V4L/DVB (6716): ivtv: yuv interlace mode change

Interlace mode selection code moved into the frame setup phase, so it's now
run before the frame is loaded into a hardware buffer. Given that it can
affect how a new frame is displayed, it was a bit stupid running it after the
frame was already visible.

A few stray interlace related variables which were linked to individual frames
have now been moved into the yuv_frame_info struct. This means that all
variables linked to a specific frame are in the same place & not scattered.

Minor code reformatting in areas touched by the above changes.

Signed-off-by: Ian Armstrong <ian@iarmst.demon.co.uk>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 185 insertions, 197 deletions

diff --git a/drivers/media/video/ivtv/ivtv-yuv.c b/drivers/media/video/ivtv/ivtv-yuv.c
index a23108fae4fd..cd42db9b5a15 100644
--- a/drivers/media/video/ivtv/ivtv-yuv.c
+++ b/drivers/media/video/ivtv/ivtv-yuv.c
@@ -39,19 +39,20 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma,
 {
         struct ivtv_dma_page_info y_dma;
         struct ivtv_dma_page_info uv_dma;
-
+        struct yuv_playback_info *yi = &itv->yuv_info;
+        u8 frame = yi->draw_frame;
+        struct yuv_frame_info *f = &yi->new_frame_info[frame];
         int i;
         int y_pages, uv_pages;
-        u8 frame = itv->yuv_info.draw_frame;
         unsigned long y_buffer_offset, uv_buffer_offset;
         int y_decode_height, uv_decode_height, y_size;
 
         y_buffer_offset = IVTV_DECODER_OFFSET + yuv_offset[frame];
         uv_buffer_offset = y_buffer_offset + IVTV_YUV_BUFFER_UV_OFFSET;
 
-        y_decode_height = uv_decode_height = args->src.height + args->src.top;
+        y_decode_height = uv_decode_height = f->src_h + f->src_x;
 
-        if (y_decode_height < 512-16)
+        if (f->offset_y)
                 y_buffer_offset += 720 * 16;
 
         if (y_decode_height & 15)
@@ -106,13 +107,11 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma,
         ivtv_udma_fill_sg_array (dma, y_buffer_offset, uv_buffer_offset, y_size);
 
         /* If we've offset the y plane, ensure top area is blanked */
-        if (args->src.height + args->src.top < 512-16) {
-                if (itv->yuv_info.blanking_dmaptr) {
-                        dma->SGarray[dma->SG_length].size = cpu_to_le32(720*16);
-                        dma->SGarray[dma->SG_length].src = cpu_to_le32(itv->yuv_info.blanking_dmaptr);
-                        dma->SGarray[dma->SG_length].dst = cpu_to_le32(IVTV_DECODER_OFFSET + yuv_offset[frame]);
-                        dma->SG_length++;
-                }
+        if (f->offset_y && itv->yuv_info.blanking_dmaptr) {
+                dma->SGarray[dma->SG_length].size = cpu_to_le32(720*16);
+                dma->SGarray[dma->SG_length].src = cpu_to_le32(itv->yuv_info.blanking_dmaptr);
+                dma->SGarray[dma->SG_length].dst = cpu_to_le32(IVTV_DECODER_OFFSET + yuv_offset[frame]);
+                dma->SG_length++;
         }
 
         /* Tag SG Array with Interrupt Bit */
@@ -387,7 +386,7 @@ static void ivtv_yuv_handle_vertical(struct ivtv *itv, struct yuv_frame_info *wi
         }
 
         /* What is the source video being treated as... */
-        if (itv->yuv_info.frame_interlaced) {
+        if (window->interlaced) {
                 IVTV_DEBUG_WARN("Source video: Interlaced\n");
         }
         else {
@@ -631,192 +630,142 @@ static void ivtv_yuv_handle_vertical(struct ivtv *itv, struct yuv_frame_info *wi
 }
 
 /* Modify the supplied coordinate information to fit the visible osd area */
-static u32 ivtv_yuv_window_setup (struct ivtv *itv, struct yuv_frame_info *window)
+static u32 ivtv_yuv_window_setup(struct ivtv *itv, struct yuv_frame_info *f)
 {
-        int osd_crop, lace_threshold;
+        struct yuv_frame_info *of = &itv->yuv_info.old_frame_info;
+        int osd_crop;
         u32 osd_scale;
         u32 yuv_update = 0;
 
