From patchwork Mon May 12 00:13:11 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 4153441 Return-Path: X-Original-To: patchwork-linux-acpi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 1C6C8BFF02 for ; Sun, 11 May 2014 23:56:31 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3C5452018B for ; Sun, 11 May 2014 23:56:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A84B2017E for ; Sun, 11 May 2014 23:56:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757351AbaEKX41 (ORCPT ); Sun, 11 May 2014 19:56:27 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:61868 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753795AbaEKX41 (ORCPT ); Sun, 11 May 2014 19:56:27 -0400 Received: from afdm111.neoplus.adsl.tpnet.pl [95.49.90.111] (HELO vostro.rjw.lan) by serwer1319399.home.pl [79.96.170.134] with SMTP (IdeaSmtpServer v0.80) id fbebcaa0b88d670c; Mon, 12 May 2014 01:56:25 +0200 From: "Rafael J. Wysocki" To: ACPI Devel Maling List Cc: Linux Kernel Mailing List , Jiang Liu , James Duley , Phillip Dixon , Brandon Casey Subject: [PATCH] ACPI / TPM: Fix resume regression on Chromebooks Date: Mon, 12 May 2014 02:13:11 +0200 Message-ID: <1815337.lCisGfjnvC@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.14.0-rc7+; KDE/4.11.5; x86_64; ; ) MIME-Version: 1.0 Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rafael J. Wysocki Chromebooks (at least Acer C720 and Pixel) implement an ACPI object for TPM, but don't implement the _DSM method to support PPI. As a result, the TPM driver fails to load on those machines after commit 1569a4c4ceba (ACPI / TPM: detect PPI features by checking availability of _DSM functions) which causes them to fail to resume from system suspend, becuase they require the TPM hardware to be put into the right state during resume and the TPM driver is necessary for that. Fix the problem by making tpm_add_ppi() return 0 when tpm_ppi_handle is still NULL after walking the ACPI namespace in search for the PPI _DSM, which allows the TPM driver to load and operate the hardware (during system resume in particular), but avoid creating the PPI sysfs group in that case. This change is based on a prototype patch from Jiang Liu. Fixes: 1569a4c4ceba (ACPI / TPM: detect PPI features by checking availability of _DSM functions) References: https://bugzilla.kernel.org/show_bug.cgi?id=74021 Reported-by: James Duley Reported-by: Phillip Dixon Tested-by: Brandon Casey Cc: 3.14+ # 3.14+ Signed-off-by: Rafael J. Wysocki --- drivers/char/tpm/tpm_ppi.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: linux-pm/drivers/char/tpm/tpm_ppi.c =================================================================== --- linux-pm.orig/drivers/char/tpm/tpm_ppi.c +++ linux-pm/drivers/char/tpm/tpm_ppi.c @@ -328,13 +328,11 @@ int tpm_add_ppi(struct kobject *parent) /* Cache TPM ACPI handle and version string */ acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX, ppi_callback, NULL, NULL, &tpm_ppi_handle); - if (tpm_ppi_handle == NULL) - return -ENODEV; - - return sysfs_create_group(parent, &ppi_attr_grp); + return tpm_ppi_handle ? sysfs_create_group(parent, &ppi_attr_grp) : 0; } void tpm_remove_ppi(struct kobject *parent) { - sysfs_remove_group(parent, &ppi_attr_grp); + if (tpm_ppi_handle) + sysfs_remove_group(parent, &ppi_attr_grp); }