From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-lb0-f173.google.com ([209.85.217.173]:33015 "EHLO mail-lb0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752121AbcDUJP0 (ORCPT ); Thu, 21 Apr 2016 05:15:26 -0400 From: Ricardo Ribalda Delgado To: Pawel Osciak , Marek Szyprowski , Kyungmin Park , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ricardo Ribalda Delgado , Junghak Sung , stable@vger.kernel.org Subject: [PATCH] media: vb2: Fix regression on poll() for RW mode Date: Thu, 21 Apr 2016 11:15:16 +0200 Message-Id: <1461230116-6909-1-git-send-email-ricardo.ribalda@gmail.com> Sender: linux-media-owner@vger.kernel.org List-ID: When using a device is read/write mode, vb2 does not handle properly the first select/poll operation. It allways return POLLERR. The reason for this is that when this code has been refactored, some of the operations have changed their order, and now fileio emulator is not started by poll, due to a previous check. Reported-by: Dimitrios Katsaros Cc: Junghak Sung Cc: stable@vger.kernel.org Fixes: 49d8ab9feaf2 ("media] media: videobuf2: Separate vb2_poll()") Signed-off-by: Ricardo Ribalda Delgado --- drivers/media/v4l2-core/videobuf2-core.c | 8 ++++++++ drivers/media/v4l2-core/videobuf2-v4l2.c | 8 -------- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index 5d016f496e0e..199c65dbe330 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -2298,6 +2298,14 @@ unsigned int vb2_core_poll(struct vb2_queue *q, struct file *file, return POLLERR; /* + * For compatibility with vb1: if QBUF hasn't been called yet, then + * return POLLERR as well. This only affects capture queues, output + * queues will always initialize waiting_for_buffers to false. + */ + if (q->waiting_for_buffers && (req_events & (POLLIN | POLLRDNORM))) + return POLLERR; + + /* * For output streams you can call write() as long as there are fewer * buffers queued than there are buffers available. */ diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c index 91f552124050..c9bad9ef2104 100644 --- a/drivers/media/v4l2-core/videobuf2-v4l2.c +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c @@ -818,14 +818,6 @@ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait) poll_wait(file, &fh->wait, wait); } - /* - * For compatibility with vb1: if QBUF hasn't been called yet, then - * return POLLERR as well. This only affects capture queues, output - * queues will always initialize waiting_for_buffers to false. - */ - if (q->waiting_for_buffers && (req_events & (POLLIN | POLLRDNORM))) - return POLLERR; - return res | vb2_core_poll(q, file, wait); } EXPORT_SYMBOL_GPL(vb2_poll); -- 2.8.0.rc3