V4L/DVB (5675): Move big PIO accesses from the interrupt handler to a workhandler

Sliced VBI transfers use PIO instead of DMA. This was done inside the
interrupt handler, but since PIO accesses are very slow this meant that
a lot of time was spent inside the interrupt handler. All PIO copies are
now moved to a workqueue. This should fix various issues with missing time
ticks and remote key hits.

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

7 files changed, 209 insertions, 86 deletions

diff --git a/drivers/media/video/ivtv/ivtv-driver.c b/drivers/media/video/ivtv/ivtv-driver.c
index e29f949adf57..efc66355339a 100644
--- a/drivers/media/video/ivtv/ivtv-driver.c
+++ b/drivers/media/video/ivtv/ivtv-driver.c
@@ -652,6 +652,7 @@ static int __devinit ivtv_init_struct1(struct ivtv *itv)
         itv->dma_timer.data = (unsigned long)itv;
 
         itv->cur_dma_stream = -1;
+        itv->cur_pio_stream = -1;
         itv->audio_stereo_mode = AUDIO_STEREO;
         itv->audio_bilingual_mode = AUDIO_MONO_LEFT;
 
diff --git a/drivers/media/video/ivtv/ivtv-driver.h b/drivers/media/video/ivtv/ivtv-driver.h
index 552f04511ead..e6e56f175f3f 100644
--- a/drivers/media/video/ivtv/ivtv-driver.h
+++ b/drivers/media/video/ivtv/ivtv-driver.h
@@ -237,6 +237,7 @@ extern const u32 yuv_offset[4];
 #define IVTV_IRQ_ENC_VBI_CAP            (0x1 << 29)
 #define IVTV_IRQ_ENC_VIM_RST            (0x1 << 28)
 #define IVTV_IRQ_ENC_DMA_COMPLETE       (0x1 << 27)
+#define IVTV_IRQ_ENC_PIO_COMPLETE       (0x1 << 25)
 #define IVTV_IRQ_DEC_AUD_MODE_CHG       (0x1 << 24)
 #define IVTV_IRQ_DEC_DATA_REQ           (0x1 << 22)
 #define IVTV_IRQ_DEC_DMA_COMPLETE       (0x1 << 20)
@@ -247,7 +248,8 @@ extern const u32 yuv_offset[4];
 #define IVTV_IRQ_DEC_VSYNC              (0x1 << 10)
 
 /* IRQ Masks */
-#define IVTV_IRQ_MASK_INIT (IVTV_IRQ_DMA_ERR|IVTV_IRQ_ENC_DMA_COMPLETE|IVTV_IRQ_DMA_READ)
+#define IVTV_IRQ_MASK_INIT (IVTV_IRQ_DMA_ERR|IVTV_IRQ_ENC_DMA_COMPLETE|\
+                IVTV_IRQ_DMA_READ|IVTV_IRQ_ENC_PIO_COMPLETE)
 
 #define IVTV_IRQ_MASK_CAPTURE (IVTV_IRQ_ENC_START_CAP | IVTV_IRQ_ENC_EOS)
 #define IVTV_IRQ_MASK_DECODE  (IVTV_IRQ_DEC_DATA_REQ|IVTV_IRQ_DEC_AUD_MODE_CHG)
@@ -374,6 +376,9 @@ struct ivtv_mailbox_data {
 #define IVTV_F_S_STREAMOFF      7       /* signal end of stream EOS */
 #define IVTV_F_S_APPL_IO        8       /* this stream is used read/written by an application */
 
+#define IVTV_F_S_PIO_PENDING    9       /* this stream has pending PIO */
+#define IVTV_F_S_PIO_HAS_VBI    1       /* the current PIO request also requests VBI data */
+
 /* per-ivtv, i_flags */
 #define IVTV_F_I_DMA               0    /* DMA in progress */
 #define IVTV_F_I_UDMA              1    /* UDMA in progress */
@@ -390,8 +395,11 @@ struct ivtv_mailbox_data {
 #define IVTV_F_I_DECODING_YUV      12   /* this stream is YUV frame decoding */
 #define IVTV_F_I_ENC_PAUSED        13   /* the encoder is paused */
 #define IVTV_F_I_VALID_DEC_TIMINGS 14   /* last_dec_timing is valid */
-#define IVTV_F_I_WORK_HANDLER_VBI  15   /* there is work to be done for VBI */
-#define IVTV_F_I_WORK_HANDLER_YUV  16   /* there is work to be done for YUV */
+#define IVTV_F_I_HAVE_WORK         15   /* Used in the interrupt handler: there is work to be done */
+#define IVTV_F_I_WORK_HANDLER_VBI  16   /* there is work to be done for VBI */
+#define IVTV_F_I_WORK_HANDLER_YUV  17   /* there is work to be done for YUV */
+#define IVTV_F_I_WORK_HANDLER_PIO  18   /* there is work to be done for PIO */
+#define IVTV_F_I_PIO               19   /* PIO in progress */
 
