From patchwork Fri Dec 11 02:18:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hui Wang X-Patchwork-Id: 342900 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 166F8C4361B for ; Fri, 11 Dec 2020 02:19:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1F2323E54 for ; Fri, 11 Dec 2020 02:19:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389575AbgLKCTL (ORCPT ); Thu, 10 Dec 2020 21:19:11 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:58854 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389595AbgLKCTE (ORCPT ); Thu, 10 Dec 2020 21:19:04 -0500 Received: from [123.114.42.209] (helo=localhost.localdomain) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1knY0j-0001c9-VC; Fri, 11 Dec 2020 02:18:22 +0000 From: Hui Wang To: linux-acpi@vger.kernel.org, rafael.j.wysocki@intel.com Cc: lenb@kernel.org Subject: [PATCH v4] ACPI / PNP: compare the string length in the matching_id Date: Fri, 11 Dec 2020 10:18:14 +0800 Message-Id: <20201211021814.36193-1-hui.wang@canonical.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Recently we met a touchscreen problem on some Thinkpad machines, the touchscreen driver (i2c-hid) is not loaded and the touchscreen can't work. An i2c ACPI device with the name WACF2200 is defined in the BIOS, with the current rule in matching_id(), this device will be regarded as a PNP device since there is WACFXXX in the acpi_pnp_device_ids[] and this PNP device is attached to the acpi device as the 1st physical_node, this will make the i2c bus match fail when i2c bus calls acpi_companion_match() to match the acpi_id_table in the i2c-hid driver. WACF2200 is an i2c device instead of a PNP device, after adding the string length comparing, the matching_id() will return false when matching WACF2200 and WACFXXX, and it is reasonable to compare the string length when matching two ids. Cc: stable@vger.kernel.org Signed-off-by: Hui Wang --- Sorry, the v3 patch has mis-spelling word in the commit header, so fix it and send the v4 patch. drivers/acpi/acpi_pnp.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/acpi/acpi_pnp.c b/drivers/acpi/acpi_pnp.c index 4ed755a963aa..8f2dc176bb41 100644 --- a/drivers/acpi/acpi_pnp.c +++ b/drivers/acpi/acpi_pnp.c @@ -319,6 +319,9 @@ static bool matching_id(const char *idstr, const char *list_id) { int i; + if (strlen(idstr) != strlen(list_id)) + return false; + if (memcmp(idstr, list_id, 3)) return false;