V4L/DVB (13429): cx18: Add Memory Descriptor List (MDL) layer to buffer handling

Add a Memory Descriptor List (MDL) layer to buffer handling to implement
scatter-gather I/O.  Currently there is still only 1 buffer per MDL.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

12 files changed, 540 insertions, 173 deletions

diff --git a/drivers/media/video/cx18/cx18-driver.c b/drivers/media/video/cx18/cx18-driver.c
index e12082b8a08d..ba4c3ceffbb3 100644
--- a/drivers/media/video/cx18/cx18-driver.c
+++ b/drivers/media/video/cx18/cx18-driver.c
@@ -669,6 +669,12 @@ static int __devinit cx18_init_struct1(struct cx18 *cx)
         cx->vbi.in.type = V4L2_BUF_TYPE_VBI_CAPTURE;
         cx->vbi.sliced_in = &cx->vbi.in.fmt.sliced;
 
+        /* IVTV style VBI insertion into MPEG streams */
+        INIT_LIST_HEAD(&cx->vbi.sliced_mpeg_buf.list);
+        INIT_LIST_HEAD(&cx->vbi.sliced_mpeg_mdl.list);
+        INIT_LIST_HEAD(&cx->vbi.sliced_mpeg_mdl.buf_list);
+        list_add(&cx->vbi.sliced_mpeg_buf.list,
+                 &cx->vbi.sliced_mpeg_mdl.buf_list);
         return 0;
 }
 
diff --git a/drivers/media/video/cx18/cx18-driver.h b/drivers/media/video/cx18/cx18-driver.h
index 1a899e0773d7..bed8bcc65411 100644
--- a/drivers/media/video/cx18/cx18-driver.h
+++ b/drivers/media/video/cx18/cx18-driver.h
@@ -246,8 +246,8 @@ struct cx18_options {
         int radio;              /* enable/disable radio */
 };
 
-/* per-buffer bit flags */
-#define CX18_F_B_NEED_BUF_SWAP  0       /* this buffer should be byte swapped */
+/* per-mdl bit flags */
+#define CX18_F_M_NEED_SWAP  0   /* mdl buffer data must be endianess swapped */
 
 /* per-stream, s_flags */
 #define CX18_F_S_CLAIMED        3       /* this stream is claimed */
@@ -274,15 +274,26 @@ struct cx18_options {
 struct cx18_buffer {
         struct list_head list;
         dma_addr_t dma_handle;
-        u32 id;
-        unsigned long b_flags;
-        unsigned skipped;
         char *buf;
 
         u32 bytesused;
         u32 readpos;
 };
 
+struct cx18_mdl {
+        struct list_head list;
+        u32 id;         /* index into cx->scb->cpu_mdl[] of 1st cx18_mdl_ent */
+
+        unsigned int skipped;
+        unsigned long m_flags;
+
+        struct list_head buf_list;
+        struct cx18_buffer *curr_buf; /* current buffer in list for reading */
+
+        u32 bytesused;
+        u32 readpos;
+};
+
 struct cx18_queue {
         struct list_head list;
         atomic_t depth;
@@ -346,14 +357,20 @@ struct cx18_stream {
                                    PCI_DMA_NONE */
         wait_queue_head_t waitq;
 
-        /* Buffer Stats */
-        u32 buffers;
-        u32 buf_size;
+        /* Buffers */
+        struct list_head buf_pool;      /* buffers not attached to an MDL */
+        u32 buffers;                    /* total buffers owned by this stream */
+        u32 buf_size;                   /* size in bytes of a single buffer */
+
+        /* MDL sizes - all stream MDLs are the same size */
+        u32 bufs_per_mdl;
+        u32 mdl_size;           /* total bytes in all buffers in a mdl */
 
-        /* Buffer Queues */
-        struct cx18_queue q_free;       /* free buffers */
-        struct cx18_queue q_busy;       /* busy buffers - in use by firmware */
-        struct cx18_queue q_full;       /* full buffers - data for user apps */
+        /* MDL Queues */
+        struct cx18_queue q_free;       /* free - in rotation, not committed */
+        struct cx18_queue q_busy;       /* busy - in use by firmware */
+        struct cx18_queue q_full;       /* full - data for user apps */
+        struct cx18_queue q_idle;       /* idle - not in rotation */
 
         struct work_struct out_work_order;
 
@@ -481,10 +498,11 @@ struct vbi_info {
         u32 inserted_frame;
 
         /*
-         * A dummy driver stream transfer buffer with a copy of the next
+         * A dummy driver stream transfer mdl & buffer with a copy of the next
          * sliced_mpeg_data[] buffer for output to userland apps.
          * Only used in cx18-fileops.c, but its state needs to persist at times.
          */
+        struct cx18_mdl sliced_mpeg_mdl;
         struct cx18_buffer sliced_mpeg_buf;
 };
 
@@ -511,7 +529,6 @@ struct cx18 {
         u8 is_60hz;
         u8 nof_inputs;          /* number of video inputs */
         u8 nof_audio_inputs;    /* number of audio inputs */
-        u16 buffer_id;          /* buffer ID counter */
         u32 v4l2_cap;           /* V4L2 capabilities of card */
         u32 hw_flags;           /* Hardware description of the board */
         unsigned int free_mdl_idx;
diff --git a/drivers/media/video/cx18/cx18-fileops.c b/drivers/media/video/cx18/cx18-fileops.c
index e4a3faebff46..4e278db31cc9 100644
--- a/drivers/media/video/cx18/cx18-fileops.c
+++ b/drivers/media/video/cx18/cx18-fileops.c
@@ -166,11 +166,12 @@ static void cx18_dualwatch(struct cx18 *cx)
 }
 
 
-static struct cx18_buffer *cx18_get_buffer(struct cx18_stream *s, int non_block, int *err)
+static struct cx18_mdl *cx18_get_mdl(struct cx18_stream *s, int non_block,
+                                     int *err)
 {
         struct cx18 *cx = s->cx;
         struct cx18_stream *s_vbi = &cx->streams[CX18_ENC_STREAM_TYPE_VBI];
-        struct cx18_buffer *buf;
+        struct cx18_mdl *mdl;
         DEFINE_WAIT(wait);
 
         *err = 0;
@@ -185,32 +186,33 @@ static struct cx18_buffer *cx18_get_buffer(struct cx18_stream *s, int non_block,
                         }
                         if (test_bit(CX18_F_S_INTERNAL_USE, &s_vbi->s_flags) &&
                             !test_bit(CX18_F_S_APPL_IO, &s_vbi->s_flags)) {
-                                while ((buf = cx18_dequeue(s_vbi, &s_vbi->q_full))) {
+                                while ((mdl = cx18_dequeue(s_vbi,
+                                                           &s_vbi->q_full))) {
                                         /* byteswap and process VBI data */
-                                        cx18_process_vbi_data(cx, buf,
+                                        cx18_process_vbi_data(cx, mdl,
                                                               s_vbi->type);
-                                        cx18_stream_put_buf_fw(s_vbi, buf);
+                                        cx18_stream_put_mdl_fw(s_vbi, mdl);
                                 }
                         }
-                        buf = &cx->vbi.sliced_mpeg_buf;
-                        if (buf->readpos != buf->bytesused)
-                                return buf;
+                        mdl = &cx->vbi.sliced_mpeg_mdl;
+                        if (mdl->readpos != mdl->bytesused)
+                                return mdl;
                 }
 