 /* Event notifications */
 #define IVTV_F_I_EV_DEC_STOPPED    28   /* decoder stopped event */
@@ -484,6 +492,7 @@ struct ivtv_stream {
 
         /* Base Dev SG Array for cx23415/6 */
         struct ivtv_SG_element *SGarray;
+        struct ivtv_SG_element *PIOarray;
         dma_addr_t SG_handle;
         int SG_length;
 
@@ -706,6 +715,7 @@ struct ivtv {
         atomic_t decoding;      /* count number of active decoding streams */
         u32 irq_rr_idx; /* Round-robin stream index */
         int cur_dma_stream;     /* index of stream doing DMA */
+        int cur_pio_stream;     /* index of stream doing PIO */
         u32 dma_data_req_offset;
         u32 dma_data_req_size;
         int output_mode;        /* NONE, MPG, YUV, UDMA YUV, passthrough */
diff --git a/drivers/media/video/ivtv/ivtv-irq.c b/drivers/media/video/ivtv/ivtv-irq.c
index c3a047b381b3..ba98bf054f2e 100644
--- a/drivers/media/video/ivtv/ivtv-irq.c
+++ b/drivers/media/video/ivtv/ivtv-irq.c
@@ -31,8 +31,6 @@
 
 #define DMA_MAGIC_COOKIE 0x000001fe
 
-#define SLICED_VBI_PIO 1
-
 static void ivtv_dma_dec_start(struct ivtv_stream *s);
 
 static const int ivtv_stream_map[] = {
@@ -42,12 +40,40 @@ static const int ivtv_stream_map[] = {
         IVTV_ENC_STREAM_TYPE_VBI,
 };
 
-static inline int ivtv_use_pio(struct ivtv_stream *s)
+
+static void ivtv_pio_work_handler(struct ivtv *itv)
 {
-        struct ivtv *itv = s->itv;
+        struct ivtv_stream *s = &itv->streams[itv->cur_pio_stream];
+        struct ivtv_buffer *buf;
+        struct list_head *p;
+        int i = 0;
+
+        IVTV_DEBUG_DMA("ivtv_pio_work_handler\n");
+        if (itv->cur_pio_stream < 0 || itv->cur_pio_stream >= IVTV_MAX_STREAMS ||
+                        s->v4l2dev == NULL || !ivtv_use_pio(s)) {
+                itv->cur_pio_stream = -1;
+                /* trigger PIO complete user interrupt */
+                write_reg(IVTV_IRQ_ENC_PIO_COMPLETE, 0x44);
+                return;
+        }
+        IVTV_DEBUG_DMA("Process PIO %s\n", s->name);
+        buf = list_entry(s->q_dma.list.next, struct ivtv_buffer, list);
+        list_for_each(p, &s->q_dma.list) {
+                struct ivtv_buffer *buf = list_entry(p, struct ivtv_buffer, list);
+                u32 size = s->PIOarray[i].size & 0x3ffff;
 
-        return s->dma == PCI_DMA_NONE ||
-            (SLICED_VBI_PIO && s->type == IVTV_ENC_STREAM_TYPE_VBI && itv->vbi.sliced_in->service_set);
+                /* Copy the data from the card to the buffer */
+                if (s->type == IVTV_DEC_STREAM_TYPE_VBI) {
+                        memcpy_fromio(buf->buf, itv->dec_mem + s->PIOarray[i].src - IVTV_DECODER_OFFSET, size);
+                }
+                else {
+                        memcpy_fromio(buf->buf, itv->enc_mem + s->PIOarray[i].src, size);
+                }
+                if (s->PIOarray[i].size & 0x80000000)
+                        break;
+                i++;
+        }
+        write_reg(IVTV_IRQ_ENC_PIO_COMPLETE, 0x44);
 }
 
 void ivtv_irq_work_handler(struct work_struct *work)
@@ -56,8 +82,11 @@ void ivtv_irq_work_handler(struct work_struct *work)
 
