From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout3.w2.samsung.com ([211.189.100.13]:54039 "EHLO usmailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751697AbaIONzK convert rfc822-to-8bit (ORCPT ); Mon, 15 Sep 2014 09:55:10 -0400 Received: from uscpsbgm2.samsung.com (u115.gpu85.samsung.co.kr [203.254.195.115]) by usmailout3.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NBY00HER3ZX4D70@usmailout3.samsung.com> for linux-media@vger.kernel.org; Mon, 15 Sep 2014 09:55:09 -0400 (EDT) Date: Mon, 15 Sep 2014 10:55:03 -0300 From: Mauro Carvalho Chehab To: Nicolas Dufresne Cc: Laurent Pinchart , Hans Verkuil , Hans de Goede , linux-media@vger.kernel.org, Pawel Osciak , Marek Szyprowski , Kyungmin Park Subject: Re: [PATCH/RFC v2 1/2] v4l: vb2: Don't return POLLERR during transient buffer underruns Message-id: <20140915105503.105233bf.m.chehab@samsung.com> In-reply-to: <5416E208.5010302@collabora.com> References: <1401970991-4421-1-git-send-email-laurent.pinchart@ideasonboard.com> <5416CA2B.1080004@xs4all.nl> <20140915090224.5a2889a1.m.chehab@samsung.com> <11047185.EGVanoRbYV@avalon> <5416E208.5010302@collabora.com> MIME-version: 1.0 Content-type: text/plain; charset=UTF-8 Content-transfer-encoding: 8BIT Sender: linux-media-owner@vger.kernel.org List-ID: Em Mon, 15 Sep 2014 08:56:40 -0400 Nicolas Dufresne escreveu: > > Le 2014-09-15 08:49, Laurent Pinchart a écrit : > > Reverting the patch will also be a regression, as that would break > > applications that now rely on the new behaviour (I've developed this patch to > > fix a problem I've noticed with gstreamer). One way or another, we're screwed > > and we'll break userspace. Well, VB1 is working with the old behavior, as the breakage on saa7134 only happened after its migration to VB2. So, the Gstreamer version you tested is still very likely broken with VB1. So, I still think that the less damage is to revert the POLLERR patch, with, according to Hans, is also a violation at the documented API. > We have worked around this issue in GStreamer 1.4+, Good to know. > for older version, > the problem may be faced again by users, specially if using a newer > libv4l2 where the locking has been fixed (or no libv4l2). The DQBUF locking fixup was merged on libv4l2 for version 1.2. So, the potential breakage happens when libv4l2 is 1.2 and Gstreamer versions before 1.4. Do you have any procedure on gstreamer to fix a bug on stable releases? Those VBI applications don't have any, as they're not actively maintained anymore. Even if we patch them today, I guess it could take a long time for those changes to be propagated on distros. So, I guess that the best is to try to fix Gstreamer on the distros that are using libv4l version 1.2 and a pre-1.4 Gstreamer version. > > cheers, > Nicolas > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html