-        lace_threshold = itv->yuv_info.lace_threshold;
-        if (lace_threshold < 0)
-                lace_threshold = itv->yuv_info.decode_height - 1;
-
-        /* Work out the lace settings */
-        switch (itv->yuv_info.lace_mode) {
-                case IVTV_YUV_MODE_PROGRESSIVE: /* Progressive mode */
-                        itv->yuv_info.frame_interlaced = 0;
-                        if (window->tru_h < 512 || (window->tru_h > 576 && window->tru_h < 1021))
-                                window->interlaced_y = 0;
-                        else
-                                window->interlaced_y = 1;
-
-                        if (window->tru_h < 1021 && (window->dst_h >= window->src_h /2))
-                                window->interlaced_uv = 0;
-                        else
-                                window->interlaced_uv = 1;
-                        break;
-
-                case IVTV_YUV_MODE_AUTO:
-                        if (window->tru_h <= lace_threshold || window->tru_h > 576 || window->tru_w > 720){
-                                itv->yuv_info.frame_interlaced = 0;
-                                if ((window->tru_h < 512) ||
-                                  (window->tru_h > 576 && window->tru_h < 1021) ||
-                                  (window->tru_w > 720 && window->tru_h < 1021))
-                                        window->interlaced_y = 0;
-                                else
-                                        window->interlaced_y = 1;
-
-                                if (window->tru_h < 1021 && (window->dst_h >= window->src_h /2))
-                                        window->interlaced_uv = 0;
-                                else
-                                        window->interlaced_uv = 1;
-                        }
-                        else {
-                                itv->yuv_info.frame_interlaced = 1;
-                                window->interlaced_y = 1;
-                                window->interlaced_uv = 1;
-                        }
-                        break;
-
-                        case IVTV_YUV_MODE_INTERLACED: /* Interlace mode */
-                default:
-                        itv->yuv_info.frame_interlaced = 1;
-                        window->interlaced_y = 1;
-                        window->interlaced_uv = 1;
-                        break;
-        }
-
         /* Sorry, but no negative coords for src */
-        if (window->src_x < 0) window->src_x = 0;
-        if (window->src_y < 0) window->src_y = 0;
+        if (f->src_x < 0)
+                f->src_x = 0;
+        if (f->src_y < 0)
+                f->src_y = 0;
 
         /* Can only reduce width down to 1/4 original size */
-        if ((osd_crop = window->src_w - ( 4 * window->dst_w )) > 0) {
-                window->src_x += osd_crop / 2;
-                window->src_w = (window->src_w - osd_crop) & ~3;
-                window->dst_w = window->src_w / 4;
-                window->dst_w += window->dst_w & 1;
+        if ((osd_crop = f->src_w - 4 * f->dst_w) > 0) {
+                f->src_x += osd_crop / 2;
+                f->src_w = (f->src_w - osd_crop) & ~3;
+                f->dst_w = f->src_w / 4;
+                f->dst_w += f->dst_w & 1;
         }
 
         /* Can only reduce height down to 1/4 original size */
-        if (window->src_h / window->dst_h >= 2) {
-                /* Overflow may be because we're running progressive, so force mode switch */
-                window->interlaced_y = 1;
+        if (f->src_h / f->dst_h >= 2) {
+                /* Overflow may be because we're running progressive,
+                   so force mode switch */
+                f->interlaced_y = 1;
                 /* Make sure we're still within limits for interlace */
-                if ((osd_crop = window->src_h - ( 4 * window->dst_h )) > 0) {
+                if ((osd_crop = f->src_h - 4 * f->dst_h) > 0) {
                         /* If we reach here we'll have to force the height. */
-                        window->src_y += osd_crop / 2;
-                        window->src_h = (window->src_h - osd_crop) & ~3;
-                        window->dst_h = window->src_h / 4;
-                        window->dst_h += window->dst_h & 1;
+                        f->src_y += osd_crop / 2;
+                        f->src_h = (f->src_h - osd_crop) & ~3;
+                        f->dst_h = f->src_h / 4;
+                        f->dst_h += f->dst_h & 1;
                 }
         }
 