                 /* do we have new data? */
-                buf = cx18_dequeue(s, &s->q_full);
-                if (buf) {
-                        if (!test_and_clear_bit(CX18_F_B_NEED_BUF_SWAP,
-                                                &buf->b_flags))
-                                return buf;
+                mdl = cx18_dequeue(s, &s->q_full);
+                if (mdl) {
+                        if (!test_and_clear_bit(CX18_F_M_NEED_SWAP,
+                                                &mdl->m_flags))
+                                return mdl;
                         if (s->type == CX18_ENC_STREAM_TYPE_MPG)
                                 /* byteswap MPG data */
-                                cx18_buf_swap(buf);
+                                cx18_mdl_swap(mdl);
                         else {
                                 /* byteswap and process VBI data */
-                                cx18_process_vbi_data(cx, buf, s->type);
+                                cx18_process_vbi_data(cx, mdl, s->type);
                         }
-                        return buf;
+                        return mdl;
                 }
 
                 /* return if end of stream */
@@ -241,21 +243,28 @@ static struct cx18_buffer *cx18_get_buffer(struct cx18_stream *s, int non_block,
         }
 }
 
-static void cx18_setup_sliced_vbi_buf(struct cx18 *cx)
+static void cx18_setup_sliced_vbi_mdl(struct cx18 *cx)
 {
+        struct cx18_mdl *mdl = &cx->vbi.sliced_mpeg_mdl;
+        struct cx18_buffer *buf = &cx->vbi.sliced_mpeg_buf;
         int idx = cx->vbi.inserted_frame % CX18_VBI_FRAMES;
 
-        cx->vbi.sliced_mpeg_buf.buf = cx->vbi.sliced_mpeg_data[idx];
-        cx->vbi.sliced_mpeg_buf.bytesused = cx->vbi.sliced_mpeg_size[idx];
-        cx->vbi.sliced_mpeg_buf.readpos = 0;
+        buf->buf = cx->vbi.sliced_mpeg_data[idx];
+        buf->bytesused = cx->vbi.sliced_mpeg_size[idx];
+        buf->readpos = 0;
+
+        mdl->curr_buf = NULL;
+        mdl->bytesused = cx->vbi.sliced_mpeg_size[idx];
+        mdl->readpos = 0;
 }
 
 static size_t cx18_copy_buf_to_user(struct cx18_stream *s,
-                struct cx18_buffer *buf, char __user *ubuf, size_t ucount)
+        struct cx18_buffer *buf, char __user *ubuf, size_t ucount, bool *stop)
 {
         struct cx18 *cx = s->cx;
         size_t len = buf->bytesused - buf->readpos;
 
+        *stop = false;
         if (len > ucount)
                 len = ucount;
         if (cx->vbi.insert_mpeg && s->type == CX18_ENC_STREAM_TYPE_MPG &&
@@ -335,7 +344,8 @@ static size_t cx18_copy_buf_to_user(struct cx18_stream *s,
                                 /* We declare we actually found a Program Pack*/
                                 cx->search_pack_header = 0; /* expect vid PES */
                                 len = (char *)q - start;
-                                cx18_setup_sliced_vbi_buf(cx);
+                                cx18_setup_sliced_vbi_mdl(cx);
+                                *stop = true;
                                 break;
                         }
                 }
@@ -352,6 +362,60 @@ static size_t cx18_copy_buf_to_user(struct cx18_stream *s,
         return len;
 }
 
+/**
+ * list_entry_is_past_end - check if a previous loop cursor is off list end
+ * @pos:        the type * previously used as a loop cursor.
+ * @head:       the head for your list.
+ * @member:     the name of the list_struct within the struct.
+ *
+ * Check if the entry's list_head is the head of the list, thus it's not a
+ * real entry but was the loop cursor that walked past the end
+ */
+#define list_entry_is_past_end(pos, head, member) \
+        (&pos->member == (head))
+
+static size_t cx18_copy_mdl_to_user(struct cx18_stream *s,
+                struct cx18_mdl *mdl, char __user *ubuf, size_t ucount)
+{
+        size_t tot_written = 0;
+        int rc;
+        bool stop = false;
+
+        if (mdl->curr_buf == NULL)
+                mdl->curr_buf = list_first_entry(&mdl->buf_list,
+                                                 struct cx18_buffer, list);
+
+        if (list_entry_is_past_end(mdl->curr_buf, &mdl->buf_list, list)) {
+                /*
+                 * For some reason we've exhausted the buffers, but the MDL
+                 * object still said some data was unread.
+                 * Fix that and bail out.
+                 */
+                mdl->readpos = mdl->bytesused;
+                return 0;
+        }
+
+        list_for_each_entry_from(mdl->curr_buf, &mdl->buf_list, list) {
+
+                if (mdl->curr_buf->readpos >= mdl->curr_buf->bytesused)
+                        continue;
+
+                rc = cx18_copy_buf_to_user(s, mdl->curr_buf, ubuf + tot_written,
+                                           ucount - tot_written, &stop);
+                if (rc < 0)
+                        return rc;
+                mdl->readpos += rc;
+                tot_written += rc;
+
+                if (stop ||     /* Forced stopping point for VBI insertion */
+                    tot_written >= ucount ||    /* Reader request statisfied */
+                    mdl->curr_buf->readpos < mdl->curr_buf->bytesused ||
+                    mdl->readpos >= mdl->bytesused) /* MDL buffers drained */
+                        break;
+        }
+        return tot_written;
+}
+
 static ssize_t cx18_read(struct cx18_stream *s, char __user *ubuf,
                 size_t tot_count, int non_block)
 {
@@ -373,12 +437,12 @@ static ssize_t cx18_read(struct cx18_stream *s, char __user *ubuf,
                 single_frame = 1;
 
         for (;;) {
-                struct cx18_buffer *buf;
+                struct cx18_mdl *mdl;
                 int rc;
 
-                buf = cx18_get_buffer(s, non_block, &rc);
+                mdl = cx18_get_mdl(s, non_block, &rc);
                 /* if there is no data available... */
-                if (buf == NULL) {
+                if (mdl == NULL) {
                         /* if we got data, then return that regardless */
                         if (tot_written)
                                 break;
@@ -392,20 +456,20 @@ static ssize_t cx18_read(struct cx18_stream *s, char __user *ubuf,
                         return rc;
                 }
 
-                rc = cx18_copy_buf_to_user(s, buf, ubuf + tot_written,
+                rc = cx18_copy_mdl_to_user(s, mdl, ubuf + tot_written,
                                 tot_count - tot_written);
 
