If bt timing has REDUCED_FPS flag set, then reduce the frame rate
by factor of 1000 / 1001. For vivid, timeperframe_vid_out indicates
the frame timings used by video out thread. The timeperframe_vid_out
is derived from pixel clock. Adjusting the timeperframe_vid_out by
scaling down pixel clock with factor of 1000 / 1001.
The reduced fps is supported for CVT timings if reduced blanking v2
(indicated by vsync = 8) is true. For CEA861 timings, reduced fps is
supported if V4L2_DV_FL_CAN_REDUCE_FPS flag is true. For GTF timings,
reduced fps is not supported.
The reduced fps will allow refresh rates like 29.97, 59.94 etc.
Cc: Hans Verkuil <hans.verk...@cisco.com>
Signed-off-by: Prashant Laddha <prlad...@cisco.com>
---
drivers/media/platform/vivid/vivid-vid-out.c | 30 +++++++++++++++++++++++++++-
drivers/media/v4l2-core/v4l2-dv-timings.c | 5 +++++
2 files changed, 34 insertions(+), 1 deletion(-)
diff --git a/drivers/media/platform/vivid/vivid-vid-out.c
b/drivers/media/platform/vivid/vivid-vid-out.c
index c404e27..ca6ec78 100644
--- a/drivers/media/platform/vivid/vivid-vid-out.c
+++ b/drivers/media/platform/vivid/vivid-vid-out.c
@@ -213,6 +213,27 @@ const struct vb2_ops vivid_vid_out_qops = {
};
/*
+ * Called to check conditions for reduced fps. For CVT timings, reduced
+ * fps is allowed only with reduced blanking v2 (vsync == 8). For CEA861
+ * timings, reduced fps is allowed if V4L2_DV_FL_CAN_REDUCE_FPS flag is
+ * true.
+ */
+static bool reduce_fps(struct v4l2_bt_timings *bt)
+{
+ if (!(bt->flags & V4L2_DV_FL_REDUCED_FPS))
+ return false;
+
+ if ((bt->standards & V4L2_DV_BT_STD_CVT) && (bt->vsync == 8))
+ return true;
+
+ if ((bt->standards & V4L2_DV_BT_STD_CEA861) &&
+ (bt->flags & V4L2_DV_FL_CAN_REDUCE_FPS))
+ return true;
+
+ return false;
+}
+
+/*
* Called whenever the format has to be reset which can occur when
* changing outputs, standard, timings, etc.
*/
@@ -220,6 +241,7 @@ void vivid_update_format_out(struct vivid_dev *dev)
{
struct v4l2_bt_timings *bt = &dev->dv_timings_out.bt;
unsigned size, p;
+ u64 pixelclock;
switch (dev->output_type[dev->output]) {
case SVID:
@@ -241,8 +263,14 @@ void vivid_update_format_out(struct vivid_dev *dev)
dev->sink_rect.width = bt->width;
dev->sink_rect.height = bt->height;
size = V4L2_DV_BT_FRAME_WIDTH(bt) * V4L2_DV_BT_FRAME_HEIGHT(bt);
+
+ if (reduce_fps(bt))
+ pixelclock = div_u64((bt->pixelclock * 1000), 1001);
+ else
+ pixelclock = bt->pixelclock;
+
dev->timeperframe_vid_out = (struct v4l2_fract) {
- size / 100, (u32)bt->pixelclock / 100
+ size / 100, (u32)pixelclock / 100
};
if (bt->interlaced)
dev->field_out = V4L2_FIELD_ALTERNATE;
diff --git a/drivers/media/v4l2-core/v4l2-dv-timings.c
b/drivers/media/v4l2-core/v4l2-dv-timings.c
index 6a83d61..adc03bd 100644
--- a/drivers/media/v4l2-core/v4l2-dv-timings.c
+++ b/drivers/media/v4l2-core/v4l2-dv-timings.c
@@ -210,7 +210,12 @@ bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings *t,
fnc, fnc_handle) &&
v4l2_match_dv_timings(t, v4l2_dv_timings_presets + i,
pclock_delta)) {
+ u32 flags = t->bt.flags & V4L2_DV_FL_REDUCED_FPS;
+
*t = v4l2_dv_timings_presets[i];
+ if (t->bt.flags & V4L2_DV_FL_CAN_REDUCE_FPS)
+ t->bt.flags |= flags;
+
return true;
}
}
--
1.9.1
--
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