V4L/DVB (8648): ivtv: improve CC support

- change the work-queue to a single threaded high prio workqueue
- use DMA instead of PIO for the sliced VBI data.
- remove some incorrect tests
- increase the internal VBI capture queue size for sliced VBI packets
- ignore duplicate VBI lines

With these changes it should finally be possible to get reliable closed
captions.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 8 insertions, 21 deletions

diff --git a/drivers/media/video/ivtv/ivtv-irq.c b/drivers/media/video/ivtv/ivtv-irq.c
index fba150a6cd23..34f3ab827858 100644
--- a/drivers/media/video/ivtv/ivtv-irq.c
+++ b/drivers/media/video/ivtv/ivtv-irq.c
@@ -76,6 +76,13 @@ void ivtv_irq_work_handler(struct work_struct *work)
 
         DEFINE_WAIT(wait);
 
+        if (test_and_clear_bit(IVTV_F_I_WORK_INITED, &itv->i_flags)) {
+                struct sched_param param = { .sched_priority = 99 };
+
+                /* This thread must use the FIFO scheduler as it
+                   is realtime sensitive. */
+                sched_setscheduler(current, SCHED_FIFO, &param);
+        }
         if (test_and_clear_bit(IVTV_F_I_WORK_HANDLER_PIO, &itv->i_flags))
                 ivtv_pio_work_handler(itv);
 
@@ -678,34 +685,14 @@ static void ivtv_irq_enc_start_cap(struct ivtv *itv)
 
 static void ivtv_irq_enc_vbi_cap(struct ivtv *itv)
 {
-        struct ivtv_stream *s_mpg = &itv->streams[IVTV_ENC_STREAM_TYPE_MPG];
         u32 data[CX2341X_MBOX_MAX_DATA];
         struct ivtv_stream *s;
 
         IVTV_DEBUG_HI_IRQ("ENC START VBI CAP\n");
         s = &itv->streams[IVTV_ENC_STREAM_TYPE_VBI];
 
-        /* If more than two VBI buffers are pending, then
-           clear the old ones and start with this new one.
-           This can happen during transition stages when MPEG capturing is
-           started, but the first interrupts haven't arrived yet. During
-           that period VBI requests can accumulate without being able to
-           DMA the data. Since at most four VBI DMA buffers are available,
-           we just drop the old requests when there are already three
-           requests queued. */
-        if (s->sg_pending_size > 2) {
-                struct ivtv_buffer *buf;
-                list_for_each_entry(buf, &s->q_predma.list, list)
-                        ivtv_buf_sync_for_cpu(s, buf);
-                ivtv_queue_move(s, &s->q_predma, NULL, &s->q_free, 0);
-                s->sg_pending_size = 0;
-        }
-        /* if we can append the data, and the MPEG stream isn't capturing,
-           then start a DMA request for just the VBI data. */
-        if (!stream_enc_dma_append(s, data) &&
-                        !test_bit(IVTV_F_S_STREAMING, &s_mpg->s_flags)) {
+        if (!stream_enc_dma_append(s, data))
                 set_bit(ivtv_use_pio(s) ? IVTV_F_S_PIO_PENDING : IVTV_F_S_DMA_PENDING, &s->s_flags);
-        }
 }
 
 static void ivtv_irq_dec_vbi_reinsert(struct ivtv *itv)