         DEFINE_WAIT(wait);
 
+        if (test_and_clear_bit(IVTV_F_I_WORK_HANDLER_PIO, &itv->i_flags))
+                ivtv_pio_work_handler(itv);
+
         if (test_and_clear_bit(IVTV_F_I_WORK_HANDLER_VBI, &itv->i_flags))
-                vbi_work_handler(itv);
+                ivtv_vbi_work_handler(itv);
 
         if (test_and_clear_bit(IVTV_F_I_WORK_HANDLER_YUV, &itv->i_flags))
                 ivtv_yuv_work_handler(itv);
@@ -173,8 +202,7 @@ static int stream_enc_dma_append(struct ivtv_stream *s, u32 data[CX2341X_MBOX_MA
         }
         s->buffers_stolen = rc;
 
-        /* got the buffers, now fill in SGarray (DMA) or copy the data from the card
-           to the buffers (PIO). */
+        /* got the buffers, now fill in SGarray (DMA) */
         buf = list_entry(s->q_predma.list.next, struct ivtv_buffer, list);
         memset(buf->buf, 0, 128);
         list_for_each(p, &s->q_predma.list) {
@@ -182,21 +210,11 @@ static int stream_enc_dma_append(struct ivtv_stream *s, u32 data[CX2341X_MBOX_MA
 
                 if (skip_bufs-- > 0)
                         continue;
-                if (!ivtv_use_pio(s)) {
-                        s->SGarray[idx].dst = cpu_to_le32(buf->dma_handle);
-                        s->SGarray[idx].src = cpu_to_le32(offset);
-                        s->SGarray[idx].size = cpu_to_le32(s->buf_size);
-                }
+                s->SGarray[idx].dst = cpu_to_le32(buf->dma_handle);
+                s->SGarray[idx].src = cpu_to_le32(offset);
+                s->SGarray[idx].size = cpu_to_le32(s->buf_size);
                 buf->bytesused = (size < s->buf_size) ? size : s->buf_size;
 
-                /* If PIO, then copy the data from the card to the buffer */
-                if (s->type == IVTV_DEC_STREAM_TYPE_VBI) {
-                        memcpy_fromio(buf->buf, itv->dec_mem + offset - IVTV_DECODER_OFFSET, buf->bytesused);
-                }
-                else if (ivtv_use_pio(s)) {
-                        memcpy_fromio(buf->buf, itv->enc_mem + offset, buf->bytesused);
-                }
-
                 s->q_predma.bytesused += buf->bytesused;
                 size -= buf->bytesused;
                 offset += s->buf_size;
@@ -224,11 +242,6 @@ static void dma_post(struct ivtv_stream *s)
         u32 *u32buf;
         int x = 0;
 
-        if (ivtv_use_pio(s)) {
-                if (s->q_predma.bytesused)
-                        ivtv_queue_move(s, &s->q_predma, NULL, &s->q_dma, s->q_predma.bytesused);
-                s->SG_length = 0;
-        }
         IVTV_DEBUG_DMA("%s %s completed (%x)\n", ivtv_use_pio(s) ? "PIO" : "DMA",
                         s->name, s->dma_offset);
         list_for_each(p, &s->q_dma.list) {
@@ -278,10 +291,14 @@ static void dma_post(struct ivtv_stream *s)
         if (buf)
                 buf->bytesused += s->dma_last_offset;
         if (buf && s->type == IVTV_DEC_STREAM_TYPE_VBI) {
-                /* Parse and Groom VBI Data */
-                s->q_dma.bytesused -= buf->bytesused;
-                ivtv_process_vbi_data(itv, buf, 0, s->type);
-                s->q_dma.bytesused += buf->bytesused;
+                list_for_each(p, &s->q_dma.list) {
+                        buf = list_entry(p, struct ivtv_buffer, list);
+
+                        /* Parse and Groom VBI Data */
+                        s->q_dma.bytesused -= buf->bytesused;
+                        ivtv_process_vbi_data(itv, buf, 0, s->type);
+                        s->q_dma.bytesused += buf->bytesused;
+                }
                 if (s->id == -1) {
                         ivtv_queue_move(s, &s->q_dma, NULL, &s->q_free, 0);
                         return;
@@ -351,10 +368,14 @@ static void ivtv_dma_enc_start(struct ivtv_stream *s)
         struct ivtv_stream *s_vbi = &itv->streams[IVTV_ENC_STREAM_TYPE_VBI];
         int i;
 
