On Wed, 2019-09-04 at 10:01 -0300, Ezequiel Garcia wrote:
> On Wed, 2019-09-04 at 12:13 +0200, Philipp Zabel wrote:
> > Hi Ezequiel,
> >
> > On Tue, 2019-09-03 at 14:12 -0300, Ezequiel Garcia wrote:
> > > Commit 953aaa1492c53 ("media: rockchip/vpu: Prepare things to support decoders")
> > > changed the conditions under S_FMT was allowed for OUTPUT
> > > CAPTURE buffers.
> > >
> > > However, and according to the mem-to-mem stateless decoder specification,
> > > in order to support dynamic resolution changes, S_FMT should be allowed
> > > even if OUTPUT buffers have been allocated.
> > >
> > > Relax decoder S_FMT restrictions on OUTPUT buffers, allowing a resolution
> > > modification, provided the pixel format stays the same.
> > >
> > > Tested on RK3288 platforms using ChromiumOS Video Decode/Encode Accelerator Unittests.
> > >
> > > Fixes: 953aaa1492c53 ("media: rockchip/vpu: Prepare things to support decoders")
> > > Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
> > > ---
> > > drivers/staging/media/hantro/hantro_v4l2.c | 22 ++++++++++++++++------
> > > 1 file changed, 16 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/staging/media/hantro/hantro_v4l2.c b/drivers/staging/media/hantro/hantro_v4l2.c
> > > index 3dae52abb96c..d48b548842cf 100644
> > > --- a/drivers/staging/media/hantro/hantro_v4l2.c
> > > +++ b/drivers/staging/media/hantro/hantro_v4l2.c
> > > @@ -367,19 +367,22 @@ vidioc_s_fmt_out_mplane(struct file *file, void *priv, struct v4l2_format *f)
> > > {
> > > struct v4l2_pix_format_mplane *pix_mp = &f->fmt.pix_mp;
> > > struct hantro_ctx *ctx = fh_to_ctx(priv);
> > > + struct vb2_queue *vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
> > > const struct hantro_fmt *formats;
> > > unsigned int num_fmts;
> > > - struct vb2_queue *vq;
> > > int ret;
> > >
> > > - /* Change not allowed if queue is busy. */
> > > - vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
> > > - if (vb2_is_busy(vq))
> > > - return -EBUSY;
> > > -
> > > if (!hantro_is_encoder_ctx(ctx)) {
> > > struct vb2_queue *peer_vq;
> > >
> > > + /*
> > > + * In other to support dynamic resolution change,
> > > + * the decoder admits a resolution change, as long
> > > + * as the pixelformat remains. Can't be done if streaming.
> > > + */
> > > + if (vb2_is_streaming(vq) || (vb2_is_busy(vq) &&
> > > + pix_mp->pixelformat != ctx->src_fmt.pixelformat))
> >
> > Before using contents of the v4l2_format f for comparison, we should run
> > vidioc_try_fmt_out_mplane over it.
>
> Right, good catch.
>
> > Also, besides pixelformat, sizeimage
> > shouldn't change either, at least if this is a VB2_MMAP queue.
> >
>
> This is the OUTPUT queue, so I don't see why the sizeimage
> of the coded buffers should stay the same. Maybe I'm missing
> something?
If the OUTPUT vb2_queue is busy, we already have some buffers of the old
size allocated. We can't change their size dynamically with just
VIDIOC_S_FMT.
Maybe this should correct sizeimage to the old size instead of returning
-EBUSY? Either way, if the old buffer size is too small to reasonably
decode the new resolution, the OUTPUT buffers have to be reallocated.
regards
Philipp