-                if (buf != &cx->vbi.sliced_mpeg_buf) {
-                        if (buf->readpos == buf->bytesused)
-                                cx18_stream_put_buf_fw(s, buf);
+                if (mdl != &cx->vbi.sliced_mpeg_mdl) {
+                        if (mdl->readpos == mdl->bytesused)
+                                cx18_stream_put_mdl_fw(s, mdl);
                         else
-                                cx18_push(s, buf, &s->q_full);
-                } else if (buf->readpos == buf->bytesused) {
+                                cx18_push(s, mdl, &s->q_full);
+                } else if (mdl->readpos == mdl->bytesused) {
                         int idx = cx->vbi.inserted_frame % CX18_VBI_FRAMES;
 
                         cx->vbi.sliced_mpeg_size[idx] = 0;
                         cx->vbi.inserted_frame++;
-                        cx->vbi_data_inserted += buf->bytesused;
+                        cx->vbi_data_inserted += mdl->bytesused;
                 }
                 if (rc < 0)
                         return rc;
diff --git a/drivers/media/video/cx18/cx18-ioctl.c b/drivers/media/video/cx18/cx18-ioctl.c
index 6539b031b4eb..3e4fc192fdec 100644
--- a/drivers/media/video/cx18/cx18-ioctl.c
+++ b/drivers/media/video/cx18/cx18-ioctl.c
@@ -910,7 +910,8 @@ static int cx18_log_status(struct file *file, void *fh)
                         continue;
                 CX18_INFO("Stream %s: status 0x%04lx, %d%% of %d KiB (%d buffers) in use\n",
                           s->name, s->s_flags,
-                          atomic_read(&s->q_full.depth) * 100 / s->buffers,
+                          atomic_read(&s->q_full.depth) * s->bufs_per_mdl * 100
+                           / s->buffers,
                           (s->buffers * s->buf_size) / 1024, s->buffers);
         }
         CX18_INFO("Read MPEG/VBI: %lld/%lld bytes\n",
diff --git a/drivers/media/video/cx18/cx18-mailbox.c b/drivers/media/video/cx18/cx18-mailbox.c
index 4a1249a7d46a..f231dd09c720 100644
--- a/drivers/media/video/cx18/cx18-mailbox.c
+++ b/drivers/media/video/cx18/cx18-mailbox.c
@@ -131,13 +131,39 @@ static void dump_mb(struct cx18 *cx, struct cx18_mailbox *mb, char *name)
  * Functions that run in a work_queue work handling context
  */
 
+static void cx18_mdl_send_to_dvb(struct cx18_stream *s, struct cx18_mdl *mdl)
+{
+        struct cx18_buffer *buf;
+
+        if (!s->dvb.enabled || mdl->bytesused == 0)
+                return;
+
+        /* We ignore mdl and buf readpos accounting here - it doesn't matter */
+
+        /* The likely case */
+        if (list_is_singular(&mdl->buf_list)) {
+                buf = list_first_entry(&mdl->buf_list, struct cx18_buffer,
+                                       list);
+                if (buf->bytesused)
+                        dvb_dmx_swfilter(&s->dvb.demux,
+                                         buf->buf, buf->bytesused);
+                return;
+        }
+
+        list_for_each_entry(buf, &mdl->buf_list, list) {
+                if (buf->bytesused == 0)
+                        break;
+                dvb_dmx_swfilter(&s->dvb.demux, buf->buf, buf->bytesused);
+        }
+}
+
 static void epu_dma_done(struct cx18 *cx, struct cx18_in_work_order *order)
 {
         u32 handle, mdl_ack_count, id;
         struct cx18_mailbox *mb;
         struct cx18_mdl_ack *mdl_ack;
         struct cx18_stream *s;
-        struct cx18_buffer *buf;
+        struct cx18_mdl *mdl;
         int i;
 
         mb = &order->mb;
@@ -158,7 +184,7 @@ static void epu_dma_done(struct cx18 *cx, struct cx18_in_work_order *order)
                 id = mdl_ack->id;
                 /*
                  * Simple integrity check for processing a stale (and possibly
-                 * inconsistent mailbox): make sure the buffer id is in the
+                 * inconsistent mailbox): make sure the MDL id is in the
                  * valid range for the stream.
                  *
                  * We go through the trouble of dealing with stale mailboxes
@@ -169,44 +195,42 @@ static void epu_dma_done(struct cx18 *cx, struct cx18_in_work_order *order)
                  * There are occasions when we get a half changed mailbox,
                  * which this check catches for a handle & id mismatch.  If the
                  * handle and id do correspond, the worst case is that we
-                 * completely lost the old buffer, but pick up the new buffer
+                 * completely lost the old MDL, but pick up the new MDL
                  * early (but the new mdl_ack is guaranteed to be good in this
                  * case as the firmware wouldn't point us to a new mdl_ack until
                  * it's filled in).
                  *
-                 * cx18_queue_get buf() will detect the lost buffers
+                 * cx18_queue_get_mdl() will detect the lost MDLs
                  * and send them back to q_free for fw rotation eventually.
                  */
                 if ((order->flags & CX18_F_EWO_MB_STALE_UPON_RECEIPT) &&
                     !(id >= s->mdl_base_idx &&
                       id < (s->mdl_base_idx + s->buffers))) {
                         CX18_WARN("Fell behind! Ignoring stale mailbox with "
-                                  " inconsistent data. Lost buffer for mailbox "
+                                  " inconsistent data. Lost MDL for mailbox "
                                   "seq no %d\n", mb->request);
                         break;
                 }
-                buf = cx18_queue_get_buf(s, id, mdl_ack->data_used);
+                mdl = cx18_queue_get_mdl(s, id, mdl_ack->data_used);
 
-                CX18_DEBUG_HI_DMA("DMA DONE for %s (buffer %d)\n", s->name, id);
-                if (buf == NULL) {
-                        CX18_WARN("Could not find buf %d for stream %s\n",
+                CX18_DEBUG_HI_DMA("DMA DONE for %s (MDL %d)\n", s->name, id);
+                if (mdl == NULL) {
+                        CX18_WARN("Could not find MDL %d for stream %s\n",
                                   id, s->name);
                         continue;
                 }
 
                 CX18_DEBUG_HI_DMA("%s recv bytesused = %d\n",
-                                  s->name, buf->bytesused);
+                                  s->name, mdl->bytesused);
 
                 if (s->type != CX18_ENC_STREAM_TYPE_TS)
-                        cx18_enqueue(s, buf, &s->q_full);
+                        cx18_enqueue(s, mdl, &s->q_full);
                 else {
-                        if (s->dvb.enabled)
-                                dvb_dmx_swfilter(&s->dvb.demux, buf->buf,
-                                                 buf->bytesused);
-                        cx18_enqueue(s, buf, &s->q_free);
+                        cx18_mdl_send_to_dvb(s, mdl);
+                        cx18_enqueue(s, mdl, &s->q_free);
                 }
         }
-        /* Put as many buffers as possible back into fw use */
+        /* Put as many MDLs as possible back into fw use */
         cx18_stream_load_fw_queue(s);
 
         wake_up(&cx->dma_waitq);
@@ -616,7 +640,7 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
 