+        IVTV_DEBUG_DMA("start %s for %s\n", ivtv_use_dma(s) ? "DMA" : "PIO", s->name);
+
         if (s->q_predma.bytesused)
                 ivtv_queue_move(s, &s->q_predma, NULL, &s->q_dma, s->q_predma.bytesused);
-        IVTV_DEBUG_DMA("start DMA for %s\n", s->name);
-        s->SGarray[s->SG_length - 1].size = cpu_to_le32(le32_to_cpu(s->SGarray[s->SG_length - 1].size) + 256);
+
+        if (ivtv_use_dma(s))
+                s->SGarray[s->SG_length - 1].size =
+                        cpu_to_le32(le32_to_cpu(s->SGarray[s->SG_length - 1].size) + 256);
 
         /* If this is an MPEG stream, and VBI data is also pending, then append the
            VBI DMA to the MPEG DMA and transfer both sets of data at once.
@@ -368,7 +389,8 @@ static void ivtv_dma_enc_start(struct ivtv_stream *s)
         if (s->type == IVTV_ENC_STREAM_TYPE_MPG && s_vbi->SG_length &&
                         s->SG_length + s_vbi->SG_length <= s->buffers) {
                 ivtv_queue_move(s_vbi, &s_vbi->q_predma, NULL, &s_vbi->q_dma, s_vbi->q_predma.bytesused);
-                s_vbi->SGarray[s_vbi->SG_length - 1].size = cpu_to_le32(le32_to_cpu(s_vbi->SGarray[s->SG_length - 1].size) + 256);
+                if (ivtv_use_dma(s_vbi))
+                        s_vbi->SGarray[s_vbi->SG_length - 1].size = cpu_to_le32(le32_to_cpu(s_vbi->SGarray[s->SG_length - 1].size) + 256);
                 for (i = 0; i < s_vbi->SG_length; i++) {
                         s->SGarray[s->SG_length++] = s_vbi->SGarray[i];
                 }
@@ -381,14 +403,26 @@ static void ivtv_dma_enc_start(struct ivtv_stream *s)
         /* Mark last buffer size for Interrupt flag */
         s->SGarray[s->SG_length - 1].size |= cpu_to_le32(0x80000000);
 
-        /* Sync Hardware SG List of buffers */
-        ivtv_stream_sync_for_device(s);
-        write_reg(s->SG_handle, IVTV_REG_ENCDMAADDR);
-        write_reg_sync(read_reg(IVTV_REG_DMAXFER) | 0x02, IVTV_REG_DMAXFER);
-        set_bit(IVTV_F_I_DMA, &itv->i_flags);
-        itv->cur_dma_stream = s->type;
-        itv->dma_timer.expires = jiffies + HZ / 10;
-        add_timer(&itv->dma_timer);
+        if (ivtv_use_pio(s)) {
+                for (i = 0; i < s->SG_length; i++) {
+                        s->PIOarray[i].src = le32_to_cpu(s->SGarray[i].src);
+                        s->PIOarray[i].size = le32_to_cpu(s->SGarray[i].size);
+                }
+                set_bit(IVTV_F_I_WORK_HANDLER_PIO, &itv->i_flags);
+                set_bit(IVTV_F_I_HAVE_WORK, &itv->i_flags);
+                set_bit(IVTV_F_I_PIO, &itv->i_flags);
+                itv->cur_pio_stream = s->type;
+        }
+        else {
+                /* Sync Hardware SG List of buffers */
+                ivtv_stream_sync_for_device(s);
+                write_reg(s->SG_handle, IVTV_REG_ENCDMAADDR);
+                write_reg_sync(read_reg(IVTV_REG_DMAXFER) | 0x02, IVTV_REG_DMAXFER);
+                set_bit(IVTV_F_I_DMA, &itv->i_flags);
+                itv->cur_dma_stream = s->type;
+                itv->dma_timer.expires = jiffies + HZ / 10;
+                add_timer(&itv->dma_timer);
+        }
 }
 
 static void ivtv_dma_dec_start(struct ivtv_stream *s)
@@ -489,6 +523,40 @@ static void ivtv_irq_enc_dma_complete(struct ivtv *itv)
         wake_up(&itv->dma_waitq);
 }
 
