Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752119AbdDJTll (ORCPT ); Mon, 10 Apr 2017 15:41:41 -0400 Received: from us-mx1.synaptics.com ([192.147.44.131]:32052 "EHLO us-mx1.synaptics.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751780AbdDJTlj (ORCPT ); Mon, 10 Apr 2017 15:41:39 -0400 Subject: Re: Crash caused by hid-rmi and no longer working touchscreen To: Dmitry Torokhov , Jiri Kosina References: <20170410183802.GA39262@dtor-ws> CC: Gabriele Mazzotta , , "linux-kernel@vger.kernel.org" , , Peter Hutterer , Cameron Gutman , Thorsten Leemhuis , Nick Dyer , Christopher Heiny From: Andrew Duggan Message-ID: Date: Mon, 10 Apr 2017 12:41:38 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170410183802.GA39262@dtor-ws> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.4.10.103] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2458 Lines: 57 On 04/10/2017 11:38 AM, Dmitry Torokhov wrote: > On Mon, Apr 10, 2017 at 03:18:03PM +0200, Jiri Kosina wrote: >> [ a couple more people from "the other regression thread" added to CC ] >> >> On Mon, 10 Apr 2017, Gabriele Mazzotta wrote: >> >>> Hi, >>> >>> I'm having troubles with hid-rmi using 4.11-rc6. I'm getting some >>> "rmi_hid_read_block: timeout elapsed" errors and ultimately the >>> crash you can see at the end of this mail. I will reply to this >>> mail with a full log that shows all the errors. >>> >>> The problem seems to be caused by commit 279967a65b320d174a507498ae >>> ("HID: rmi: Handle all Synaptics touchpads using hid-rmi"). >>> >>> My laptop has a Synaptics touchpad and a Synaptics touchscreen. >>> Because of that commit, hid-rmi is used for both the devices, while >>> it has always been used only for the touchpad. Needless to say that >>> the touchscreen no longer works. >>> >>> If I revert that commit, everything goes back to normal. >> Alright, given this is a second regression cause by this switch, I suggest >> to revert this one for 4.11 still, and work on fixing this properly for >> 4.12. >> >> If noone raises any objections (a few more people added to Cc), I'll queue >> a 4.11-rc revert tomorrow. > Yes, we also have this: > > https://bugzilla.kernel.org/show_bug.cgi?id=195287 I suspect that the issue might be that both of these touchscreens have the HID_GD_POINTER usage defined in their HID report descriptor. This might be because the firmware is configured to support pens. It looks like the Asus T302CA from the bug does have a pen and the XPS13 9333 may simply have firmware which has pen support enabled. The HID_GD_POINTER usage is used in hid-core to differentiate between touchpads and touchscreens. So if a touchscreen has HID_GD_POINTER defined then hid-core will bind hid-rmi to it. None, of my test systems have pen support so I did not anticipate this. Also, the reason why we can't just support touchscreens using hid-rmi is because the firmware for HID touchscreens lacks the functionality of reporting the attention data (finger positions) in a single report. It ends up being less efficient to run HID touchscreens in RMI mode. > so reverting seems prudent at this time. Yes, I agree we should revert the commit. There simply isn't enough time to come up with and test a new method for differentiating touchpads and touchscreens before 4.11 is released. Andrew > Thanks. >