         /*
          * Wait for XPU to perform extra actions for the caller in some cases.
-         * e.g. CX18_CPU_DE_RELEASE_MDL will cause the CPU to send all buffers
+         * e.g. CX18_CPU_DE_RELEASE_MDL will cause the CPU to send all MDLs
          * back in a burst shortly thereafter
          */
         if (info->flags & API_SLOW)
diff --git a/drivers/media/video/cx18/cx18-mailbox.h b/drivers/media/video/cx18/cx18-mailbox.h
index e23aaac5b280..5ea07359904c 100644
--- a/drivers/media/video/cx18/cx18-mailbox.h
+++ b/drivers/media/video/cx18/cx18-mailbox.h
@@ -39,14 +39,14 @@
 struct cx18;
 
 /*
- * This structure is used by CPU to provide completed buffers information
- * Its structure is dictrated by the layout of the SCB, required by the
+ * This structure is used by CPU to provide completed MDL & buffers information.
+ * Its structure is dictated by the layout of the SCB, required by the
  * firmware, but its defintion needs to be here, instead of in cx18-scb.h,
  * for mailbox work order scheduling
  */
 struct cx18_mdl_ack {
     u32 id;        /* ID of a completed MDL */
-    u32 data_used; /* Total data filled in the MDL for buffer 'id' */
+    u32 data_used; /* Total data filled in the MDL with 'id' */
 };
 
 /* The cx18_mailbox struct is the mailbox structure which is used for passing
diff --git a/drivers/media/video/cx18/cx18-queue.c b/drivers/media/video/cx18/cx18-queue.c
index b9bd4ff5535e..c1a49ecf9d98 100644
--- a/drivers/media/video/cx18/cx18-queue.c
+++ b/drivers/media/video/cx18/cx18-queue.c
@@ -26,6 +26,7 @@
 #include "cx18-queue.h"
 #include "cx18-streams.h"
 #include "cx18-scb.h"
+#include "cx18-io.h"
 
 void cx18_buf_swap(struct cx18_buffer *buf)
 {
@@ -35,6 +36,17 @@ void cx18_buf_swap(struct cx18_buffer *buf)
                 swab32s((u32 *)(buf->buf + i));
 }
 
+void _cx18_mdl_swap(struct cx18_mdl *mdl)
+{
+        struct cx18_buffer *buf;
+
+        list_for_each_entry(buf, &mdl->buf_list, list) {
+                if (buf->bytesused == 0)
+                        break;
+                cx18_buf_swap(buf);
+        }
+}
+
 void cx18_queue_init(struct cx18_queue *q)
 {
         INIT_LIST_HEAD(&q->list);
@@ -42,15 +54,16 @@ void cx18_queue_init(struct cx18_queue *q)
         q->bytesused = 0;
 }
 
-struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
+struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_mdl *mdl,
                                  struct cx18_queue *q, int to_front)
 {
-        /* clear the buffer if it is not to be enqueued to the full queue */
+        /* clear the mdl if it is not to be enqueued to the full queue */
         if (q != &s->q_full) {
-                buf->bytesused = 0;
-                buf->readpos = 0;
-                buf->b_flags = 0;
-                buf->skipped = 0;
+                mdl->bytesused = 0;
+                mdl->readpos = 0;
+                mdl->m_flags = 0;
+                mdl->skipped = 0;
+                mdl->curr_buf = NULL;
         }
 
         /* q_busy is restricted to a max buffer count imposed by firmware */
@@ -61,125 +74,270 @@ struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
         spin_lock(&q->lock);
 
         if (to_front)
-                list_add(&buf->list, &q->list); /* LIFO */
+                list_add(&mdl->list, &q->list); /* LIFO */
         else
-                list_add_tail(&buf->list, &q->list); /* FIFO */
-        q->bytesused += buf->bytesused - buf->readpos;
+                list_add_tail(&mdl->list, &q->list); /* FIFO */
+        q->bytesused += mdl->bytesused - mdl->readpos;
         atomic_inc(&q->depth);
 
         spin_unlock(&q->lock);
         return q;
 }
 
-struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
+struct cx18_mdl *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q)
 {
-        struct cx18_buffer *buf = NULL;
+        struct cx18_mdl *mdl = NULL;
 
         spin_lock(&q->lock);
         if (!list_empty(&q->list)) {
-                buf = list_first_entry(&q->list, struct cx18_buffer, list);
-                list_del_init(&buf->list);
-                q->bytesused -= buf->bytesused - buf->readpos;
-                buf->skipped = 0;
+                mdl = list_first_entry(&q->list, struct cx18_mdl, list);
+                list_del_init(&mdl->list);
+                q->bytesused -= mdl->bytesused - mdl->readpos;
+                mdl->skipped = 0;
                 atomic_dec(&q->depth);
         }
         spin_unlock(&q->lock);
-        return buf;
+        return mdl;
+}
+
+static void _cx18_mdl_set_buf_bytesused(struct cx18_stream *s,
+                                        struct cx18_mdl *mdl)
+{
+        struct cx18_buffer *buf;
+        u32 buf_size = s->buf_size;
+        u32 bytesused = mdl->bytesused;
+
+        list_for_each_entry(buf, &mdl->buf_list, list) {
+                buf->readpos = 0;
+                if (bytesused >= buf_size) {
+                        buf->bytesused = buf_size;
+                        bytesused -= buf_size;
+                } else {
+                        buf->bytesused = bytesused;
+                        bytesused = 0;
+                }
+        }
 }
 
-struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
+static inline void cx18_mdl_set_buf_bytesused(struct cx18_stream *s,
+                                              struct cx18_mdl *mdl)
+{
+        struct cx18_buffer *buf;
+
+        if (list_is_singular(&mdl->buf_list)) {
+                buf = list_first_entry(&mdl->buf_list, struct cx18_buffer,
+                                       list);
+                buf->bytesused = mdl->bytesused;
+                buf->readpos = 0;
+        } else {
+                _cx18_mdl_set_buf_bytesused(s, mdl);
+        }
+}
+
+struct cx18_mdl *cx18_queue_get_mdl(struct cx18_stream *s, u32 id,
         u32 bytesused)
 {
         struct cx18 *cx = s->cx;
-        struct cx18_buffer *buf;
-        struct cx18_buffer *tmp;
-        struct cx18_buffer *ret = NULL;
+        struct cx18_mdl *mdl;
+        struct cx18_mdl *tmp;
+        struct cx18_mdl *ret = NULL;
         LIST_HEAD(sweep_up);
 
