From patchwork Tue Sep 1 13:22:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jean Delvare X-Patchwork-Id: 254866 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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_SANE_2 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 CDE4DC433E7 for ; Tue, 1 Sep 2020 13:23:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACFFA20767 for ; Tue, 1 Sep 2020 13:23:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727796AbgIANW7 convert rfc822-to-8bit (ORCPT ); Tue, 1 Sep 2020 09:22:59 -0400 Received: from mx2.suse.de ([195.135.220.15]:57516 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728126AbgIANW3 (ORCPT ); Tue, 1 Sep 2020 09:22:29 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 06D8DB016; Tue, 1 Sep 2020 13:22:23 +0000 (UTC) Date: Tue, 1 Sep 2020 15:22:21 +0200 From: Jean Delvare To: Linux I2C Cc: Volker =?utf-8?q?R=C3=BCmelin?= , Bjorn Helgaas , Vaibhav Gupta , Wolfram Sang Subject: [PATCH v2 1/2] i2c: i801: Fix resume bug Message-ID: <20200901152221.3cea0048@endymion> Organization: SUSE Linux X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-suse-linux-gnu) MIME-Version: 1.0 Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org 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, moved the write into i801_setup_hstcfg.] 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 inititialize 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. Changes since v1: * Move the write into i801_setup_hstcfg() itself (suggested by Wolfram Sang). * Pass struct i801_priv * as the parameter to i801_setup_hstcfg(). It includes everything we need. drivers/i2c/busses/i2c-i801.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) --- linux-5.8.orig/drivers/i2c/busses/i2c-i801.c 2020-08-31 15:09:29.221616330 +0200 +++ linux-5.8/drivers/i2c/busses/i2c-i801.c 2020-09-01 12:42:46.003491616 +0200 @@ -1709,6 +1709,16 @@ static inline int i801_acpi_probe(struct static inline void i801_acpi_remove(struct i801_priv *priv) { } #endif +static unsigned char i801_setup_hstcfg(struct i801_priv *priv) +{ + unsigned char hstcfg = priv->original_hstcfg; + + hstcfg &= ~SMBHSTCFG_I2C_EN; /* SMBus timing */ + hstcfg |= SMBHSTCFG_HST_EN; + pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hstcfg); + return hstcfg; +} + static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id) { unsigned char temp; @@ -1830,14 +1840,10 @@ static int i801_probe(struct pci_dev *de return err; } - pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &temp); - priv->original_hstcfg = temp; - temp &= ~SMBHSTCFG_I2C_EN; /* SMBus timing */ - if (!(temp & SMBHSTCFG_HST_EN)) { + pci_read_config_byte(priv->pci_dev, SMBHSTCFG, &priv->original_hstcfg); + temp = i801_setup_hstcfg(priv); + if (!(priv->original_hstcfg & SMBHSTCFG_HST_EN)) dev_info(&dev->dev, "Enabling SMBus device\n"); - temp |= SMBHSTCFG_HST_EN; - } - pci_write_config_byte(priv->pci_dev, SMBHSTCFG, temp); if (temp & SMBHSTCFG_SMB_SMI_EN) { dev_dbg(&dev->dev, "SMBus using interrupt SMI#\n"); @@ -1963,6 +1969,7 @@ static int i801_resume(struct device *de { struct i801_priv *priv = dev_get_drvdata(dev); + i801_setup_hstcfg(priv); i801_enable_host_notify(&priv->adapter); return 0;