From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lv Zheng Subject: [PATCH v3] ACPI / EC: Fix an order issue in ec_remove_handlers() Date: Fri, 8 Jul 2016 09:25:05 +0800 Message-ID: <197d3c522b51e8c07156d0496fd9bb48e580d984.1467940972.git.lv.zheng@intel.com> References: <20160706141410.GA1430@tetsubishi> Return-path: Received: from mga04.intel.com ([192.55.52.120]:15686 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753401AbcGHBZT (ORCPT ); Thu, 7 Jul 2016 21:25:19 -0400 In-Reply-To: <20160706141410.GA1430@tetsubishi> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Len Brown Cc: Lv Zheng , Lv Zheng , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org There is an order issue in ec_remove_handlers() that the functions invoked in it are not able to handle the current restrictions (see comments below). If ec_remove_handlers() is invoked during runtime after _REG(CONNECT) is invoked, this issue will be uncovered. Link: https://bugzilla.kernel.org/show_bug.cgi?id=102421 Reported-and-tested-by: Wolfram Sang Reported-by: Nicholas Signed-off-by: Lv Zheng --- drivers/acpi/ec.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index b1050a0..84073a6 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -1331,8 +1331,6 @@ static int ec_install_handlers(struct acpi_ec *ec) static void ec_remove_handlers(struct acpi_ec *ec) { - acpi_ec_stop(ec, false); - if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) { if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle, ACPI_ADR_SPACE_EC, &acpi_ec_space_handler))) @@ -1340,6 +1338,19 @@ static void ec_remove_handlers(struct acpi_ec *ec) clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags); } + /* + * Stops handling the EC transactions after removing the operation + * region handler. This is required because _REG(DISCONNECT) + * invoked during the removal can result in new EC transactions. + * + * Flushes the EC requests and thus disables the GPE before + * removing the GPE handler. This is required by the current ACPICA + * GPE core. ACPICA GPE core will automatically disable a GPE when + * it is indicated but there is no way to handle it. So the drivers + * must disable the GPEs prior than removing the GPE handlers. + */ + acpi_ec_stop(ec, false); + if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) { if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler))) -- 1.7.10