100-1-hsinyi@chromium.org> <20190215090959.soxkf3ho3or2geme@ninjato> <20190215092500.6q3hqnoufyowiqaz@ninjato> <20190215163657.fs6t7p3vqez53su3@ninjato> <20190308112919.GA1674@kunai> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190308_065207_747619_B6F428A9 X-CRM114-Status: UNSURE ( 8.38 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ryder Lee , qii.wang@mediatek.com, Jun Gao , linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-i2c@vger.kernel.org, Matthias Brugger , linux-arm-kernel@lists.infradead.org Content-Type: multipart/mixed; boundary="===============0047912033032761910==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============0047912033032761910== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="mP3DRpeJDSE+ciuQ" Content-Disposition: inline --mP3DRpeJDSE+ciuQ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline > > I just checked this issue again and concluded that both are reasonable, > > the suggestion from me below with the adapter quirk AND your original > > patch setting the threshold to 1. With my suggestion the core will > > prevent 0-length messages. But still, we should set the threshold to 1 > > because 0 is a value the HW is not capable of. > > > I think quirk might be better, since mediatek said they might have some ICs > that can handle zero-length transfer in the future, so flags might be > more clear if they want to restore functionality. But I guess you don't want to do the zero-length transfer with DMA then? With that in mind, raising the threshold still makes sense to me. --mP3DRpeJDSE+ciuQ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAlyCgY8ACgkQFA3kzBSg KbZ2Qg/9GaOmyLxHs9ayEmGtGSYNxgpXmj+fMfBqvL2OlsSPG8EDNtIs5n7+p7Lq gPz2Tm0EnnCkIWmpp4EFhON17ZkuIVthAO7lMTacqk6lAxMqP2d5qtbtTllHerdZ 2whXvhfxEOobWGDQoxstTv/mgSLckRaltjteITi17UqFdRAQsIJOerJ+MY9QOFrt xi+bDnwiV8YEsgRX9iWSUx3kKPel+n36oiAY+5/ONHE1+R5KOmdGHpRPHTzhB99Q sn8XZe2hGPKNbF/j3RdDOmO6Qbd5jlWEg7IlHnqJx1Bbi2rJfEqPG/Z6kcI+lE8l gUPlYlS2VMLZ7D6td11AVgBAThDjlguVzzVr0vf/kKBXRojRf3rNd6AQDg46TSE4 5k73pVpD2G1mnlbryQKG2tQOw1XB8CCIfgRQA1AquCoUdwrPZAdTYD9V7qdqkW7y 9OWwM/bmkEZHpnpUZNxxGBKuGoTIOOmhAIgjMpKw1/z2iIm3cZM/T/J9wRCH70Jr 1cRwRSUgz2SgrqZ2SjGC/arXgyhUCv6Xtn1XXRRr+dnhOVQGynfls0ooNcLO6O9V TlrASHvc5wmXTtYr3QIeytDqwmbZmj7H8LtItRlTAz2XH7zTkfDHEijW9HAMJ0zu 3k4PWLCIwV93n3127uNNwXGpUTHlhgxWlIwVR1WsLOsreLblXZY= =7FL8 -----END PGP SIGNATURE----- --mP3DRpeJDSE+ciuQ-- --===============0047912033032761910== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============0047912033032761910==--