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=-4.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, FSL_HELO_FAKE,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 A872CC433E2 for ; Mon, 31 Aug 2020 15:01:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F909207EA for ; Mon, 31 Aug 2020 15:01:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="vCSU+xwU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728064AbgHaPBo (ORCPT ); Mon, 31 Aug 2020 11:01:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50780 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726144AbgHaPBm (ORCPT ); Mon, 31 Aug 2020 11:01:42 -0400 Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38912C061573 for ; Mon, 31 Aug 2020 08:01:42 -0700 (PDT) Received: by mail-pl1-x641.google.com with SMTP id l9so1517132plt.8 for ; Mon, 31 Aug 2020 08:01:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=h7lNOgEVyx8v8t9yCT4l2hOs5HP15stuEYfKGUuqjcw=; b=vCSU+xwUziyBzy6HJMzdg00tJREFrP2dkQdl5taF7mkM777FmeuBl8dHZGclQSQHxn rsjgmTOI4KylSj/vPvvpq7STma9cICZTPfBln4Fy8SRwMQNQHxPvYQ5wT2wVM67HnzgV 73dP5IXso1heziZQr69iCB8Ab41moQtiioQGyXBk0Y/Pk7HKeXf57EzjyVYiBQZAAQ7w ZhNB+5deI2IW+gJPr1/RWkau0lEOpn2c1DFAqqx685phrNfk4MkoewpzdHw/69B4P1cZ QRZSO/D1UmpTpDTdclXkOlt9cb/a1ANx1eheAaX80rMa4l+sUY8FqTQA1cUbOPeYeeGn fofQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=h7lNOgEVyx8v8t9yCT4l2hOs5HP15stuEYfKGUuqjcw=; b=gwK1+6YAf5DTVbcwZBcTtu3YYlNbRM32vBFxu7w8Yh/B5KF6ylGBOlRq4nRwkHY24d 2aFGcVznjvznprcG+9PbrHGa/N+rCbpys8XhcEB4UqtbS9fL2Bi1BsfoNMdAh494qlDo 0E7bpVLYoF0WZ9kMc2cGU/QfAdRJCPbtAfryhXeyNVxPL7+a0P188rirAQuyDfWYnuhG BFT9u2A0Vp+aeMgL37yJKgKMQkWhpPgGIB6HAVJvXPeMZAzW8b7jte0FAl+gkH21zt3t BY4adMxfnsXFc2SCnN0uC/CGgLOabNTSM24qBZ94Ik4j9jOYpeiIv5mikdu9+4aW0Bsr E+pg== X-Gm-Message-State: AOAM532gHdjNLgvjVv7ppfiA929cdArVRxEjdipq6i5CIcpZBIgCt1Wi 5cNnYd1nfQQtjinJRIVxhGU= X-Google-Smtp-Source: ABdhPJyEuTj/YsQ9iFYL40AtFocRJO+8YqBnZhDo22dPGjCLvLh+UJ9acxVdvVfaWhIDVH0VQKiWkA== X-Received: by 2002:a17:902:780f:: with SMTP id p15mr1393163pll.56.1598886101587; Mon, 31 Aug 2020 08:01:41 -0700 (PDT) Received: from gmail.com ([223.190.108.199]) by smtp.gmail.com with ESMTPSA id 67sm606092pfv.173.2020.08.31.08.01.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 31 Aug 2020 08:01:40 -0700 (PDT) Date: Mon, 31 Aug 2020 20:29:29 +0530 From: Vaibhav Gupta To: Wolfram Sang Cc: Jean Delvare , Linux I2C , Volker =?utf-8?Q?R=C3=BCmelin?= , Bjorn Helgaas , Vaibhav Gupta Subject: Re: [PATCH] i2c: i801: Fix resume bug Message-ID: <20200831145929.GA11480@gmail.com> References: <20200825191303.4a258073@endymion> <20200828085753.GH1343@ninjato> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200828085753.GH1343@ninjato> Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On Fri, Aug 28, 2020 at 10:57:53AM +0200, Wolfram Sang wrote: > On Tue, Aug 25, 2020 at 07:13:03PM +0200, Jean Delvare wrote: > > From: Volker Rümelin > > > > On suspend the original host configuration gets restored. The > > resume routine has to undo this, otherwise the SMBus master > > may be left in disabled state or in i2c mode. > > > > [JD: Rebased on v5.8, simplified a condition.] > > > > Signed-off-by: Volker Rümelin > > Signed-off-by: Jean Delvare > > --- > > I noticed this bug in a QEMU x86_64 q35 VM booted with OVMF. OVMF > > doesn't initialize the SMBus master. After 1s of SMBus inactivity > > autosuspend disables the SMBus master. To reproduce please note QEMU's > > ICH9 SMBus emulation does not handle interrupts and it's necessary > > to pass the parameter disable_features=0x10 to the i2c_i801 driver. > > > > Note from JD: I can't test this. > > Thanks for keeping up with this one. I have one high level comment but I > hope Volker, Bjorn, and Vaibhav have comments/tags, too. > > > +static unsigned char i801_setup_hstcfg(unsigned char hstcfg) > > +{ > > + hstcfg &= ~SMBHSTCFG_I2C_EN; /* SMBus timing */ > > + hstcfg |= SMBHSTCFG_HST_EN; > > + return hstcfg; > > +} > > What about putting the write to SMBHSTCFG here, too. When I read the > function name, I assumed it will do that. > > > @@ -1961,8 +1965,11 @@ static int i801_suspend(struct device *d > > > > static int i801_resume(struct device *dev) > > { > > - struct i801_priv *priv = dev_get_drvdata(dev); > > + struct pci_dev *pci_dev = to_pci_dev(dev); > > + struct i801_priv *priv = pci_get_drvdata(pci_dev); > > + unsigned char hstcfg = i801_setup_hstcfg(priv->original_hstcfg); > > > > + pci_write_config_byte(pci_dev, SMBHSTCFG, hstcfg); > > And on top of that, we could skip the 'hstcfg' variable here. > Add extra parameter of "struct pci_dev*" type in i801_setup_hstcfg(). We can also skip the introduction of "struct pci_dev*" type variable in .resume() then. Just use to_pci_dev(dev) . Thanks Vaibhav Gupta