From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from lists.s-osg.org ([54.187.51.154]:36521 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755203AbaIRKGY (ORCPT ); Thu, 18 Sep 2014 06:06:24 -0400 Date: Thu, 18 Sep 2014 07:06:19 -0300 From: Mauro Carvalho Chehab To: Linux Media Mailing List Cc: Mauro Carvalho Chehab , Laurent Pinchart , Hans Verkuil , Pawel Osciak , Nicolas Dufresne Subject: [PATCH v2] [media] BZ#84401: Revert "[media] v4l: vb2: Don't return POLLERR during transient buffer underruns" Message-ID: <20140918070619.32d4e4b1@recife.lan> In-Reply-To: <1410826255-2025-1-git-send-email-m.chehab@samsung.com> References: <1410826255-2025-1-git-send-email-m.chehab@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: This reverts commit 9241650d62f79a3da01f1d5e8ebd195083330b75. The commit 9241650d62f7 was meant to solve a race issue that affects Gstreamer version 0.10, when streaming for a long time. It does that by returning POLERR if VB2 is not streaming. However, it broke VBI userspace support on alevt and mtt (and maybe other VBI apps), as they rely on the old behavior. Due to that, we need to roll back and restore the previous behavior. For more details, see: https://bugzilla.kernel.org/show_bug.cgi?id=84401 So, let's rollback the change for now, and work on some other fix for it. Cc: Laurent Pinchart Cc: Hans Verkuil Cc: Pawel Osciak Cc: Nicolas Dufresne Signed-off-by: Mauro Carvalho Chehab -- v2: Just changed the description. This is a regression that broke a core feature with most (all) VBI apps. We should hurry sending a fix for it. So, let's just revert the patch while we're discussing/testing a solution that would solve Laurent's usecase scenario without breaking VBI. PS.: this patch should, of course, be c/c to 3.16 too, but I think we'll need to do a manual backport, as the check for q->error is likely newer than 3.16. diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index 7e6aff673a5a..da2d0adcc992 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -2583,10 +2583,10 @@ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait) } /* - * There is nothing to wait for if no buffer has been queued and the - * queue isn't streaming, or if the error flag is set. + * There is nothing to wait for if no buffer has been queued + * or if the error flag is set. */ - if ((list_empty(&q->queued_list) && !vb2_is_streaming(q)) || q->error) + if (list_empty(&q->queued_list) || q->error) return res | POLLERR; /*