From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp-vbr1.xs4all.nl ([194.109.24.21]:2676 "EHLO smtp-vbr1.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751241AbaGWGBF (ORCPT ); Wed, 23 Jul 2014 02:01:05 -0400 Message-ID: <53CF4F94.9090905@xs4all.nl> Date: Wed, 23 Jul 2014 08:00:52 +0200 From: Hans Verkuil MIME-Version: 1.0 To: Scott Jiang , Hans Verkuil , Laurent Pinchart CC: linux-media@vger.kernel.org Subject: Re: [PATCH] v4l2: don't warn before we release buffer References: <1406174011-13600-1-git-send-email-scott.jiang.linux@gmail.com> In-Reply-To: <1406174011-13600-1-git-send-email-scott.jiang.linux@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 07/24/2014 05:53 AM, Scott Jiang wrote: > In fact we only need to give a warning if the driver still use the > buffer after we release all queued buffers. > > Signed-off-by: Scott Jiang Nacked-by: Hans Verkuil You're removing the warning telling you that your driver has a bug instead of fixing the driver bug itself. In stop_streaming the driver must hand over any buffers it owns to vb2 (vb2_buffer_done(..., STATE_ERROR)). If it doesn't you'll get this warning and vb2 will forcefully reclaim them, quite possibly leaving the driver with a corrupt buffer list. The same should occur in start_streaming if an error occurs. In that case start_streaming must return the buffers to STATE_DEQUEUED. So fix your driver instead :-) Regards, Hans > --- > drivers/media/v4l2-core/videobuf2-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c > index 7c4489c..fa5dd73 100644 > --- a/drivers/media/v4l2-core/videobuf2-core.c > +++ b/drivers/media/v4l2-core/videobuf2-core.c > @@ -2112,7 +2112,7 @@ static void __vb2_queue_cancel(struct vb2_queue *q) > if (q->start_streaming_called) > call_void_qop(q, stop_streaming, q); > > - if (WARN_ON(atomic_read(&q->owned_by_drv_count))) { > + if (atomic_read(&q->owned_by_drv_count)) { > for (i = 0; i < q->num_buffers; ++i) > if (q->bufs[i]->state == VB2_BUF_STATE_ACTIVE) > vb2_buffer_done(q->bufs[i], VB2_BUF_STATE_ERROR); >