         /* If there's nothing to safe to display, we may as well stop now */
-        if ((int)window->dst_w <= 2 || (int)window->dst_h <= 2 || (int)window->src_w <= 2 || (int)window->src_h <= 2) {
+        if ((int)f->dst_w <= 2 || (int)f->dst_h <= 2 ||
+                    (int)f->src_w <= 2 || (int)f->src_h <= 2) {
                 return IVTV_YUV_UPDATE_INVALID;
         }
 
         /* Ensure video remains inside OSD area */
-        osd_scale = (window->src_h << 16) / window->dst_h;
+        osd_scale = (f->src_h << 16) / f->dst_h;
 
-        if ((osd_crop = window->pan_y - window->dst_y) > 0) {
+        if ((osd_crop = f->pan_y - f->dst_y) > 0) {
                 /* Falls off the upper edge - crop */
-                window->src_y += (osd_scale * osd_crop) >> 16;
-                window->src_h -= (osd_scale * osd_crop) >> 16;
-                window->dst_h -= osd_crop;
-                window->dst_y = 0;
-        }
-        else {
-                window->dst_y -= window->pan_y;
+                f->src_y += (osd_scale * osd_crop) >> 16;
+                f->src_h -= (osd_scale * osd_crop) >> 16;
+                f->dst_h -= osd_crop;
+                f->dst_y = 0;
+        } else {
+                f->dst_y -= f->pan_y;
         }
 
-        if ((osd_crop = window->dst_h + window->dst_y - window->vis_h) > 0) {
+        if ((osd_crop = f->dst_h + f->dst_y - f->vis_h) > 0) {
                 /* Falls off the lower edge - crop */
-                window->dst_h -= osd_crop;
-                window->src_h -= (osd_scale * osd_crop) >> 16;
+                f->dst_h -= osd_crop;
+                f->src_h -= (osd_scale * osd_crop) >> 16;
         }
 
-        osd_scale = (window->src_w << 16) / window->dst_w;
+        osd_scale = (f->src_w << 16) / f->dst_w;
 
-        if ((osd_crop = window->pan_x - window->dst_x) > 0) {
+        if ((osd_crop = f->pan_x - f->dst_x) > 0) {
                 /* Fall off the left edge - crop */
-                window->src_x += (osd_scale * osd_crop) >> 16;
-                window->src_w -= (osd_scale * osd_crop) >> 16;
-                window->dst_w -= osd_crop;
-                window->dst_x = 0;
-        }
-        else {
-                window->dst_x -= window->pan_x;
+                f->src_x += (osd_scale * osd_crop) >> 16;
+                f->src_w -= (osd_scale * osd_crop) >> 16;
+                f->dst_w -= osd_crop;
+                f->dst_x = 0;
+        } else {
+                f->dst_x -= f->pan_x;
         }
 
-        if ((osd_crop = window->dst_w + window->dst_x - window->vis_w) > 0) {
+        if ((osd_crop = f->dst_w + f->dst_x - f->vis_w) > 0) {
                 /* Falls off the right edge - crop */
-                window->dst_w -= osd_crop;
-                window->src_w -= (osd_scale * osd_crop) >> 16;
+                f->dst_w -= osd_crop;
+                f->src_w -= (osd_scale * osd_crop) >> 16;
         }
 
         /* The OSD can be moved. Track to it */
-        window->dst_x += itv->yuv_info.osd_x_offset;
-        window->dst_y += itv->yuv_info.osd_y_offset;
+        f->dst_x += itv->yuv_info.osd_x_offset;
+        f->dst_y += itv->yuv_info.osd_y_offset;
 
         /* Width & height for both src & dst must be even.
            Same for coordinates. */
-        window->dst_w &= ~1;
-        window->dst_x &= ~1;
+        f->dst_w &= ~1;
+        f->dst_x &= ~1;
 
-        window->src_w += window->src_x & 1;
-        window->src_x &= ~1;
+        f->src_w += f->src_x & 1;
+        f->src_x &= ~1;
 
-        window->src_w &= ~1;
-        window->dst_w &= ~1;
+        f->src_w &= ~1;
+        f->dst_w &= ~1;
 
-        window->dst_h &= ~1;
-        window->dst_y &= ~1;
+        f->dst_h &= ~1;
+        f->dst_y &= ~1;
 
-        window->src_h += window->src_y & 1;
-        window->src_y &= ~1;
+        f->src_h += f->src_y & 1;
+        f->src_y &= ~1;
 
-        window->src_h &= ~1;
-        window->dst_h &= ~1;
+        f->src_h &= ~1;
+        f->dst_h &= ~1;
 