+static void ivtv_irq_enc_pio_complete(struct ivtv *itv)
+{
+        struct ivtv_stream *s;
+
+        if (itv->cur_pio_stream < 0 || itv->cur_pio_stream >= IVTV_MAX_STREAMS) {
+                itv->cur_pio_stream = -1;
+                return;
+        }
+        s = &itv->streams[itv->cur_pio_stream];
+        IVTV_DEBUG_IRQ("ENC PIO COMPLETE %s\n", s->name);
+        s->SG_length = 0;
+        clear_bit(IVTV_F_I_ENC_VBI, &itv->i_flags);
+        clear_bit(IVTV_F_I_PIO, &itv->i_flags);
+        itv->cur_pio_stream = -1;
+        dma_post(s);
+        if (s->type == IVTV_ENC_STREAM_TYPE_MPG)
+                ivtv_vapi(itv, CX2341X_ENC_SCHED_DMA_TO_HOST, 3, 0, 0, 0);
+        else if (s->type == IVTV_ENC_STREAM_TYPE_YUV)
+                ivtv_vapi(itv, CX2341X_ENC_SCHED_DMA_TO_HOST, 3, 0, 0, 1);
+        else if (s->type == IVTV_ENC_STREAM_TYPE_PCM)
+                ivtv_vapi(itv, CX2341X_ENC_SCHED_DMA_TO_HOST, 3, 0, 0, 2);
+        clear_bit(IVTV_F_I_PIO, &itv->i_flags);
+        if (test_and_clear_bit(IVTV_F_S_DMA_HAS_VBI, &s->s_flags)) {
+                u32 tmp;
+
+                s = &itv->streams[IVTV_ENC_STREAM_TYPE_VBI];
+                tmp = s->dma_offset;
+                s->dma_offset = itv->vbi.dma_offset;
+                dma_post(s);
+                s->dma_offset = tmp;
+        }
+        wake_up(&itv->dma_waitq);
+}
+
 static void ivtv_irq_dma_err(struct ivtv *itv)
 {
         u32 data[CX2341X_MBOX_MAX_DATA];
@@ -532,13 +600,7 @@ static void ivtv_irq_enc_start_cap(struct ivtv *itv)
         clear_bit(IVTV_F_I_ENC_VBI, &itv->i_flags);
         s = &itv->streams[ivtv_stream_map[data[0]]];
         if (!stream_enc_dma_append(s, data)) {
-                if (ivtv_use_pio(s)) {
-                        dma_post(s);
-                        ivtv_vapi(itv, CX2341X_ENC_SCHED_DMA_TO_HOST, 3, 0, 0, data[0]);
-                }
-                else {
-                        set_bit(IVTV_F_S_DMA_PENDING, &s->s_flags);
-                }
+                set_bit(ivtv_use_pio(s) ? IVTV_F_S_PIO_PENDING : IVTV_F_S_DMA_PENDING, &s->s_flags);
         }
 }
 
@@ -551,15 +613,6 @@ static void ivtv_irq_enc_vbi_cap(struct ivtv *itv)
         IVTV_DEBUG_IRQ("ENC START VBI CAP\n");
         s = &itv->streams[IVTV_ENC_STREAM_TYPE_VBI];
 