         /*
          * We don't have to acquire multiple q locks here, because we are
          * serialized by the single threaded work handler.
-         * Buffers from the firmware will thus remain in order as
+         * MDLs from the firmware will thus remain in order as
          * they are moved from q_busy to q_full or to the dvb ring buffer.
          */
         spin_lock(&s->q_busy.lock);
-        list_for_each_entry_safe(buf, tmp, &s->q_busy.list, list) {
+        list_for_each_entry_safe(mdl, tmp, &s->q_busy.list, list) {
                 /*
                  * We should find what the firmware told us is done,
                  * right at the front of the queue.  If we don't, we likely have
-                 * missed a buffer done message from the firmware.
-                 * Once we skip a buffer repeatedly, relative to the size of
+                 * missed an mdl done message from the firmware.
+                 * Once we skip an mdl repeatedly, relative to the size of
                  * q_busy, we have high confidence we've missed it.
                  */
-                if (buf->id != id) {
-                        buf->skipped++;
-                        if (buf->skipped >= atomic_read(&s->q_busy.depth)-1) {
-                                /* buffer must have fallen out of rotation */
-                                CX18_WARN("Skipped %s, buffer %d, %d "
+                if (mdl->id != id) {
+                        mdl->skipped++;
+                        if (mdl->skipped >= atomic_read(&s->q_busy.depth)-1) {
+                                /* mdl must have fallen out of rotation */
+                                CX18_WARN("Skipped %s, MDL %d, %d "
                                           "times - it must have dropped out of "
-                                          "rotation\n", s->name, buf->id,
-                                          buf->skipped);
+                                          "rotation\n", s->name, mdl->id,
+                                          mdl->skipped);
                                 /* Sweep it up to put it back into rotation */
-                                list_move_tail(&buf->list, &sweep_up);
+                                list_move_tail(&mdl->list, &sweep_up);
                                 atomic_dec(&s->q_busy.depth);
                         }
                         continue;
                 }
                 /*
-                 * We pull the desired buffer off of the queue here.  Something
+                 * We pull the desired mdl off of the queue here.  Something
                  * will have to put it back on a queue later.
                  */
-                list_del_init(&buf->list);
+                list_del_init(&mdl->list);
                 atomic_dec(&s->q_busy.depth);
-                ret = buf;
+                ret = mdl;
                 break;
         }
         spin_unlock(&s->q_busy.lock);
 
         /*
-         * We found the buffer for which we were looking.  Get it ready for
+         * We found the mdl for which we were looking.  Get it ready for
          * the caller to put on q_full or in the dvb ring buffer.
          */
         if (ret != NULL) {
                 ret->bytesused = bytesused;
                 ret->skipped = 0;
-                /* readpos and b_flags were 0'ed when the buf went on q_busy */
-                cx18_buf_sync_for_cpu(s, ret);
+                /* 0'ed readpos, m_flags & curr_buf when mdl went on q_busy */
+                cx18_mdl_set_buf_bytesused(s, ret);
+                cx18_mdl_sync_for_cpu(s, ret);
                 if (s->type != CX18_ENC_STREAM_TYPE_TS)
-                        set_bit(CX18_F_B_NEED_BUF_SWAP, &ret->b_flags);
+                        set_bit(CX18_F_M_NEED_SWAP, &ret->m_flags);
         }
 
-        /* Put any buffers the firmware is ignoring back into normal rotation */
-        list_for_each_entry_safe(buf, tmp, &sweep_up, list) {
-                list_del_init(&buf->list);
-                cx18_enqueue(s, buf, &s->q_free);
+        /* Put any mdls the firmware is ignoring back into normal rotation */
+        list_for_each_entry_safe(mdl, tmp, &sweep_up, list) {
+                list_del_init(&mdl->list);
+                cx18_enqueue(s, mdl, &s->q_free);
         }
         return ret;
 }
 
-/* Move all buffers of a queue to q_free, while flushing the buffers */
-static void cx18_queue_flush(struct cx18_stream *s, struct cx18_queue *q)
+/* Move all mdls of a queue, while flushing the mdl */
+static void cx18_queue_flush(struct cx18_stream *s,
+                             struct cx18_queue *q_src, struct cx18_queue *q_dst)
 {
-        struct cx18_buffer *buf;
+        struct cx18_mdl *mdl;
 
-        if (q == &s->q_free)
+        /* It only makes sense to flush to q_free or q_idle */
+        if (q_src == q_dst || q_dst == &s->q_full || q_dst == &s->q_busy)
                 return;
 
-        spin_lock(&q->lock);
-        while (!list_empty(&q->list)) {
-                buf = list_first_entry(&q->list, struct cx18_buffer, list);
-                list_move_tail(&buf->list, &s->q_free.list);
-                buf->bytesused = buf->readpos = buf->b_flags = buf->skipped = 0;
-                atomic_inc(&s->q_free.depth);
+        spin_lock(&q_src->lock);
+        spin_lock(&q_dst->lock);
+        while (!list_empty(&q_src->list)) {
+                mdl = list_first_entry(&q_src->list, struct cx18_mdl, list);
+                list_move_tail(&mdl->list, &q_dst->list);
+                mdl->bytesused = 0;
+                mdl->readpos = 0;
+                mdl->m_flags = 0;
+                mdl->skipped = 0;
+                mdl->curr_buf = NULL;
+                atomic_inc(&q_dst->depth);
         }
-        cx18_queue_init(q);
-        spin_unlock(&q->lock);
+        cx18_queue_init(q_src);
+        spin_unlock(&q_src->lock);
+        spin_unlock(&q_dst->lock);
 }
 
