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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 68C81C432C3 for ; Tue, 19 Nov 2019 16:09:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B1AD22365 for ; Tue, 19 Nov 2019 16:09:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728333AbfKSQJV (ORCPT ); Tue, 19 Nov 2019 11:09:21 -0500 Received: from mga14.intel.com ([192.55.52.115]:8324 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727909AbfKSQJV (ORCPT ); Tue, 19 Nov 2019 11:09:21 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Nov 2019 08:09:21 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,218,1571727600"; d="scan'208";a="215567282" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.163]) by fmsmga001.fm.intel.com with SMTP; 19 Nov 2019 08:09:18 -0800 Received: by lahna (sSMTP sendmail emulation); Tue, 19 Nov 2019 18:09:17 +0200 Date: Tue, 19 Nov 2019 18:09:17 +0200 From: Mika Westerberg To: Hans de Goede Cc: Andy Shevchenko , Bartosz Golaszewski , Linus Walleij , linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2] pinctrl: baytrail: Really serialize all register accesses Message-ID: <20191119160917.GM11621@lahna.fi.intel.com> References: <20191119154641.202139-1-hdegoede@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191119154641.202139-1-hdegoede@redhat.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Tue, Nov 19, 2019 at 04:46:41PM +0100, Hans de Goede wrote: > Commit 39ce8150a079 ("pinctrl: baytrail: Serialize all register access") > added a spinlock around all register accesses because: > > "There is a hardware issue in Intel Baytrail where concurrent GPIO register > access might result reads of 0xffffffff and writes might get dropped > completely." > > Testing has shown that this does not catch all cases, there are still > 2 problems remaining > > 1) The original fix uses a spinlock per byt_gpio device / struct, > additional testing has shown that this is not sufficient concurent > accesses to 2 different GPIO banks also suffer from the same problem. > > This commit fixes this by moving to a single global lock. > > 2) The original fix did not add a lock around the register accesses in > the suspend/resume handling. > > Since pinctrl-baytrail.c is using normal suspend/resume handlers, > interrupts are still enabled during suspend/resume handling. Nothing > should be using the GPIOs when they are being taken down, _but_ the > GPIOs themselves may still cause interrupts, which are likely to > use (read) the triggering GPIO. So we need to protect against > concurrent GPIO register accesses in the suspend/resume handlers too. > > This commit fixes this by adding the missing spin_lock / unlock calls. > > The 2 fixes together fix the Acer Switch 10 SW5-012 getting completely > confused after a suspend resume. The DSDT for this device has a bug > in its _LID method which reprograms the home and power button trigger- > flags requesting both high and low _level_ interrupts so the IRQs for > these 2 GPIOs continuously fire. This combined with the saving of > registers during suspend, triggers concurrent GPIO register accesses > resulting in saving 0xffffffff as pconf0 value during suspend and then > when restoring this on resume the pinmux settings get all messed up, > resulting in various I2C busses being stuck, the wifi no longer working > and often the tablet simply not coming out of suspend at all. > > Cc: stable@vger.kernel.org > Fixes: 39ce8150a079 ("pinctrl: baytrail: Serialize all register access") > Signed-off-by: Hans de Goede Acked-by: Mika Westerberg