From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:27151 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750736Ab1IAFxU (ORCPT ); Thu, 1 Sep 2011 01:53:20 -0400 Message-ID: <4E5F1DCA.3000804@redhat.com> Date: Thu, 01 Sep 2011 02:53:14 -0300 From: Mauro Carvalho Chehab MIME-Version: 1.0 To: Thierry Reding CC: linux-media@vger.kernel.org Subject: Re: [PATCH 16/21] [staging] tm6000: Select interface on first open. References: <1312442059-23935-1-git-send-email-thierry.reding@avionic-design.de> <1312442059-23935-17-git-send-email-thierry.reding@avionic-design.de> <4E5E934A.7000500@redhat.com> <20110901051945.GD18473@avionic-0098.mockup.avionic-design.de> In-Reply-To: <20110901051945.GD18473@avionic-0098.mockup.avionic-design.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Em 01-09-2011 02:19, Thierry Reding escreveu: > * Mauro Carvalho Chehab wrote: >> Em 04-08-2011 04:14, Thierry Reding escreveu: >>> Instead of selecting the default interface setting when preparing >>> isochronous transfers, select it on the first call to open() to make >>> sure it is available earlier. >> >> Hmm... I fail to see what this is needed earlier. The ISOC endpont is used >> only when the device is streaming. >> >> Did you get any bug related to it? If so, please describe it better. > > I'm not sure whether this really fixes a bug, but it seems a little wrong to > me to selecting the interface so late in the process when in fact the device > is already being configured before (video standard, audio mode, firmware > upload, ...). Some applications may open the device just to change the controls. All other drivers only set alternates/interfaces when the streaming is requested, as alternates/interfaces are needed only there. > Thinking about it, this may actually be part of the fix for the "device hangs > sometimes for inexplicable reasons" bug that this whole patch series seems to > fix. It is unlikely, except if the firmware inside the chip is broken (unfortunately, we have serious reasons to believe that the internal firmware on this chipset has serious bugs). I prefer to not apply this patch, except if we have a good reason for that, as otherwise this driver will behave different than the others. Regards, Mauro. > > Thierry