 void cx18_flush_queues(struct cx18_stream *s)
 {
-        cx18_queue_flush(s, &s->q_busy);
-        cx18_queue_flush(s, &s->q_full);
+        cx18_queue_flush(s, &s->q_busy, &s->q_free);
+        cx18_queue_flush(s, &s->q_full, &s->q_free);
+}
+
+/*
+ * Note, s->buf_pool is not protected by a lock,
+ * the stream better not have *anything* going on when calling this
+ */
+void cx18_unload_queues(struct cx18_stream *s)
+{
+        struct cx18_queue *q_idle = &s->q_idle;
+        struct cx18_mdl *mdl;
+        struct cx18_buffer *buf;
+
+        /* Move all MDLS to q_idle */
+        cx18_queue_flush(s, &s->q_busy, q_idle);
+        cx18_queue_flush(s, &s->q_full, q_idle);
+        cx18_queue_flush(s, &s->q_free, q_idle);
+
+        /* Reset MDL id's and move all buffers back to the stream's buf_pool */
+        spin_lock(&q_idle->lock);
+        list_for_each_entry(mdl, &q_idle->list, list) {
+                while (!list_empty(&mdl->buf_list)) {
+                        buf = list_first_entry(&mdl->buf_list,
+                                               struct cx18_buffer, list);
+                        list_move_tail(&buf->list, &s->buf_pool);
+                        buf->bytesused = 0;
+                        buf->readpos = 0;
+                }
+                mdl->id = s->mdl_base_idx; /* reset id to a "safe" value */
+                /* all other mdl fields were cleared by cx18_queue_flush() */
+        }
+        spin_unlock(&q_idle->lock);
+}
+
+/*
+ * Note, s->buf_pool is not protected by a lock,
+ * the stream better not have *anything* going on when calling this
+ */
+void cx18_load_queues(struct cx18_stream *s)
+{
+        struct cx18 *cx = s->cx;
+        struct cx18_mdl *mdl;
+        struct cx18_buffer *buf;
+        int mdl_id;
+        int i;
+
+        /*
+         * Attach buffers to MDLs, give the MDLs ids, and add MDLs to q_free
+         * Excess MDLs are left on q_idle
+         * Excess buffers are left in buf_pool and/or on an MDL in q_idle
+         */
+        mdl_id = s->mdl_base_idx;
+        for (mdl = cx18_dequeue(s, &s->q_idle), i = s->bufs_per_mdl;
+             mdl != NULL && i == s->bufs_per_mdl;
+             mdl = cx18_dequeue(s, &s->q_idle)) {
+
+                mdl->id = mdl_id;
+
+                for (i = 0; i < s->bufs_per_mdl; i++) {
+                        if (list_empty(&s->buf_pool))
+                                break;
+
+                        buf = list_first_entry(&s->buf_pool, struct cx18_buffer,
+                                               list);
+                        list_move_tail(&buf->list, &mdl->buf_list);
+
+                        /* update the firmware's MDL array with this buffer */
+                        cx18_writel(cx, buf->dma_handle,
+                                    &cx->scb->cpu_mdl[mdl_id + i].paddr);
+                        cx18_writel(cx, s->buf_size,
+                                    &cx->scb->cpu_mdl[mdl_id + i].length);
+                }
+
+                if (i == s->bufs_per_mdl)
+                        cx18_enqueue(s, mdl, &s->q_free);
+                else
+                        cx18_push(s, mdl, &s->q_idle); /* not enough buffers */
+                mdl_id += i;
+        }
+}
+
+void _cx18_mdl_sync_for_cpu(struct cx18_stream *s, struct cx18_mdl *mdl)
+{
+        int dma = s->dma;
+        u32 buf_size = s->buf_size;
+        struct pci_dev *pci_dev = s->cx->pci_dev;
+        struct cx18_buffer *buf;
+
+        list_for_each_entry(buf, &mdl->buf_list, list)
+                pci_dma_sync_single_for_cpu(pci_dev, buf->dma_handle,
+                                            buf_size, dma);
+}
+
+void _cx18_mdl_sync_for_device(struct cx18_stream *s, struct cx18_mdl *mdl)
+{
+        int dma = s->dma;
+        u32 buf_size = s->buf_size;
+        struct pci_dev *pci_dev = s->cx->pci_dev;
+        struct cx18_buffer *buf;
+
+        list_for_each_entry(buf, &mdl->buf_list, list)
+                pci_dma_sync_single_for_device(pci_dev, buf->dma_handle,
+                                               buf_size, dma);
 }
 
 int cx18_stream_alloc(struct cx18_stream *s)
@@ -207,24 +365,40 @@ int cx18_stream_alloc(struct cx18_stream *s)
 
         s->mdl_base_idx = cx->free_mdl_idx;
 
-        /* allocate stream buffers. Initially all buffers are in q_free. */
+        /* allocate stream buffers and MDLs */
         for (i = 0; i < s->buffers; i++) {
-                struct cx18_buffer *buf = kzalloc(sizeof(struct cx18_buffer),
-                                                GFP_KERNEL|__GFP_NOWARN);
+                struct cx18_mdl *mdl;
+                struct cx18_buffer *buf;
 
-                if (buf == NULL)
+                /* 1 MDL per buffer to handle the worst & also default case */
+                mdl = kzalloc(sizeof(struct cx18_mdl), GFP_KERNEL|__GFP_NOWARN);
+                if (mdl == NULL)
                         break;
+
+                buf = kzalloc(sizeof(struct cx18_buffer),
+                                GFP_KERNEL|__GFP_NOWARN);
+                if (buf == NULL) {
+                        kfree(mdl);
+                        break;
+                }
+
                 buf->buf = kmalloc(s->buf_size, GFP_KERNEL|__GFP_NOWARN);
                 if (buf->buf == NULL) {
+                        kfree(mdl);
                         kfree(buf);
                         break;
                 }
-                buf->id = cx->buffer_id++;
+
+                INIT_LIST_HEAD(&mdl->list);
+                INIT_LIST_HEAD(&mdl->buf_list);
+                mdl->id = s->mdl_base_idx; /* a somewhat safe value */
+                cx18_enqueue(s, mdl, &s->q_idle);
+
                 INIT_LIST_HEAD(&buf->list);
                 buf->dma_handle = pci_map_single(s->cx->pci_dev,
                                 buf->buf, s->buf_size, s->dma);
                 cx18_buf_sync_for_cpu(s, buf);
-                cx18_enqueue(s, buf, &s->q_free);
+                list_add_tail(&buf->list, &s->buf_pool);
         }
         if (i == s->buffers) {
                 cx->free_mdl_idx += s->buffers;
@@ -237,13 +411,21 @@ int cx18_stream_alloc(struct cx18_stream *s)
 
 void cx18_stream_free(struct cx18_stream *s)
 {
+        struct cx18_mdl *mdl;
         struct cx18_buffer *buf;
 
-        /* move all buffers to q_free */
-        cx18_flush_queues(s);
+        /* move all buffers to buf_pool and all MDLs to q_idle */
+        cx18_unload_queues(s);
+
+        /* empty q_idle */
+        while ((mdl = cx18_dequeue(s, &s->q_idle)))
+                kfree(mdl);
+
+        /* empty buf_pool */
+        while (!list_empty(&s->buf_pool)) {
+                buf = list_first_entry(&s->buf_pool, struct cx18_buffer, list);
+                list_del_init(&buf->list);
 
-        /* empty q_free */
-        while ((buf = cx18_dequeue(s, &s->q_free))) {
                 pci_unmap_single(s->cx->pci_dev, buf->dma_handle,
                                 s->buf_size, s->dma);
                 kfree(buf->buf);
diff --git a/drivers/media/video/cx18/cx18-queue.h b/drivers/media/video/cx18/cx18-queue.h
index 4de06269d88f..96747e5e7c3c 100644
--- a/drivers/media/video/cx18/cx18-queue.h
+++ b/drivers/media/video/cx18/cx18-queue.h
@@ -33,6 +33,19 @@ static inline void cx18_buf_sync_for_cpu(struct cx18_stream *s,
                                 s->buf_size, s->dma);
 }
 
+void _cx18_mdl_sync_for_cpu(struct cx18_stream *s, struct cx18_mdl *mdl);
+
+static inline void cx18_mdl_sync_for_cpu(struct cx18_stream *s,
+                                         struct cx18_mdl *mdl)
+{
+        if (list_is_singular(&mdl->buf_list))
+                cx18_buf_sync_for_cpu(s, list_first_entry(&mdl->buf_list,
+                                                          struct cx18_buffer,
+                                                          list));
+        else
+                _cx18_mdl_sync_for_cpu(s, mdl);
+}
+
 static inline void cx18_buf_sync_for_device(struct cx18_stream *s,
         struct cx18_buffer *buf)
 {
@@ -40,32 +53,59 @@ static inline void cx18_buf_sync_for_device(struct cx18_stream *s,
                                 s->buf_size, s->dma);
 }
 