-        if (ivtv_use_pio(s)) {
-                if (stream_enc_dma_append(s, data))
-                        return;
-                if (s->q_predma.bytesused)
-                        ivtv_queue_move(s, &s->q_predma, NULL, &s->q_dma, s->q_predma.bytesused);
-                s->SG_length = 0;
-                dma_post(s);
-                return;
-        }
         /* 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
@@ -582,11 +635,11 @@ static void ivtv_irq_enc_vbi_cap(struct ivtv *itv)
         if (!stream_enc_dma_append(s, data) &&
                         !test_bit(IVTV_F_S_STREAMING, &s_mpg->s_flags)) {
                 set_bit(IVTV_F_I_ENC_VBI, &itv->i_flags);
-                set_bit(IVTV_F_S_DMA_PENDING, &s->s_flags);
+                set_bit(ivtv_use_pio(s) ? IVTV_F_S_PIO_PENDING : IVTV_F_S_DMA_PENDING, &s->s_flags);
         }
 }
 
-static void ivtv_irq_dev_vbi_reinsert(struct ivtv *itv)
+static void ivtv_irq_dec_vbi_reinsert(struct ivtv *itv)
 {
         u32 data[CX2341X_MBOX_MAX_DATA];
         struct ivtv_stream *s = &itv->streams[IVTV_DEC_STREAM_TYPE_VBI];
@@ -594,7 +647,7 @@ static void ivtv_irq_dev_vbi_reinsert(struct ivtv *itv)
         IVTV_DEBUG_IRQ("DEC VBI REINSERT\n");
         if (test_bit(IVTV_F_S_CLAIMED, &s->s_flags) &&
                         !stream_enc_dma_append(s, data)) {
-                dma_post(s);
+                set_bit(IVTV_F_S_PIO_PENDING, &s->s_flags);
         }
 }
 
@@ -657,7 +710,6 @@ static void ivtv_irq_vsync(struct ivtv *itv)
         }
         if (frame != (itv->lastVsyncFrame & 1)) {
                 struct ivtv_stream *s = ivtv_get_output_stream(itv);
-                int work = 0;
 
                 itv->lastVsyncFrame += 1;
                 if (frame == 0) {
@@ -678,7 +730,7 @@ static void ivtv_irq_vsync(struct ivtv *itv)
                 /* Send VBI to saa7127 */
                 if (frame) {
                         set_bit(IVTV_F_I_WORK_HANDLER_VBI, &itv->i_flags);
-                        work = 1;
+                        set_bit(IVTV_F_I_HAVE_WORK, &itv->i_flags);
                 }
 
                 /* Check if we need to update the yuv registers */
@@ -691,11 +743,9 @@ static void ivtv_irq_vsync(struct ivtv *itv)
                                 itv->yuv_info.new_frame_info[last_dma_frame].update = 0;
                                 itv->yuv_info.yuv_forced_update = 0;
                                 set_bit(IVTV_F_I_WORK_HANDLER_YUV, &itv->i_flags);
-                                work = 1;
+                                set_bit(IVTV_F_I_HAVE_WORK, &itv->i_flags);
                         }
                 }
-                if (work)
-                        queue_work(itv->irq_work_queues, &itv->irq_work_queue);
         }
 }
 
@@ -755,6 +805,10 @@ irqreturn_t ivtv_irq_handler(int irq, void *dev_id)
                 ivtv_irq_enc_dma_complete(itv);
         }
 
+        if (combo & IVTV_IRQ_ENC_PIO_COMPLETE) {
+                ivtv_irq_enc_pio_complete(itv);
+        }
+
         if (combo & IVTV_IRQ_DMA_ERR) {
                 ivtv_irq_dma_err(itv);
         }
@@ -768,7 +822,7 @@ irqreturn_t ivtv_irq_handler(int irq, void *dev_id)
         }
 
         if (combo & IVTV_IRQ_DEC_VBI_RE_INSERT) {
-                ivtv_irq_dev_vbi_reinsert(itv);
+                ivtv_irq_dec_vbi_reinsert(itv);
         }
 
         if (combo & IVTV_IRQ_ENC_EOS) {
@@ -813,6 +867,22 @@ irqreturn_t ivtv_irq_handler(int irq, void *dev_id)
                 }
         }
 
