Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756280AbcCWTfE (ORCPT ); Wed, 23 Mar 2016 15:35:04 -0400 Received: from mail-ob0-f196.google.com ([209.85.214.196]:36802 "EHLO mail-ob0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755798AbcCWTfB (ORCPT ); Wed, 23 Mar 2016 15:35:01 -0400 MIME-Version: 1.0 In-Reply-To: References: <1457372672-884-1-git-send-email-a.mathur@samsung.com> <56E17A73.8090901@bitmath.org> Date: Thu, 24 Mar 2016 01:05:00 +0530 Message-ID: Subject: Re: [PATCH] Input: Do not add SYN_REPORT in between a single packet data From: Aniroop Mathur To: Dmitry Torokhov , Henrik Rydberg Cc: Aniroop Mathur , "linux-input@vger.kernel.org" , lkml Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2696 Lines: 71 Hello Mr. Torokhov / Mr. Henry, On Wed, Mar 16, 2016 at 11:54 PM, Aniroop Mathur wrote: > Hello Mr. Torokhov, > > Could you kindly help to update about this patch? > So is this patch concluded? Are you applying it? Thanks, Aniroop Mathur > Thank you, > Aniroop Mathur > > > On Fri, Mar 11, 2016 at 12:26 AM, Aniroop Mathur > wrote: >> Hi Henrik, >> >> On Thu, Mar 10, 2016 at 7:15 PM, Henrik Rydberg wrote: >>> Hi Dmitry, >>> >>>>> diff --git a/drivers/input/input.c b/drivers/input/input.c >>>>> index 8806059..262ef77 100644 >>>>> --- a/drivers/input/input.c >>>>> +++ b/drivers/input/input.c >>>>> @@ -401,8 +401,7 @@ static void input_handle_event(struct input_dev *dev, >>>>> if (dev->num_vals >= 2) >>>>> input_pass_values(dev, dev->vals, dev->num_vals); >>>>> dev->num_vals = 0; >>>>> - } else if (dev->num_vals >= dev->max_vals - 2) { >>>>> - dev->vals[dev->num_vals++] = input_value_sync; >>>>> + } else if (dev->num_vals >= dev->max_vals - 1) { >>>>> input_pass_values(dev, dev->vals, dev->num_vals); >>>>> dev->num_vals = 0; >>>>> } >>>> >>>> This makes sense to me. Henrik? >>> >>> I went through the commits that made these changes, and I cannot see any strong >>> reason to keep it. However, this code path only triggers if no SYN events are >>> seen, as in a driver that fails to emit them and consequently fills up the >>> buffer. In other words, this change would only affect a device that is already, >>> to some degree, broken. >>> >>> So, the question to Aniroop is: do you see this problem in practise, and in that >>> case, for what driver? >>> >> >> Nope. So far I have not dealt with any such driver. >> I made this change because it is breaking protocol of SYN_REPORT event code. >> >> Further from the code, I could deduce that max_vals is just an estimation of >> packet_size and it does not guarantee that packet_size is same as max_vals. >> So real packet_size can be more than max_vals value and hence we could not >> insert SYN_REPORT until packet ends really. >> Further, if we consider that there exists a driver or will exist in future >> which sets capability of x event code according to which max_value comes out to >> y and the real packet size is z i.e. driver wants to send same event codes >> again in the same packet, so input event reader would be expecting SYN_REPORT >> after z events but due to current code SYN_REPORT will get inserted >> automatically after y events, which is a wrong behaviour. >> >> Thanks, >> Aniroop Mathur >> >>> Henrik >>>