Em Tue, 28 Apr 2020 14:50:35 +0200
Neil Armstrong <narmstrong@xxxxxxxxxxxx> escreveu:
> From: Maxime Jourdan <mjourdan@xxxxxxxxxxxx>
>
> - Redo the logic where VP9 gets fresh CAPTURE buffers. The previous code
> could lead to a hardlock.
> - Reserve 4 margin buffers instead of 3, as apparently there are corner
> cases where 3 is not enough.
>
> Fixes: e9a3eb4819ca ("media: meson: vdec: add VP9 input support")
> Fixes: 00c43088aa68 ("media: meson: vdec: add VP9 decoder support")
> Signed-off-by: Maxime Jourdan <mjourdan@xxxxxxxxxxxx>
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> +static struct vb2_v4l2_buffer *get_free_vbuf(struct amvdec_session *sess)
> +{
> + struct codec_vp9 *vp9 = sess->priv;
> + struct vb2_v4l2_buffer *vbuf = v4l2_m2m_dst_buf_remove(sess->m2m_ctx);
> + struct vb2_v4l2_buffer *vbuf2;
> +
> + if (!vbuf)
> + return NULL;
> +
> + if (!codec_vp9_get_frame_by_idx(vp9, vbuf->vb2_buf.index))
> + return vbuf;
> +
> + vbuf2 = get_free_vbuf(sess);
Huh!!!!
Never use recursive functions inside the Kernel! Kernel stack is too
limited.
Also, even if Kernel stack would be unlimited, the above logic
would endlessly be calling get_free_vbuf(sess).
Thanks,
Mauro