+        if ((combo & IVTV_IRQ_DMA) && !test_bit(IVTV_F_I_PIO, &itv->i_flags)) {
+                for (i = 0; i < IVTV_MAX_STREAMS; i++) {
+                        int idx = (i + itv->irq_rr_idx++) % IVTV_MAX_STREAMS;
+                        struct ivtv_stream *s = &itv->streams[idx];
+
+                        if (!test_and_clear_bit(IVTV_F_S_PIO_PENDING, &s->s_flags))
+                                continue;
+                        if (s->type == IVTV_DEC_STREAM_TYPE_VBI || s->type < IVTV_DEC_STREAM_TYPE_MPG)
+                                ivtv_dma_enc_start(s);
+                        break;
+                }
+        }
+
+        if (test_and_clear_bit(IVTV_F_I_HAVE_WORK, &itv->i_flags))
+                queue_work(itv->irq_work_queues, &itv->irq_work_queue);
+
         spin_unlock(&itv->dma_reg_lock);
 
         /* If we've just handled a 'forced' vsync, it's safest to say it
diff --git a/drivers/media/video/ivtv/ivtv-queue.c b/drivers/media/video/ivtv/ivtv-queue.c
index ccfcef1ad91a..a04f9387f63d 100644
--- a/drivers/media/video/ivtv/ivtv-queue.c
+++ b/drivers/media/video/ivtv/ivtv-queue.c
@@ -195,14 +195,26 @@ int ivtv_stream_alloc(struct ivtv_stream *s)
                 s->dma != PCI_DMA_NONE ? "DMA " : "",
                 s->name, s->buffers, s->buf_size, s->buffers * s->buf_size / 1024);
 
-        /* Allocate DMA SG Arrays */
-        if (s->dma != PCI_DMA_NONE) {
-                s->SGarray = (struct ivtv_SG_element *)kzalloc(SGsize, GFP_KERNEL);
-                if (s->SGarray == NULL) {
-                        IVTV_ERR("Could not allocate SGarray for %s stream\n", s->name);
+        if (ivtv_might_use_pio(s)) {
+                s->PIOarray = (struct ivtv_SG_element *)kzalloc(SGsize, GFP_KERNEL);
+                if (s->PIOarray == NULL) {
+                        IVTV_ERR("Could not allocate PIOarray for %s stream\n", s->name);
                         return -ENOMEM;
                 }
-                s->SG_length = 0;
+        }
+
+        /* Allocate DMA SG Arrays */
+        s->SGarray = (struct ivtv_SG_element *)kzalloc(SGsize, GFP_KERNEL);
+        if (s->SGarray == NULL) {
+                IVTV_ERR("Could not allocate SGarray for %s stream\n", s->name);
+                if (ivtv_might_use_pio(s)) {
+                        kfree(s->PIOarray);
+                        s->PIOarray = NULL;
+                }
+                return -ENOMEM;
+        }
+        s->SG_length = 0;
+        if (ivtv_might_use_dma(s)) {
                 s->SG_handle = pci_map_single(itv->dev, s->SGarray, SGsize, s->dma);
                 ivtv_stream_sync_for_cpu(s);
         }
@@ -219,7 +231,7 @@ int ivtv_stream_alloc(struct ivtv_stream *s)
                         break;
                 }
                 INIT_LIST_HEAD(&buf->list);
-                if (s->dma != PCI_DMA_NONE) {
+                if (ivtv_might_use_dma(s)) {
                         buf->dma_handle = pci_map_single(s->itv->dev,
                                 buf->buf, s->buf_size + 256, s->dma);
                         ivtv_buf_sync_for_cpu(s, buf);
@@ -242,7 +254,7 @@ void ivtv_stream_free(struct ivtv_stream *s)
 
         /* empty q_free */
         while ((buf = ivtv_dequeue(s, &s->q_free))) {
-                if (s->dma != PCI_DMA_NONE)
+                if (ivtv_might_use_dma(s))
                         pci_unmap_single(s->itv->dev, buf->dma_handle,
                                 s->buf_size + 256, s->dma);
                 kfree(buf->buf);
@@ -256,6 +268,9 @@ void ivtv_stream_free(struct ivtv_stream *s)
                                  sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
                         s->SG_handle = IVTV_DMA_UNMAPPED;
                 }
+                kfree(s->SGarray);
+                kfree(s->PIOarray);
+                s->PIOarray = NULL;
                 s->SGarray = NULL;
                 s->SG_length = 0;
         }
diff --git a/drivers/media/video/ivtv/ivtv-queue.h b/drivers/media/video/ivtv/ivtv-queue.h
index 903edd4b4381..2ed8d548255d 100644
--- a/drivers/media/video/ivtv/ivtv-queue.h
+++ b/drivers/media/video/ivtv/ivtv-queue.h
@@ -20,18 +20,43 @@
  */
 