-        /* Due to rounding, we may have reduced the output size to <1/4 of the source
-           Check again, but this time just resize. Don't change source coordinates */
-        if (window->dst_w < window->src_w / 4) {
-                window->src_w &= ~3;
-                window->dst_w = window->src_w / 4;
-                window->dst_w += window->dst_w & 1;
+        /* Due to rounding, we may have reduced the output size to <1/4 of
+           the source. Check again, but this time just resize. Don't change
+           source coordinates */
+        if (f->dst_w < f->src_w / 4) {
+                f->src_w &= ~3;
+                f->dst_w = f->src_w / 4;
+                f->dst_w += f->dst_w & 1;
         }
-        if (window->dst_h < window->src_h / 4) {
-                window->src_h &= ~3;
-                window->dst_h = window->src_h / 4;
-                window->dst_h += window->dst_h & 1;
+        if (f->dst_h < f->src_h / 4) {
+                f->src_h &= ~3;
+                f->dst_h = f->src_h / 4;
+                f->dst_h += f->dst_h & 1;
         }
 
         /* Check again. If there's nothing to safe to display, stop now */
-        if ((int)window->dst_w <= 2 || (int)window->dst_h <= 2 || (int)window->src_w <= 2 || (int)window->src_h <= 2) {
+        if ((int)f->dst_w <= 2 || (int)f->dst_h <= 2 ||
+                    (int)f->src_w <= 2 || (int)f->src_h <= 2) {
                 return IVTV_YUV_UPDATE_INVALID;
         }
 
         /* Both x offset & width are linked, so they have to be done together */
-        if ((itv->yuv_info.old_frame_info.dst_w != window->dst_w) ||
-            (itv->yuv_info.old_frame_info.src_w != window->src_w) ||
-            (itv->yuv_info.old_frame_info.dst_x != window->dst_x) ||
-            (itv->yuv_info.old_frame_info.src_x != window->src_x) ||
-            (itv->yuv_info.old_frame_info.pan_x != window->pan_x) ||
-            (itv->yuv_info.old_frame_info.vis_w != window->vis_w)) {
+        if ((of->dst_w != f->dst_w) || (of->src_w != f->src_w) ||
+                    (of->dst_x != f->dst_x) || (of->src_x != f->src_x) ||
+                    (of->pan_x != f->pan_x) || (of->vis_w != f->vis_w)) {
                 yuv_update |= IVTV_YUV_UPDATE_HORIZONTAL;
         }
 
-        if ((itv->yuv_info.old_frame_info.src_h != window->src_h) ||
-            (itv->yuv_info.old_frame_info.dst_h != window->dst_h) ||
-            (itv->yuv_info.old_frame_info.dst_y != window->dst_y) ||
-            (itv->yuv_info.old_frame_info.src_y != window->src_y) ||
-            (itv->yuv_info.old_frame_info.pan_y != window->pan_y) ||
-            (itv->yuv_info.old_frame_info.vis_h != window->vis_h) ||
-            (itv->yuv_info.old_frame_info.lace_mode != window->lace_mode) ||
-            (itv->yuv_info.old_frame_info.interlaced_y != window->interlaced_y) ||
-            (itv->yuv_info.old_frame_info.interlaced_uv != window->interlaced_uv)) {
+        if ((of->src_h != f->src_h) || (of->dst_h != f->dst_h) ||
+                    (of->dst_y != f->dst_y) || (of->src_y != f->src_y) ||
+                    (of->pan_y != f->pan_y) || (of->vis_h != f->vis_h) ||
+                    (of->lace_mode != f->lace_mode) ||
+                    (of->interlaced_y != f->interlaced_y) ||
+                    (of->interlaced_uv != f->interlaced_uv)) {
                 yuv_update |= IVTV_YUV_UPDATE_VERTICAL;
         }
 
@@ -826,22 +775,22 @@ static u32 ivtv_yuv_window_setup (struct ivtv *itv, struct yuv_frame_info *windo
 /* Update the scaling register to the requested value */
 void ivtv_yuv_work_handler (struct ivtv *itv)
 {
-        struct yuv_frame_info window;
+        struct yuv_playback_info *yi = &itv->yuv_info;
+        struct yuv_frame_info f;
+        int frame = yi->update_frame;
         u32 yuv_update;
 
