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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 85826C34026 for ; Tue, 18 Feb 2020 20:00:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5387124125 for ; Tue, 18 Feb 2020 20:00:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582056044; bh=zFBPkorORv1mDODvlEy84IkG/6oz+vyKN4G57irLDDI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZRc8dU8/0xzWPj9ajTuNjtGlb1tjbxrMysrTC4bVTMvSoxtOBjfcI4TnCjVQzJSCi K5RxRY+BnD4N/X7WKnb6zIYKR7yuXhL5ob7IwNBlXMW69yyHjUit4RQwPwIbgarqqJ 80S7xc/wr/9gKh8D44ma310/qKlYPlDfzpoq25K0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728650AbgBRUAm (ORCPT ); Tue, 18 Feb 2020 15:00:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:40038 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728064AbgBRUAk (ORCPT ); Tue, 18 Feb 2020 15:00:40 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4E8492464E; Tue, 18 Feb 2020 20:00:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582056039; bh=zFBPkorORv1mDODvlEy84IkG/6oz+vyKN4G57irLDDI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nyVKbcL3sD65msr0/t0pp+o8unEeLxzd4QNVM0V9lvULoCwbJAUiHVwAvRA6yaNRl qC8FiZrexwhbQJX5B1DnLH1k0uCmJ9REeD+gqyNkKZ/Ts35gJvv79pPIou8Hs7lP2E fMggKyHfx3wrwz0+GQ98ta63TS8lJVQ8YT426WQA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Rafael J. Wysocki" Subject: [PATCH 5.5 12/80] ACPI: EC: Fix flushing of pending work Date: Tue, 18 Feb 2020 20:54:33 +0100 Message-Id: <20200218190433.261249514@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200218190432.043414522@linuxfoundation.org> References: <20200218190432.043414522@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki commit f0ac20c3f6137910c8a927953e8a92f5b3716166 upstream. Commit 016b87ca5c8c ("ACPI: EC: Rework flushing of pending work") introduced a subtle bug into the flushing of pending EC work while suspended to idle, which may cause the EC driver to fail to re-enable the EC GPE after handling a non-wakeup event (like a battery status change event, for example). The problem is that the work item flushed by flush_scheduled_work() in __acpi_ec_flush_work() may disable the EC GPE and schedule another work item expected to re-enable it, but that new work item is not flushed, so __acpi_ec_flush_work() returns with the EC GPE disabled and the CPU running it goes into an idle state subsequently. If all of the other CPUs are in idle states at that point, the EC GPE won't be re-enabled until at least one CPU is woken up by another interrupt source, so system wakeup events that would normally come from the EC then don't work. This is reproducible on a Dell XPS13 9360 in my office which sometimes stops reacting to power button and lid events (triggered by the EC on that machine) after switching from AC power to battery power or vice versa while suspended to idle (each of those switches causes the EC GPE to trigger for several times in a row, but they are not system wakeup events). To avoid this problem, it is necessary to drain the workqueue entirely in __acpi_ec_flush_work(), but that cannot be done with respect to system_wq, because work items may be added to it from other places while __acpi_ec_flush_work() is running. For this reason, make the EC driver use a dedicated workqueue for EC events processing (let that workqueue be ordered so that EC events are processed sequentially) and use drain_workqueue() on it in __acpi_ec_flush_work(). Fixes: 016b87ca5c8c ("ACPI: EC: Rework flushing of pending work") Cc: 5.4+ # 5.4+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/acpi/ec.c | 44 ++++++++++++++++++++++++++------------------ 1 file changed, 26 insertions(+), 18 deletions(-) --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -179,6 +179,7 @@ EXPORT_SYMBOL(first_ec); static struct acpi_ec *boot_ec; static bool boot_ec_is_ecdt = false; +static struct workqueue_struct *ec_wq; static struct workqueue_struct *ec_query_wq; static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */ @@ -469,7 +470,7 @@ static void acpi_ec_submit_query(struct ec_dbg_evt("Command(%s) submitted/blocked", acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY)); ec->nr_pending_queries++; - schedule_work(&ec->work); + queue_work(ec_wq, &ec->work); } } @@ -535,7 +536,7 @@ static void acpi_ec_enable_event(struct #ifdef CONFIG_PM_SLEEP static void __acpi_ec_flush_work(void) { - flush_scheduled_work(); /* flush ec->work */ + drain_workqueue(ec_wq); /* flush ec->work */ flush_workqueue(ec_query_wq); /* flush queries */ } @@ -556,8 +557,8 @@ static void acpi_ec_disable_event(struct void acpi_ec_flush_work(void) { - /* Without ec_query_wq there is nothing to flush. */ - if (!ec_query_wq) + /* Without ec_wq there is nothing to flush. */ + if (!ec_wq) return; __acpi_ec_flush_work(); @@ -2115,25 +2116,33 @@ static struct acpi_driver acpi_ec_driver .drv.pm = &acpi_ec_pm, }; -static inline int acpi_ec_query_init(void) +static void acpi_ec_destroy_workqueues(void) { - if (!ec_query_wq) { - ec_query_wq = alloc_workqueue("kec_query", 0, - ec_max_queries); - if (!ec_query_wq) - return -ENODEV; + if (ec_wq) { + destroy_workqueue(ec_wq); + ec_wq = NULL; } - return 0; -} - -static inline void acpi_ec_query_exit(void) -{ if (ec_query_wq) { destroy_workqueue(ec_query_wq); ec_query_wq = NULL; } } +static int acpi_ec_init_workqueues(void) +{ + if (!ec_wq) + ec_wq = alloc_ordered_workqueue("kec", 0); + + if (!ec_query_wq) + ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries); + + if (!ec_wq || !ec_query_wq) { + acpi_ec_destroy_workqueues(); + return -ENODEV; + } + return 0; +} + static const struct dmi_system_id acpi_ec_no_wakeup[] = { { .ident = "Thinkpad X1 Carbon 6th", @@ -2164,8 +2173,7 @@ int __init acpi_ec_init(void) int result; int ecdt_fail, dsdt_fail; - /* register workqueue for _Qxx evaluations */ - result = acpi_ec_query_init(); + result = acpi_ec_init_workqueues(); if (result) return result; @@ -2196,6 +2204,6 @@ static void __exit acpi_ec_exit(void) { acpi_bus_unregister_driver(&acpi_ec_driver); - acpi_ec_query_exit(); + acpi_ec_destroy_workqueues(); } #endif /* 0 */