 #define IVTV_DMA_UNMAPPED       ((u32) -1)
+#define SLICED_VBI_PIO 1
 
 /* ivtv_buffer utility functions */
+
+static inline int ivtv_might_use_pio(struct ivtv_stream *s)
+{
+        return s->dma == PCI_DMA_NONE || (SLICED_VBI_PIO && s->type == IVTV_ENC_STREAM_TYPE_VBI);
+}
+
+static inline int ivtv_use_pio(struct ivtv_stream *s)
+{
+        struct ivtv *itv = s->itv;
+
+        return s->dma == PCI_DMA_NONE ||
+            (SLICED_VBI_PIO && s->type == IVTV_ENC_STREAM_TYPE_VBI && itv->vbi.sliced_in->service_set);
+}
+
+static inline int ivtv_might_use_dma(struct ivtv_stream *s)
+{
+        return s->dma != PCI_DMA_NONE;
+}
+
+static inline int ivtv_use_dma(struct ivtv_stream *s)
+{
+        return !ivtv_use_pio(s);
+}
+
 static inline void ivtv_buf_sync_for_cpu(struct ivtv_stream *s, struct ivtv_buffer *buf)
 {
-        if (s->dma != PCI_DMA_NONE)
+        if (ivtv_use_dma(s))
                 pci_dma_sync_single_for_cpu(s->itv->dev, buf->dma_handle,
                                 s->buf_size + 256, s->dma);
 }
 
 static inline void ivtv_buf_sync_for_device(struct ivtv_stream *s, struct ivtv_buffer *buf)
 {
-        if (s->dma != PCI_DMA_NONE)
+        if (ivtv_use_dma(s))
                 pci_dma_sync_single_for_device(s->itv->dev, buf->dma_handle,
                                 s->buf_size + 256, s->dma);
 }
@@ -53,12 +78,14 @@ void ivtv_stream_free(struct ivtv_stream *s);
 
 static inline void ivtv_stream_sync_for_cpu(struct ivtv_stream *s)
 {
-        pci_dma_sync_single_for_cpu(s->itv->dev, s->SG_handle,
-                sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
+        if (ivtv_use_dma(s))
+                pci_dma_sync_single_for_cpu(s->itv->dev, s->SG_handle,
+                        sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
 }
 
 static inline void ivtv_stream_sync_for_device(struct ivtv_stream *s)
 {
-        pci_dma_sync_single_for_device(s->itv->dev, s->SG_handle,
-                sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
+        if (ivtv_use_dma(s))
+                pci_dma_sync_single_for_device(s->itv->dev, s->SG_handle,
+                        sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
 }
diff --git a/drivers/media/video/ivtv/ivtv-vbi.c b/drivers/media/video/ivtv/ivtv-vbi.c
index 5efa5a867818..3ba46e07ea1f 100644
--- a/drivers/media/video/ivtv/ivtv-vbi.c
+++ b/drivers/media/video/ivtv/ivtv-vbi.c
@@ -450,7 +450,7 @@ void ivtv_disable_vbi(struct ivtv *itv)
 }
 
 
-void vbi_work_handler(struct ivtv *itv)
+void ivtv_vbi_work_handler(struct ivtv *itv)
 {
         struct v4l2_sliced_vbi_data data;
 
diff --git a/drivers/media/video/ivtv/ivtv-vbi.h b/drivers/media/video/ivtv/ivtv-vbi.h
index cdaea697b3ec..ec211b49702c 100644
--- a/drivers/media/video/ivtv/ivtv-vbi.h
+++ b/drivers/media/video/ivtv/ivtv-vbi.h
@@ -23,4 +23,4 @@ void ivtv_process_vbi_data(struct ivtv *itv, struct ivtv_buffer *buf,
 int ivtv_used_line(struct ivtv *itv, int line, int field);
 void ivtv_disable_vbi(struct ivtv *itv);
 void ivtv_set_vbi(unsigned long arg);
-void vbi_work_handler(struct ivtv *itv);
+void ivtv_vbi_work_handler(struct ivtv *itv);