-        int frame = itv->yuv_info.update_frame;
-
 /*      IVTV_DEBUG_YUV("Update yuv registers for frame %d\n",frame); */
-        memcpy(&window, &itv->yuv_info.new_frame_info[frame], sizeof (window));
+        f = yi->new_frame_info[frame];
 
         /* Update the osd pan info */
-        window.pan_x = itv->yuv_info.osd_x_pan;
-        window.pan_y = itv->yuv_info.osd_y_pan;
-        window.vis_w = itv->yuv_info.osd_vis_w;
-        window.vis_h = itv->yuv_info.osd_vis_h;
+        f.pan_x = itv->yuv_info.osd_x_pan;
+        f.pan_y = itv->yuv_info.osd_y_pan;
+        f.vis_w = itv->yuv_info.osd_vis_w;
+        f.vis_h = itv->yuv_info.osd_vis_h;
 
         /* Calculate the display window coordinates. Exit if nothing left */
-        if (!(yuv_update = ivtv_yuv_window_setup (itv, &window)))
+        if (!(yuv_update = ivtv_yuv_window_setup (itv, &f)))
                 return;
 
         if (yuv_update & IVTV_YUV_UPDATE_INVALID) {
@@ -850,13 +799,12 @@ void ivtv_yuv_work_handler (struct ivtv *itv)
                 write_reg(0x00108080, 0x2898);
 
                 if (yuv_update & IVTV_YUV_UPDATE_HORIZONTAL)
-                        ivtv_yuv_handle_horizontal(itv, &window);
+                        ivtv_yuv_handle_horizontal(itv, &f);
 
                 if (yuv_update & IVTV_YUV_UPDATE_VERTICAL)
-                        ivtv_yuv_handle_vertical(itv, &window);
+                        ivtv_yuv_handle_vertical(itv, &f);
         }
-
-        memcpy(&itv->yuv_info.old_frame_info, &window, sizeof (itv->yuv_info.old_frame_info));
+        yi->old_frame_info = f;
 }
 
 static void ivtv_yuv_init (struct ivtv *itv)
@@ -986,58 +934,98 @@ void ivtv_yuv_setup_frame(struct ivtv *itv, struct ivtv_dma_frame *args)
 {
         struct yuv_playback_info *yi = &itv->yuv_info;
         u8 frame = yi->draw_frame;
+        u8 last_frame = (u8)(frame - 1) % IVTV_YUV_BUFFERS;
+        struct yuv_frame_info *nf = &yi->new_frame_info[frame];
+        struct yuv_frame_info *of = &yi->new_frame_info[last_frame];
+        int lace_threshold = yi->lace_threshold;
 
         /* Preserve old update flag in case we're overwriting a queued frame */
-        int register_update = yi->new_frame_info[frame].update;
+        int update = nf->update;
 
         /* Take a snapshot of the yuv coordinate information */
-        yi->new_frame_info[frame].src_x = args->src.left;
-        yi->new_frame_info[frame].src_y = args->src.top;
-        yi->new_frame_info[frame].src_w = args->src.width;
-        yi->new_frame_info[frame].src_h = args->src.height;
-        yi->new_frame_info[frame].dst_x = args->dst.left;
-        yi->new_frame_info[frame].dst_y = args->dst.top;
-        yi->new_frame_info[frame].dst_w = args->dst.width;
-        yi->new_frame_info[frame].dst_h = args->dst.height;
-        yi->new_frame_info[frame].tru_x = args->dst.left;
-        yi->new_frame_info[frame].tru_w = args->src_width;
-        yi->new_frame_info[frame].tru_h = args->src_height;
-
-        /* Snapshot field order */
-        yi->sync_field[frame] = yi->lace_sync_field;
+        nf->src_x = args->src.left;
+        nf->src_y = args->src.top;
+        nf->src_w = args->src.width;
+        nf->src_h = args->src.height;
+        nf->dst_x = args->dst.left;
+        nf->dst_y = args->dst.top;
+        nf->dst_w = args->dst.width;
+        nf->dst_h = args->dst.height;
+        nf->tru_x = args->dst.left;
+        nf->tru_w = args->src_width;
+        nf->tru_h = args->src_height;
 
         /* Are we going to offset the Y plane */
-        if (args->src.height + args->src.top < 512-16)
-                yi->new_frame_info[frame].offset_y = 1;
-        else
-                yi->new_frame_info[frame].offset_y = 0;
+        nf->offset_y = (nf->tru_h + nf->src_x < 512 - 16) ? 1 : 0;
 
