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=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 98A8DC43215 for ; Thu, 14 Nov 2019 07:37:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75F5C206DB for ; Thu, 14 Nov 2019 07:37:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725920AbfKNHhM (ORCPT ); Thu, 14 Nov 2019 02:37:12 -0500 Received: from mga12.intel.com ([192.55.52.136]:62695 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725852AbfKNHhL (ORCPT ); Thu, 14 Nov 2019 02:37:11 -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 fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Nov 2019 23:37:11 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,302,1569308400"; d="scan'208";a="214485166" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.163]) by fmsmga001.fm.intel.com with SMTP; 13 Nov 2019 23:37:07 -0800 Received: by lahna (sSMTP sendmail emulation); Thu, 14 Nov 2019 09:37:06 +0200 Date: Thu, 14 Nov 2019 09:37:06 +0200 From: Mika Westerberg To: Hans de Goede Cc: Jarkko Nikula , Wolfram Sang , linux-i2c@vger.kernel.org, linux-acpi@vger.kernel.org, youling 257 Subject: Re: [PATCH v2] i2c: acpi: Force bus speed to 400KHz if a Silead touchscreen is present Message-ID: <20191114073706.GG34425@lahna.fi.intel.com> References: <20191113182938.279299-1-hdegoede@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191113182938.279299-1-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 Wed, Nov 13, 2019 at 07:29:38PM +0100, Hans de Goede wrote: > Many cheap devices use Silead touchscreen controllers. Testing has shown > repeatedly that these touchscreen controllers work fine at 400KHz, but for > unknown reasons do not work properly at 100KHz. This has been seen on > both ARM and x86 devices using totally different i2c controllers. > > On some devices the ACPI tables list another device at the same I2C-bus > as only being capable of 100KHz, testing has shown that these other > devices work fine at 400KHz (as can be expected of any recent I2C hw). > > This commit makes i2c_acpi_find_bus_speed() always return 400KHz if a > Silead touchscreen controller is present, fixing the touchscreen not > working on devices which ACPI tables' wrongly list another device on the > same bus as only being capable of 100KHz. > > Specifically this fixes the touchscreen on the Jumper EZpad 6 m4 not > working. > > Reported-and-tested-by: youling 257 > Signed-off-by: Hans de Goede Acked-by: Mika Westerberg