+void _cx18_mdl_sync_for_device(struct cx18_stream *s, struct cx18_mdl *mdl);
+
+static inline void cx18_mdl_sync_for_device(struct cx18_stream *s,
+                                            struct cx18_mdl *mdl)
+{
+        if (list_is_singular(&mdl->buf_list))
+                cx18_buf_sync_for_device(s, list_first_entry(&mdl->buf_list,
+                                                             struct cx18_buffer,
+                                                             list));
+        else
+                _cx18_mdl_sync_for_device(s, mdl);
+}
+
 void cx18_buf_swap(struct cx18_buffer *buf);
+void _cx18_mdl_swap(struct cx18_mdl *mdl);
+
+static inline void cx18_mdl_swap(struct cx18_mdl *mdl)
+{
+        if (list_is_singular(&mdl->buf_list))
+                cx18_buf_swap(list_first_entry(&mdl->buf_list,
+                                               struct cx18_buffer, list));
+        else
+                _cx18_mdl_swap(mdl);
+}
 
 /* cx18_queue utility functions */
-struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
+struct cx18_queue *_cx18_enqueue(struct cx18_stream *s, struct cx18_mdl *mdl,
                                  struct cx18_queue *q, int to_front);
 
 static inline
-struct cx18_queue *cx18_enqueue(struct cx18_stream *s, struct cx18_buffer *buf,
+struct cx18_queue *cx18_enqueue(struct cx18_stream *s, struct cx18_mdl *mdl,
                                 struct cx18_queue *q)
 {
-        return _cx18_enqueue(s, buf, q, 0); /* FIFO */
+        return _cx18_enqueue(s, mdl, q, 0); /* FIFO */
 }
 
 static inline
-struct cx18_queue *cx18_push(struct cx18_stream *s, struct cx18_buffer *buf,
+struct cx18_queue *cx18_push(struct cx18_stream *s, struct cx18_mdl *mdl,
                              struct cx18_queue *q)
 {
-        return _cx18_enqueue(s, buf, q, 1); /* LIFO */
+        return _cx18_enqueue(s, mdl, q, 1); /* LIFO */
 }
 
 void cx18_queue_init(struct cx18_queue *q);
-struct cx18_buffer *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q);
-struct cx18_buffer *cx18_queue_get_buf(struct cx18_stream *s, u32 id,
+struct cx18_mdl *cx18_dequeue(struct cx18_stream *s, struct cx18_queue *q);
+struct cx18_mdl *cx18_queue_get_mdl(struct cx18_stream *s, u32 id,
         u32 bytesused);
 void cx18_flush_queues(struct cx18_stream *s);
 
+/* queue MDL reconfiguration helpers */
+void cx18_unload_queues(struct cx18_stream *s);
+void cx18_load_queues(struct cx18_stream *s);
+
 /* cx18_stream utility functions */
 int cx18_stream_alloc(struct cx18_stream *s);
 void cx18_stream_free(struct cx18_stream *s);
diff --git a/drivers/media/video/cx18/cx18-streams.c b/drivers/media/video/cx18/cx18-streams.c
index 10228c5ca5a0..9f8adda6f261 100644
--- a/drivers/media/video/cx18/cx18-streams.c
+++ b/drivers/media/video/cx18/cx18-streams.c
@@ -115,6 +115,9 @@ static void cx18_stream_init(struct cx18 *cx, int type)
         s->dma = cx18_stream_info[type].dma;
         s->buffers = cx->stream_buffers[type];
         s->buf_size = cx->stream_buf_size[type];
+        INIT_LIST_HEAD(&s->buf_pool);
+        s->bufs_per_mdl = 1;
+        s->mdl_size = s->buf_size * s->bufs_per_mdl;
 
         init_waitqueue_head(&s->waitq);
         s->id = -1;
@@ -124,6 +127,8 @@ static void cx18_stream_init(struct cx18 *cx, int type)
         cx18_queue_init(&s->q_busy);
         spin_lock_init(&s->q_full.lock);
         cx18_queue_init(&s->q_full);
+        spin_lock_init(&s->q_idle.lock);
+        cx18_queue_init(&s->q_idle);
 
         INIT_WORK(&s->out_work_order, cx18_out_work_handler);
 }
@@ -441,8 +446,8 @@ static void cx18_vbi_setup(struct cx18_stream *s)
 }
 
 static
-struct cx18_queue *_cx18_stream_put_buf_fw(struct cx18_stream *s,
-                                           struct cx18_buffer *buf)
+struct cx18_queue *_cx18_stream_put_mdl_fw(struct cx18_stream *s,
+                                           struct cx18_mdl *mdl)
 {
         struct cx18 *cx = s->cx;
         struct cx18_queue *q;
@@ -451,16 +456,16 @@ struct cx18_queue *_cx18_stream_put_buf_fw(struct cx18_stream *s,
         if (s->handle == CX18_INVALID_TASK_HANDLE ||
             test_bit(CX18_F_S_STOPPING, &s->s_flags) ||
             !test_bit(CX18_F_S_STREAMING, &s->s_flags))
-                return cx18_enqueue(s, buf, &s->q_free);
+                return cx18_enqueue(s, mdl, &s->q_free);
 
-        q = cx18_enqueue(s, buf, &s->q_busy);
+        q = cx18_enqueue(s, mdl, &s->q_busy);
         if (q != &s->q_busy)
-                return q; /* The firmware has the max buffers it can handle */
+                return q; /* The firmware has the max MDLs it can handle */
 
-        cx18_buf_sync_for_device(s, buf);
+        cx18_mdl_sync_for_device(s, mdl);
         cx18_vapi(cx, CX18_CPU_DE_SET_MDL, 5, s->handle,
-                  (void __iomem *) &cx->scb->cpu_mdl[buf->id] - cx->enc_mem,
-                  1, buf->id, s->buf_size);
+                  (void __iomem *) &cx->scb->cpu_mdl[mdl->id] - cx->enc_mem,
+                  s->bufs_per_mdl, mdl->id, s->mdl_size);
         return q;
 }
 
@@ -468,7 +473,7 @@ static
 void _cx18_stream_load_fw_queue(struct cx18_stream *s)
 {
         struct cx18_queue *q;
-        struct cx18_buffer *buf;
+        struct cx18_mdl *mdl;
 
         if (atomic_read(&s->q_free.depth) == 0 ||
             atomic_read(&s->q_busy.depth) >= CX18_MAX_FW_MDLS_PER_STREAM)
@@ -476,10 +481,10 @@ void _cx18_stream_load_fw_queue(struct cx18_stream *s)
 
