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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 94D90C433FE for ; Mon, 13 Sep 2021 16:55:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7911A61029 for ; Mon, 13 Sep 2021 16:55:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240747AbhIMQ5B (ORCPT ); Mon, 13 Sep 2021 12:57:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:46538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239888AbhIMQ47 (ORCPT ); Mon, 13 Sep 2021 12:56:59 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8A1CC60FE6; Mon, 13 Sep 2021 16:55:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631552143; bh=uUD9BeW8jFyLzVb0L7I3RCTD4qAQLcOLZZFlOvJ6GrQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OQ2w0/Elkm+1G3wLjr17l9B2+/QcO0UwFVduMARk/dIt2bTmoS2TlWAgP9Qxzhs/H J+HSjxT9vUVf8XG/e7ZSCTEmCXWQoPnwVdeAh1iAEWfp8EfomkJJy+4Usub5jDVxqt Z+8ktArEH3LiFcHHe9sNaMWlhtfg+cR9P4Xqv2TFxIjmrfBy8hWCPkQIOMJs+GutK0 IAkvz5z2Xn5xMOXmAhYKL5bn4N1fxu9fZB/UU7atC+NguZpIUdcSloYYkqDQybANSk +GethoLYKDThi70fW1qF2HrLi6pMB64PlYmRj5mcJIVrwnF6G8p3bK9JU0voZ/Ofhe xSEeZ2Sl0mYnw== Date: Mon, 13 Sep 2021 12:55:42 -0400 From: Sasha Levin To: Jean Delvare Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Heiner Kallweit , Wolfram Sang , linux-i2c@vger.kernel.org Subject: Re: [PATCH AUTOSEL 5.14 088/252] i2c: i801: Fix handling SMBHSTCNT_PEC_EN Message-ID: References: <20210909114106.141462-1-sashal@kernel.org> <20210909114106.141462-88-sashal@kernel.org> <20210909151320.7bddd134@endymion> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20210909151320.7bddd134@endymion> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 09, 2021 at 03:13:20PM +0200, Jean Delvare wrote: >Hi Sascha, > >On Thu, 9 Sep 2021 07:38:22 -0400, Sasha Levin wrote: >> From: Heiner Kallweit >> >> [ Upstream commit a6b8bb6a813a6621c75ceacd1fa604c0229e9624 ] >> >> Bit SMBHSTCNT_PEC_EN is used only if software calculates the CRC and >> uses register SMBPEC. This is not supported by the driver, it supports >> hw-calculation of CRC only (using bit SMBAUXSTS_CRCE). The chip spec >> states the following, therefore never set bit SMBHSTCNT_PEC_EN. >> >> Chapter SMBus CRC Generation and Checking >> If the AAC bit is set in the Auxiliary Control register, the PCH >> automatically calculates and drives CRC at the end of the transmitted >> packet for write cycles, and will check the CRC for read cycles. It will >> not transmit the contents of the PEC register for CRC. The PEC bit must >> not be set in the Host Control register. If this bit is set, unspecified >> behavior will result. >> >> This patch is based solely on the specification and compile-tested only, >> because I have no PEC-capable devices. >> >> Signed-off-by: Heiner Kallweit >> Tested-by: Jean Delvare >> Signed-off-by: Wolfram Sang >> Signed-off-by: Sasha Levin >> --- >> drivers/i2c/busses/i2c-i801.c | 27 +++++++++++---------------- >> 1 file changed, 11 insertions(+), 16 deletions(-) > >This patch fixes a theoretical problem nobody has ever complained >about. I don't think it makes sense to backport it to stable kernel >branches. Sure, I'll drop it. Thanks. -- Thanks, Sasha