[media] vivid: add the kthread code that controls the video rate

Add the kthread handlers for video/vbi capture and video/vbi output.
These carefully control the rate at which frames are generated (video
capture) and accepted (video output). While the short-term jitter is
around the order of a jiffie, in the long term the rate matches the
configured framerate exactly.

The capture thread handler also takes care of the video looping and
of capture and overlay support. This is probably the most complex part
of this driver due to the many combinations of crop, compose and scaling
on the input and output, and the blending that has to be done if
overlay support is enabled as well.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/platform/vivid/vivid-kthread-cap.c

+/*
+ * vivid-kthread-cap.h - video/vbi capture thread support functions.
+ *
+ * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/font.h>
+#include <linux/mutex.h>
+#include <linux/videodev2.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/random.h>
+#include <linux/v4l2-dv-timings.h>
+#include <asm/div64.h>
+#include <media/videobuf2-vmalloc.h>
+#include <media/v4l2-dv-timings.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-fh.h>
+#include <media/v4l2-event.h>
+
+#include "vivid-core.h"
+#include "vivid-vid-common.h"
+#include "vivid-vid-cap.h"
+#include "vivid-vid-out.h"
+#include "vivid-radio-common.h"
+#include "vivid-radio-rx.h"
+#include "vivid-radio-tx.h"
+#include "vivid-sdr-cap.h"
+#include "vivid-vbi-cap.h"
+#include "vivid-vbi-out.h"
+#include "vivid-osd.h"
+#include "vivid-ctrls.h"
+
+static inline v4l2_std_id vivid_get_std_cap(const struct vivid_dev *dev)
+{
+	if (vivid_is_sdtv_cap(dev))
+		return dev->std_cap;
+	return 0;
+}
+
+static void copy_pix(struct vivid_dev *dev, int win_y, int win_x,
+			u16 *cap, const u16 *osd)
+{
+	u16 out;
+	int left = dev->overlay_out_left;
+	int top = dev->overlay_out_top;
+	int fb_x = win_x + left;
+	int fb_y = win_y + top;
+	int i;
+
+	out = *cap;
+	*cap = *osd;
+	if (dev->bitmap_out) {
+		const u8 *p = dev->bitmap_out;
+		unsigned stride = (dev->compose_out.width + 7) / 8;
+
+		win_x -= dev->compose_out.left;
+		win_y -= dev->compose_out.top;
+		if (!(p[stride * win_y + win_x / 8] & (1 << (win_x & 7))))
+			return;
+	}
+
+	for (i = 0; i < dev->clipcount_out; i++) {
+		struct v4l2_rect *r = &dev->clips_out[i].c;
+
+		if (fb_y >= r->top && fb_y < r->top + r->height &&
+		    fb_x >= r->left && fb_x < r->left + r->width)
+			return;
+	}
+	if ((dev->fbuf_out_flags & V4L2_FBUF_FLAG_CHROMAKEY) &&
+	    *osd != dev->chromakey_out)
+		return;
+	if ((dev->fbuf_out_flags & V4L2_FBUF_FLAG_SRC_CHROMAKEY) &&
+	    out == dev->chromakey_out)
+		return;
+	if (dev->fmt_cap->alpha_mask) {
+		if ((dev->fbuf_out_flags & V4L2_FBUF_FLAG_GLOBAL_ALPHA) &&
+		    dev->global_alpha_out)
+			return;
+		if ((dev->fbuf_out_flags & V4L2_FBUF_FLAG_LOCAL_ALPHA) &&
+		    *cap & dev->fmt_cap->alpha_mask)
+			return;
+		if ((dev->fbuf_out_flags & V4L2_FBUF_FLAG_LOCAL_INV_ALPHA) &&
+		    !(*cap & dev->fmt_cap->alpha_mask))
+			return;
+	}
+	*cap = out;
+}
+
+static void blend_line(struct vivid_dev *dev, unsigned y_offset, unsigned x_offset,
+		u8 *vcapbuf, const u8 *vosdbuf,
+		unsigned width, unsigned pixsize)
+{
+	unsigned x;
+
+	for (x = 0; x < width; x++, vcapbuf += pixsize, vosdbuf += pixsize) {
+		copy_pix(dev, y_offset, x_offset + x,
+			 (u16 *)vcapbuf, (const u16 *)vosdbuf);
+	}
+}
+
+static void scale_line(const u8 *src, u8 *dst, unsigned srcw, unsigned dstw, unsigned twopixsize)
+{
+	/* Coarse scaling with Bresenham */
+	unsigned int_part;
+	unsigned fract_part;
+	unsigned src_x = 0;
+	unsigned error = 0;
+	unsigned x;
+
+	/*
+	 * We always combine two pixels to prevent color bleed in the packed