         /* Move from q_free to q_busy notifying the firmware, until the limit */
         do {
-                buf = cx18_dequeue(s, &s->q_free);
-                if (buf == NULL)
+                mdl = cx18_dequeue(s, &s->q_free);
+                if (mdl == NULL)
                         break;
-                q = _cx18_stream_put_buf_fw(s, buf);
+                q = _cx18_stream_put_mdl_fw(s, mdl);
         } while (atomic_read(&s->q_busy.depth) < CX18_MAX_FW_MDLS_PER_STREAM
                  && q == &s->q_busy);
 }
@@ -492,11 +497,21 @@ void cx18_out_work_handler(struct work_struct *work)
         _cx18_stream_load_fw_queue(s);
 }
 
+static void cx18_stream_configure_mdls(struct cx18_stream *s)
+{
+        cx18_unload_queues(s);
+
+        /* For now */
+        s->bufs_per_mdl = 1;
+        s->mdl_size = s->buf_size * s->bufs_per_mdl;
+
+        cx18_load_queues(s);
+}
+
 int cx18_start_v4l2_encode_stream(struct cx18_stream *s)
 {
         u32 data[MAX_MB_ARGUMENTS];
         struct cx18 *cx = s->cx;
-        struct cx18_buffer *buf;
         int captype = 0;
         struct cx18_api_func_private priv;
 
@@ -619,14 +634,7 @@ int cx18_start_v4l2_encode_stream(struct cx18_stream *s)
                 (void __iomem *)&cx->scb->cpu_mdl_ack[s->type][1] - cx->enc_mem);
 
         /* Init all the cpu_mdls for this stream */
-        cx18_flush_queues(s);
-        spin_lock(&s->q_free.lock);
-        list_for_each_entry(buf, &s->q_free.list, list) {
-                cx18_writel(cx, buf->dma_handle,
-                                        &cx->scb->cpu_mdl[buf->id].paddr);
-                cx18_writel(cx, s->buf_size, &cx->scb->cpu_mdl[buf->id].length);
-        }
-        spin_unlock(&s->q_free.lock);
+        cx18_stream_configure_mdls(s);
         _cx18_stream_load_fw_queue(s);
 
         /* begin_capture */
diff --git a/drivers/media/video/cx18/cx18-streams.h b/drivers/media/video/cx18/cx18-streams.h
index 1afc3fd9d822..4a01db5e5a35 100644
--- a/drivers/media/video/cx18/cx18-streams.h
+++ b/drivers/media/video/cx18/cx18-streams.h
@@ -28,18 +28,18 @@ int cx18_streams_setup(struct cx18 *cx);
 int cx18_streams_register(struct cx18 *cx);
 void cx18_streams_cleanup(struct cx18 *cx, int unregister);
 
-/* Related to submission of buffers to firmware */
+/* Related to submission of mdls to firmware */
 static inline void cx18_stream_load_fw_queue(struct cx18_stream *s)
 {
         struct cx18 *cx = s->cx;
         queue_work(cx->out_work_queue, &s->out_work_order);
 }
 
-static inline void cx18_stream_put_buf_fw(struct cx18_stream *s,
-                                          struct cx18_buffer *buf)
+static inline void cx18_stream_put_mdl_fw(struct cx18_stream *s,
+                                          struct cx18_mdl *mdl)
 {
-        /* Put buf on q_free; the out work handler will move buf(s) to q_busy */
-        cx18_enqueue(s, buf, &s->q_free);
+        /* Put mdl on q_free; the out work handler will move mdl(s) to q_busy */
+        cx18_enqueue(s, mdl, &s->q_free);
         cx18_stream_load_fw_queue(s);
 }
 
diff --git a/drivers/media/video/cx18/cx18-vbi.c b/drivers/media/video/cx18/cx18-vbi.c
index c2aef4add31d..574c1c6974f8 100644
--- a/drivers/media/video/cx18/cx18-vbi.c
+++ b/drivers/media/video/cx18/cx18-vbi.c
@@ -105,6 +105,7 @@ static void copy_vbi_data(struct cx18 *cx, int lines, u32 pts_stamp)
 
 /* Compress raw VBI format, removes leading SAV codes and surplus space
    after the frame.  Returns new compressed size. */
+/* FIXME - this function ignores the input size. */
 static u32 compress_raw_buf(struct cx18 *cx, u8 *buf, u32 size, u32 hdr_size)
 {
         u32 line_size = vbi_active_samples;
@@ -185,8 +186,7 @@ static u32 compress_sliced_buf(struct cx18 *cx, u8 *buf, u32 size,
         return line;
 }
 
-void cx18_process_vbi_data(struct cx18 *cx, struct cx18_buffer *buf,
-                           int streamtype)
+static void _cx18_process_vbi_data(struct cx18 *cx, struct cx18_buffer *buf)
 {
         /*
          * The CX23418 provides a 12 byte header in its raw VBI buffers to us:
@@ -203,9 +203,6 @@ void cx18_process_vbi_data(struct cx18 *cx, struct cx18_buffer *buf,
         u32 pts;
         int lines;
 
-        if (streamtype != CX18_ENC_STREAM_TYPE_VBI)
-                return;
-
         /*
          * The CX23418 sends us data that is 32 bit little-endian swapped,
          * but we want the raw VBI bytes in the order they were in the raster
@@ -250,3 +247,31 @@ void cx18_process_vbi_data(struct cx18 *cx, struct cx18_buffer *buf,
                 copy_vbi_data(cx, lines, pts);
         cx->vbi.frame++;
 }
+
+void cx18_process_vbi_data(struct cx18 *cx, struct cx18_mdl *mdl,
+                           int streamtype)
+{
+        struct cx18_buffer *buf;
+        u32 orig_used;
+
+        if (streamtype != CX18_ENC_STREAM_TYPE_VBI)
+                return;
+
+        /*
+         * Big assumption here:
+         * Every buffer hooked to the MDL's buf_list is a complete VBI frame
+         * that ends at the end of the buffer.
+         *
+         * To assume anything else would make the code in this file
+         * more complex, or require extra memcpy()'s to make the
+         * buffers satisfy the above assumption.  It's just simpler to set
+         * up the encoder buffer transfers to make the assumption true.
+         */
+        list_for_each_entry(buf, &mdl->buf_list, list) {
+                orig_used = buf->bytesused;
+                if (orig_used == 0)
+                        break;
+                _cx18_process_vbi_data(cx, buf);
+                mdl->bytesused -= (orig_used - buf->bytesused);
+        }
+}
diff --git a/drivers/media/video/cx18/cx18-vbi.h b/drivers/media/video/cx18/cx18-vbi.h
index e7e1ae427f34..b365cf4b4668 100644
--- a/drivers/media/video/cx18/cx18-vbi.h
+++ b/drivers/media/video/cx18/cx18-vbi.h
@@ -21,6 +21,6 @@
  *  02111-1307  USA
  */
 
-void cx18_process_vbi_data(struct cx18 *cx, struct cx18_buffer *buf,
+void cx18_process_vbi_data(struct cx18 *cx, struct cx18_mdl *mdl,
                            int streamtype);
 int cx18_used_line(struct cx18 *cx, int line, int field);