Hi Hans, On 05/14/14 12:39, Hans Verkuil wrote: > On 05/14/2014 08:29 AM, Arun Kumar K wrote: >> MFCv6 encoder needs specific minimum number of buffers to >> be queued in the CAPTURE plane. This minimum number will >> be known only when the sequence header is generated. >> So we used to allow STREAMON on the CAPTURE plane only after >> sequence header is generated and checked with the minimum >> buffer requirement. >> >> But this causes a problem that we call a vb2_buffer_done >> for the sequence header buffer before doing a STREAON on the >> CAPTURE plane. > > How could this ever have worked? Buffers aren't queued to the driver until > STREAMON is called, and calling vb2_buffer_done for a buffer that is not queued > first to the driver will mess up internal data (q->queued_count for one). > This worked till now because __enqueue_in_driver is called first and then start_streaming qop is called. In MFCv6, the start_streaming driver callback used to wait till sequence header interrupt is received and it used to do vb2_buffer_done in that interrupt context. So it happened after buffers are enqueued in driver and before completing the vb2_streamon. >> This used to still work fine until this patch >> was merged - >> b3379c6 : vb2: only call start_streaming if sufficient buffers are queued > > Are you testing with CONFIG_VIDEO_ADV_DEBUG set? If not, you should do so. That > will check whether all the vb2 calls are balanced. > > BTW, that's a small typo in s5p_mfc_enc.c (search for 'inavlid'). > I got it. Will post a patch fixing them. Thanks for spotting this. >> This problem should also come in earlier MFC firmware versions >> if the application calls STREAMON on CAPTURE with some delay >> after doing STREAMON on OUTPUT. > > You can also play around with the min_buffers_needed field. My rule-of-thumb is that > when start_streaming is called everything should be ready to stream. It is painful > for drivers to have to keep track of the 'do I have enough buffers' status. > > For that reason I introduced the min_buffers_needed field. What I believe you can > do here is to set it initially to a large value, preventing start_streaming from > being called, and once you really know the minimum number of buffers that you need > it can be updated again to the actual value. If a large value is kept in min_buffers_needed, there will be some unnecessary memory initialization needed for say 16 full HD raw YUV buffers when actual needed is only 4. And once the encoding is started, updating the min_buffers_needed to actual value doesnt give any advantage as nobody checks for it after that. So the whole idea is to not enforce a worst case buffer allocation requirement beforehand itself. I hope the current scheme of things works well for the requirement. Regards Arun > > I don't know this driver well enough to tell whether that works here or not, but > it is worth looking at IMHO. > > Regards, > > Hans > >> So this patch keeps the header buffer until the other frame >> buffers are ready and dequeues it just before the first frame >> is ready. >> >> Signed-off-by: Arun Kumar K <arun.kk@xxxxxxxxxxx> >> --- >> Changes from v1 >> - Addressed review comments from Sachin >> https://patchwork.linuxtv.org/patch/23839/ >> --- >> drivers/media/platform/s5p-mfc/s5p_mfc_common.h | 2 ++ >> drivers/media/platform/s5p-mfc/s5p_mfc_enc.c | 6 +++++- >> 2 files changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_common.h b/drivers/media/platform/s5p-mfc/s5p_mfc_common.h >> index f5404a6..cc2b96e 100644 >> --- a/drivers/media/platform/s5p-mfc/s5p_mfc_common.h >> +++ b/drivers/media/platform/s5p-mfc/s5p_mfc_common.h >> @@ -523,6 +523,7 @@ struct s5p_mfc_codec_ops { >> * @output_state: state of the output buffers queue >> * @src_bufs: information on allocated source buffers >> * @dst_bufs: information on allocated destination buffers >> + * @header_mb: buffer pointer of the encoded sequence header >> * @sequence: counter for the sequence number for v4l2 >> * @dec_dst_flag: flags for buffers queued in the hardware >> * @dec_src_buf_size: size of the buffer for source buffers in decoding >> @@ -607,6 +608,7 @@ struct s5p_mfc_ctx { >> int src_bufs_cnt; >> struct s5p_mfc_buf dst_bufs[MFC_MAX_BUFFERS]; >> int dst_bufs_cnt; >> + struct s5p_mfc_buf *header_mb; >> >> unsigned int sequence; >> unsigned long dec_dst_flag; >> diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c b/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c >> index f8c7053..0c8d593e 100644 >> --- a/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c >> +++ b/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c >> @@ -787,7 +787,7 @@ static int enc_post_seq_start(struct s5p_mfc_ctx *ctx) >> ctx->dst_queue_cnt--; >> vb2_set_plane_payload(dst_mb->b, 0, >> s5p_mfc_hw_call(dev->mfc_ops, get_enc_strm_size, dev)); >> - vb2_buffer_done(dst_mb->b, VB2_BUF_STATE_DONE); >> + ctx->header_mb = dst_mb; >> spin_unlock_irqrestore(&dev->irqlock, flags); >> } >> >> @@ -845,6 +845,10 @@ static int enc_post_frame_start(struct s5p_mfc_ctx *ctx) >> unsigned int strm_size; >> unsigned long flags; >> >> + if (ctx->header_mb) { >> + vb2_buffer_done(ctx->header_mb->b, VB2_BUF_STATE_DONE); >> + ctx->header_mb = NULL; >> + } >> slice_type = s5p_mfc_hw_call(dev->mfc_ops, get_enc_slice_type, dev); >> strm_size = s5p_mfc_hw_call(dev->mfc_ops, get_enc_strm_size, dev); >> mfc_debug(2, "Encoded slice type: %d\n", slice_type); >> > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
