From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753289AbbI3IqH (ORCPT ); Wed, 30 Sep 2015 04:46:07 -0400 Received: from mga14.intel.com ([192.55.52.115]:39427 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750768AbbI3IqB (ORCPT ); Wed, 30 Sep 2015 04:46:01 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,611,1437462000"; d="scan'208";a="800338434" Date: Wed, 30 Sep 2015 11:45:57 +0300 From: Mika Westerberg To: Benjamin Tissoires Cc: Jiri Kosina , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] HID: multitouch: Fetch feature reports on demand for Win8 devices Message-ID: <20150930084557.GE1551@lahna.fi.intel.com> References: <1443451630-144023-1-git-send-email-mika.westerberg@linux.intel.com> <20150929090431.GA30386@mail.corp.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150929090431.GA30386@mail.corp.redhat.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 29, 2015 at 05:04:31AM -0400, Benjamin Tissoires wrote: > > +static void mt_get_feature(struct hid_device *hdev, struct hid_report *report) > > +{ > > + int ret, size = hid_report_len(report); > > + u8 *buf; > > + > > + /* > > + * Only fetch the feature report if initial reports are not already > > + * been retrieved. Currently this is only done for Windows 8 touch > > + * devices. > > + */ > > + if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS)) > > + return; > > Some Win 7 panels have this quirk set too because they do not support > either querying random feature or input reports. > > I think this test is safe given that this is, I think, what the Windows > driver does (I remember that it queries for the features it needs). > However I am not 100% sure if this will not break one low quality > touchscreen. > > I would be in favor of applying the patch in its current shape, but if > Jiri thinks we need a little bit more caution here, we would need to add > a test regarding the Win8 capability here. What about adding following on top of this patch? It checks the device in question belongs to "win8 class". I can send a new version of the patch if this seems reasonable. diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c index d9ca2b96ab68..72c55a3f650f 100644 --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -311,6 +311,7 @@ static struct attribute_group mt_attribute_group = { static void mt_get_feature(struct hid_device *hdev, struct hid_report *report) { + struct mt_device *td = hid_get_drvdata(hdev); int ret, size = hid_report_len(report); u8 *buf; @@ -319,7 +320,8 @@ static void mt_get_feature(struct hid_device *hdev, struct hid_report *report) * been retrieved. Currently this is only done for Windows 8 touch * devices. */ - if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS)) + if (!(hdev->quirks & HID_QUIRK_NO_INIT_REPORTS) || + td->mtclass.name != MT_CLS_WIN_8) return; buf = hid_alloc_report_buf(report, GFP_KERNEL);