From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753586AbcGUQxs (ORCPT ); Thu, 21 Jul 2016 12:53:48 -0400 Received: from ao2.it ([92.243.12.208]:48692 "EHLO ao2.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753396AbcGUQxm (ORCPT ); Thu, 21 Jul 2016 12:53:42 -0400 X-Greylist: delayed 1132 seconds by postgrey-1.27 at vger.kernel.org; Thu, 21 Jul 2016 12:53:42 EDT Date: Thu, 21 Jul 2016 18:34:39 +0200 From: Antonio Ospite To: Mikko Perttunen Cc: Benjamin Tissoires , jikos@kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Mikko Perttunen Subject: Re: [PATCH] HID: sony: disable descriptor fixup for FutureMax Dance Mat Message-Id: <20160721183439.3edddbc6312555afda517f8c@ao2.it> In-Reply-To: <78cafd15-850f-3110-f63e-bb41f6b69c5c@kapsi.fi> References: <20160717172533.8777-1-mikko.perttunen@kapsi.fi> <20160718142837.GK4663@mail.corp.redhat.com> <78cafd15-850f-3110-f63e-bb41f6b69c5c@kapsi.fi> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu) X-Face: z*RaLf`X<@C75u6Ig9}{oW$H;1_\2t5)({*|jhM/Vb;]yA5\I~93>J<_`<4)A{':UrE Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 19 Jul 2016 09:08:27 +0300 Mikko Perttunen wrote: > On 07/18/16 17:28, Benjamin Tissoires wrote: [...] > > > > Also, I think it would be better to have a check on the existing report > > descriptor instead of blindly fixing it. Other drivers make sure they > > are fixing the correct region before overriding it, but I think using a > > md5sum might be just easier (though that's not required for your patch I > > think). > > I agree. In fact, the mat used to work back in 3.15 when the driver did > some rudimentary checks before overwriting the descriptor. In any case, > it would be difficult for me to add the checks since the mat is the only > piece of hardware I own that is handled by this driver. > The fact that the report gets fixed up unconditionally is from commit c607fb8 (HID: sony: Always override the Sixaxis descriptor). The rationale behind this change was that compatible devices are supposed to send exactly the same _raw_ data as the original ones, so overriding the _whole_ descriptor unconditionally should keep them working. I would be interesting to understand why some (supposedly) compatible devices break, maybe they rely on the fact that the PS3 would use the original report? BTW I'd slightly prefer the current way of having a straight path for the common case (original and actually compatible devices) and handle the exceptions explicitly using quirks, but I am open to changes and I can test patches with some original controllers if needed. Ciao ciao, Antonio -- Antonio Ospite http://ao2.it A: Because it messes up the order in which people normally read text. See http://en.wikipedia.org/wiki/Posting_style Q: Why is top-posting such a bad thing?