Hi Chen-Yu,
Thanks for your suggestion.
On Tue, 2022-10-18 at 17:55 +0800, Chen-Yu Tsai wrote:
> On Mon, Oct 17, 2022 at 5:02 PM Yunfei Dong <yunfei.dong@xxxxxxxxxxxx
> > wrote:
> >
> > Some cavlc bistream will decode fail when the frame size is small
> > than
> > 20 bytes. Need to add pending data at the end of the bitstream.
>
> "magic terminating pattern" instead of "pending data"?
>
> > For the size of mapped memory is at least one page, adding four
> > bytes data
> > won't lead to access unknown virtual memory.
>
> Actually we can narrow this down a bit. The minimum dimension (16x16)
> sets the minimum size of the buffer at 256 bytes.
>
Fix in patch v2.
> > Fixes: 59fba9eed5a7 ("media: mediatek: vcodec: support stateless
> > H.264 decoding for mt8192")
> > Signed-off-by: Yunfei Dong <yunfei.dong@xxxxxxxxxxxx>
> > ---
> > .../vcodec/vdec/vdec_h264_req_multi_if.c | 27
> > ++++++++++++++++---
> > 1 file changed, 24 insertions(+), 3 deletions(-)
> >
> > diff --git
> > a/drivers/media/platform/mediatek/vcodec/vdec/vdec_h264_req_multi_i
> > f.c
> > b/drivers/media/platform/mediatek/vcodec/vdec/vdec_h264_req_multi_i
> > f.c
> > index 4cc92700692b..c1583dddcb04 100644
> > ---
> > a/drivers/media/platform/mediatek/vcodec/vdec/vdec_h264_req_multi_i
> > f.c
> > +++
> > b/drivers/media/platform/mediatek/vcodec/vdec/vdec_h264_req_multi_i
> > f.c
> > @@ -539,6 +539,24 @@ static int vdec_h264_slice_core_decode(struct
> > vdec_lat_buf *lat_buf)
> > return 0;
> > }
> >
> > +static void vdec_h264_insert_startcode(struct mtk_vcodec_dev
> > *vcodec_dev, unsigned char *buf,
> > + size_t *bs_size, struct
> > mtk_h264_pps_param *pps)
> > +{
> > + struct device *dev = &vcodec_dev->plat_dev->dev;
> > +
> > + /* cavlc bitstream when entropy_coding_mode_flag is false.
> > */
> > + if (pps->entropy_coding_mode_flag || *bs_size > 20 ||
> > + !(of_device_is_compatible(dev->of_node,
> > "mediatek,mt8192-vcodec-dec") ||
> > + of_device_is_compatible(dev->of_node, "mediatek,mt8195-
> > vcodec-dec")))
> > + return;
> > +
>
> There should be a comment here describing what is added.
>
Fix in patch v2.
>
> ChenYu
>
Best Regards,
Yunfei Dong
> > + buf[*bs_size] = 0;
> > + buf[*bs_size + 1] = 0;
> > + buf[*bs_size + 2] = 1;
> > + buf[*bs_size + 3] = 0xff;
> > + (*bs_size) += 4;
> > +}
> > +
> > static int vdec_h264_slice_lat_decode(void *h_vdec, struct
> > mtk_vcodec_mem *bs,
> > struct vdec_fb *fb, bool
> > *res_chg)
> > {
> > @@ -582,9 +600,6 @@ static int vdec_h264_slice_lat_decode(void
> > *h_vdec, struct mtk_vcodec_mem *bs,
> > }
> >
> > inst->vsi->dec.nal_info = buf[nal_start_idx];
> > - inst->vsi->dec.bs_buf_addr = (u64)bs->dma_addr;
> > - inst->vsi->dec.bs_buf_size = bs->size;
> > -
> > lat_buf->src_buf_req = src_buf_info-
> > >m2m_buf.vb.vb2_buf.req_obj.req;
> > v4l2_m2m_buf_copy_metadata(&src_buf_info->m2m_buf.vb,
> > &lat_buf->ts_info, true);
> >
> > @@ -592,6 +607,12 @@ static int vdec_h264_slice_lat_decode(void
> > *h_vdec, struct mtk_vcodec_mem *bs,
> > if (err)
> > goto err_free_fb_out;
> >
> > + vdec_h264_insert_startcode(inst->ctx->dev, buf, &bs->size,
> > + &share_info-
> > >h264_slice_params.pps);
> > +
> > + inst->vsi->dec.bs_buf_addr = (uint64_t)bs->dma_addr;
> > + inst->vsi->dec.bs_buf_size = bs->size;
> > +
> > *res_chg = inst->resolution_changed;
> > if (inst->resolution_changed) {
> > mtk_vcodec_debug(inst, "- resolution changed -");
> > --
> > 2.25.1
> >
