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,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 0AF99C432C3 for ; Thu, 14 Nov 2019 20:48:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DDFD920718 for ; Thu, 14 Nov 2019 20:48:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726818AbfKNUsS (ORCPT ); Thu, 14 Nov 2019 15:48:18 -0500 Received: from sauhun.de ([88.99.104.3]:44928 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726812AbfKNUsS (ORCPT ); Thu, 14 Nov 2019 15:48:18 -0500 Received: from localhost (x4dbf5278.dyn.telefonica.de [77.191.82.120]) by pokefinder.org (Postfix) with ESMTPSA id 466512C03EE; Thu, 14 Nov 2019 21:48:16 +0100 (CET) Date: Thu, 14 Nov 2019 21:48:15 +0100 From: Wolfram Sang To: Hans de Goede Cc: Jarkko Nikula , Mika Westerberg , 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: <20191114204815.GC7213@kunai> References: <20191113182938.279299-1-hdegoede@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ghzN8eJ9Qlbqn3iT" Content-Disposition: inline In-Reply-To: <20191113182938.279299-1-hdegoede@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org --ghzN8eJ9Qlbqn3iT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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. >=20 > 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). >=20 > 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. >=20 > Specifically this fixes the touchscreen on the Jumper EZpad 6 m4 not > working. >=20 > Reported-and-tested-by: youling 257 > Signed-off-by: Hans de Goede Stable material, I'd say? > + dev_warn(dev, FW_BUG "DSDT wrongly sets I2C bus speed to %d, forcing = it to %d\n", > + lookup.min_speed, lookup.force_speed); I have not a strong opinion here. However, does the DSDT really wrongly set a bus speed when it is the touchscreen controller which cannot handle lower speeds and other devies are specified to run at 100kHz? --ghzN8eJ9Qlbqn3iT Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAl3NvYsACgkQFA3kzBSg KbYJCQ/9FqC8J9oFxbGEj51s5iUyX9BadmqLXv5/c/ndwbh+WmdO4tlHQQeE/L+S wjx1ijKRkv41Scht+lEp+tCSN04TnRE7ODk76sZ4wbGyJ83b1n2VNRZ+VfDXpoxu BnXeW/tthWuPInXhsTBEmzd/5B7AoV1xMWgTik4ALUshCE4MuxGG2w7lJBlD1EsI u5LmGUdPEwPvXGdq6VVCqF5+pjMGitLumuo5bKa+/3JdQcqHZEkayDkRB8Eqy+L4 ZskpUWzEsL6NcZRIPcWXeHHgKPuAeF7EnlaecuzNos+Kh2EzsgL5L6CzzLCAhZuM rKlliCxMPOJCMGaGTQ3MBogc8MMtvSkySmuVK3vU1x79Ze4axStbIi3i9GBVsk5g AORxucKaJNZm/O4I0viSRoX3VovfJaTEiFwffEVwU2QjwbwgWNH8Q5ws0sSxrarA bquNJnrDbK6igoLa0v4SWtg89p9CbaoWiAK2pihWMX8QBCvYtyrhQbGXi+DRbYXK 1KTokqs+OTZ1/jVYyPIry//o8VbC1JwZaETi49tKLEZw+141dFh9tdJC+b/meNBs CQWDfWjz1AYyHcbr02J6KY4GeqsKhn/5WLgfKJjprAEKVC2JHZcs4xYGCyj+wENA +9A1yT2HdXZeK87gLLsqJNqLnwCu0gKS/1sWIOQKzsgw7Kx82YQ= =2fQO -----END PGP SIGNATURE----- --ghzN8eJ9Qlbqn3iT--