         /* Snapshot the osd pan info */
-        yi->new_frame_info[frame].pan_x = yi->osd_x_pan;
-        yi->new_frame_info[frame].pan_y = yi->osd_y_pan;
-        yi->new_frame_info[frame].vis_w = yi->osd_vis_w;
-        yi->new_frame_info[frame].vis_h = yi->osd_vis_h;
-
-        yi->new_frame_info[frame].update = 0;
-        yi->new_frame_info[frame].interlaced_y = 0;
-        yi->new_frame_info[frame].interlaced_uv = 0;
-        yi->new_frame_info[frame].lace_mode = yi->lace_mode & IVTV_YUV_MODE_MASK;
-
-        if (memcmp(&yi->old_frame_info_args, &yi->new_frame_info[frame],
-                                        sizeof(yi->new_frame_info[frame]))) {
-                yi->old_frame_info_args = yi->new_frame_info[frame];
-                yi->new_frame_info[frame].update = 1;
-/* IVTV_DEBUG_YUV ("Requesting register update for frame %d\n",frame); */
+        nf->pan_x = yi->osd_x_pan;
+        nf->pan_y = yi->osd_y_pan;
+        nf->vis_w = yi->osd_vis_w;
+        nf->vis_h = yi->osd_vis_h;
+
+        nf->update = 0;
+        nf->interlaced_y = 0;
+        nf->interlaced_uv = 0;
+        nf->delay = 0;
+        nf->sync_field = 0;
+        nf->lace_mode = yi->lace_mode & IVTV_YUV_MODE_MASK;
+
+        if (lace_threshold < 0)
+                lace_threshold = yi->decode_height - 1;
+
+        /* Work out the lace settings */
+        switch (nf->lace_mode) {
+        case IVTV_YUV_MODE_PROGRESSIVE: /* Progressive mode */
+                nf->interlaced = 0;
+                if (nf->tru_h < 512 || (nf->tru_h > 576 && nf->tru_h < 1021))
+                        nf->interlaced_y = 0;
+                else
+                        nf->interlaced_y = 1;
+
+                if (nf->tru_h < 1021 && (nf->dst_h >= nf->src_h / 2))
+                        nf->interlaced_uv = 0;
+                else
+                        nf->interlaced_uv = 1;
+                break;
+
+        case IVTV_YUV_MODE_AUTO:
+                if (nf->tru_h <= lace_threshold || nf->tru_h > 576 || nf->tru_w > 720) {
+                        nf->interlaced = 0;
+                        if ((nf->tru_h < 512) ||
+                                 (nf->tru_h > 576 && nf->tru_h < 1021) ||
+                                 (nf->tru_w > 720 && nf->tru_h < 1021))
+                                nf->interlaced_y = 0;
+                        else
+                                nf->interlaced_y = 1;
+                        if (nf->tru_h < 1021 && (nf->dst_h >= nf->src_h / 2))
+                                nf->interlaced_uv = 0;
+                        else
+                                nf->interlaced_uv = 1;
+                } else {
+                        nf->interlaced = 1;
+                        nf->interlaced_y = 1;
+                        nf->interlaced_uv = 1;
+                }
+                break;
+
+        case IVTV_YUV_MODE_INTERLACED: /* Interlace mode */
+        default:
+                nf->interlaced = 1;
+                nf->interlaced_y = 1;
+                nf->interlaced_uv = 1;
+                break;
         }
 
-        yi->new_frame_info[frame].update |= register_update;
+        if (memcmp(&yi->old_frame_info_args, nf, sizeof(*nf))) {
+                yi->old_frame_info_args = *nf;
+                nf->update = 1;
+/* IVTV_DEBUG_YUV ("Requesting register update for frame %d\n",frame); */
+        }
 
-        /* Should this frame be delayed ? */
-        if (yi->sync_field[frame] !=
-                                yi->sync_field[(frame - 1) % IVTV_YUV_BUFFERS])
-                yi->field_delay[frame] = 1;
-        else
-                yi->field_delay[frame] = 0;
+        nf->update |= update;
+        nf->sync_field = yi->lace_sync_field;
+        nf->delay = nf->sync_field != of->sync_field;
 }
 
 /* Frame is complete & ready for display */