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Message-id: <ae33ff08-0766-973e-3181-98fb01a76b9e@samsung.com> Date: Tue, 24 May 2016 12:21:17 +0200 From: Marek Szyprowski <m.szyprowski@...sung.com> To: Javier Martinez Canillas <javier@....samsung.com>, linux-kernel@...r.kernel.org Cc: Nicolas Dufresne <nicolas.dufresne@...labora.com>, ayaka <ayaka@...lik.info>, Shuah Khan <shuahkh@....samsung.com>, Mauro Carvalho Chehab <mchehab@....samsung.com>, Kamil Debski <k.debski@...sung.com>, Jeongtae Park <jtp.park@...sung.com>, Kyungmin Park <kyungmin.park@...sung.com>, linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org Subject: Re: [RESEND PATCH] [media] s5p-mfc: don't close instance after free OUTPUT buffers Hello, On 2016-05-07 00:11, Javier Martinez Canillas wrote: > From: ayaka <ayaka@...lik.info> > > User-space applications can use the VIDIOC_REQBUFS ioctl to determine if a > memory mapped, user pointer or DMABUF based I/O is supported by the driver. > > So a set of VIDIOC_REQBUFS ioctl calls will be made with count 0 and then > the real VIDIOC_REQBUFS call with count == n. But for count 0, the driver > not only frees the buffer but also closes the MFC instance and s5p_mfc_ctx > state is set to MFCINST_FREE. > > The VIDIOC_REQBUFS handler for the output device checks if the s5p_mfc_ctx > state is set to MFCINST_INIT (which happens on an VIDIOC_S_FMT) and fails > otherwise. So after a VIDIOC_REQBUFS(n), future VIDIOC_REQBUFS(n) calls > will fails unless a VIDIOC_S_FMT ioctl calls happens before the reqbufs. > > But applications may first set the format and then attempt to determine > the I/O methods supported by the driver (for example Gstramer does it) so > the state won't be set to MFCINST_INIT again and VIDIOC_REQBUFS will fail. > > To avoid this issue, only free the buffers on VIDIOC_REQBUFS(0) but don't > close the MFC instance to allow future VIDIOC_REQBUFS(n) calls to succeed. > > Signed-off-by: ayaka <ayaka@...lik.info> > [javier: Rewrote changelog to explain the problem more detailed] > Signed-off-by: Javier Martinez Canillas <javier@....samsung.com> Tested-by: Marek Szyprowski <m.szyprowski@...sung.com> > > --- > Hello, > > This is a resend of a patch posted by Ayaka some time ago [0]. > Without $SUBJECT, trying to decode a video using Gstramer fails > on an Exynos5422 Odroid XU4 board with following error message: > > $ gst-launch-1.0 filesrc location=test.mov ! qtdemux ! h264parse ! v4l2video0dec ! videoconvert ! autovideosink > > Setting pipeline to PAUSED ... > Pipeline is PREROLLING ... > [ 3947.114756] vidioc_reqbufs:576: Only V4L2_MEMORY_MAP is supported > [ 3947.114771] vidioc_reqbufs:576: Only V4L2_MEMORY_MAP is supported > [ 3947.114903] reqbufs_output:484: Reqbufs called in an invalid state > [ 3947.114913] reqbufs_output:510: Failed allocating buffers for OUTPUT queue > ERROR: from element /GstPipeline:pipeline0/v4l2video0dec:v4l2video0dec0: Failed to allocate required memory. > Additional debug info: > gstv4l2videodec.c(575): gst_v4l2_video_dec_handle_frame (): /GstPipeline:pipeline0/v4l2video0dec:v4l2video0dec0: > Buffer pool activation failed > ERROR: pipeline doesn't want to preroll. > Setting pipeline to NULL ... > Freeing pipeline ... > > [0]: https://patchwork.linuxtv.org/patch/32794/ > > Best regards, > Javier > > drivers/media/platform/s5p-mfc/s5p_mfc_dec.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c > index f2d6376ce618..8b9467de2d6a 100644 > --- a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c > +++ b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c > @@ -474,7 +474,6 @@ static int reqbufs_output(struct s5p_mfc_dev *dev, struct s5p_mfc_ctx *ctx, > ret = vb2_reqbufs(&ctx->vq_src, reqbufs); > if (ret) > goto out; > - s5p_mfc_close_mfc_inst(dev, ctx); > ctx->src_bufs_cnt = 0; > ctx->output_state = QUEUE_FREE; > } else if (ctx->output_state == QUEUE_FREE) { Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
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