+	 * yuv case.
+	 */
+	srcw /= 2;
+	dstw /= 2;
+	int_part = srcw / dstw;
+	fract_part = srcw % dstw;
+	for (x = 0; x < dstw; x++, dst += twopixsize) {
+		memcpy(dst, src + src_x * twopixsize, twopixsize);
+		src_x += int_part;
+		error += fract_part;
+		if (error >= dstw) {
+			error -= dstw;
+			src_x++;
+		}
+	}
+}
+
+/*
+ * Precalculate the rectangles needed to perform video looping:
+ *
+ * The nominal pipeline is that the video output buffer is cropped by
+ * crop_out, scaled to compose_out, overlaid with the output overlay,
+ * cropped on the capture side by crop_cap and scaled again to the video
+ * capture buffer using compose_cap.
+ *
+ * To keep things efficient we calculate the intersection of compose_out
+ * and crop_cap (since that's the only part of the video that will
+ * actually end up in the capture buffer), determine which part of the
+ * video output buffer that is and which part of the video capture buffer
+ * so we can scale the video straight from the output buffer to the capture
+ * buffer without any intermediate steps.
+ *
+ * If we need to deal with an output overlay, then there is no choice and
+ * that intermediate step still has to be taken. For the output overlay
+ * support we calculate the intersection of the framebuffer and the overlay
+ * window (which may be partially or wholly outside of the framebuffer
+ * itself) and the intersection of that with loop_vid_copy (i.e. the part of
+ * the actual looped video that will be overlaid). The result is calculated
+ * both in framebuffer coordinates (loop_fb_copy) and compose_out coordinates
+ * (loop_vid_overlay). Finally calculate the part of the capture buffer that
+ * will receive that overlaid video.
+ */
+static void vivid_precalc_copy_rects(struct vivid_dev *dev)
+{
+	/* Framebuffer rectangle */
+	struct v4l2_rect r_fb = {
+		0, 0, dev->display_width, dev->display_height
+	};
+	/* Overlay window rectangle in framebuffer coordinates */
+	struct v4l2_rect r_overlay = {
+		dev->overlay_out_left, dev->overlay_out_top,
+		dev->compose_out.width, dev->compose_out.height
+	};
+
+	dev->loop_vid_copy = rect_intersect(&dev->crop_cap, &dev->compose_out);
+
+	dev->loop_vid_out = dev->loop_vid_copy;
+	rect_scale(&dev->loop_vid_out, &dev->compose_out, &dev->crop_out);
+	dev->loop_vid_out.left += dev->crop_out.left;
+	dev->loop_vid_out.top += dev->crop_out.top;
+
+	dev->loop_vid_cap = dev->loop_vid_copy;
+	rect_scale(&dev->loop_vid_cap, &dev->crop_cap, &dev->compose_cap);
+
+	dprintk(dev, 1,
+		"loop_vid_copy: %dx%d@%dx%d loop_vid_out: %dx%d@%dx%d loop_vid_cap: %dx%d@%dx%d\n",
+		dev->loop_vid_copy.width, dev->loop_vid_copy.height,
+		dev->loop_vid_copy.left, dev->loop_vid_copy.top,
+		dev->loop_vid_out.width, dev->loop_vid_out.height,
+		dev->loop_vid_out.left, dev->loop_vid_out.top,
+		dev->loop_vid_cap.width, dev->loop_vid_cap.height,
+		dev->loop_vid_cap.left, dev->loop_vid_cap.top);
+
+	r_overlay = rect_intersect(&r_fb, &r_overlay);
+
+	/* shift r_overlay to the same origin as compose_out */
+	r_overlay.left += dev->compose_out.left - dev->overlay_out_left;
+	r_overlay.top += dev->compose_out.top - dev->overlay_out_top;
+
+	dev->loop_vid_overlay = rect_intersect(&r_overlay, &dev->loop_vid_copy);
+	dev->loop_fb_copy = dev->loop_vid_overlay;
+
+	/* shift dev->loop_fb_copy back again to the fb origin */
+	dev->loop_fb_copy.left -= dev->compose_out.left - dev->overlay_out_left;
+	dev->loop_fb_copy.top -= dev->compose_out.top - dev->overlay_out_top;
+
+	dev->loop_vid_overlay_cap = dev->loop_vid_overlay;
+	rect_scale(&dev->loop_vid_overlay_cap, &dev->crop_cap, &dev->compose_cap);
+
+	dprintk(dev, 1,
+		"loop_fb_copy: %dx%d@%dx%d loop_vid_overlay: %dx%d@%dx%d loop_vid_overlay_cap: %dx%d@%dx%d\n",
+		dev->loop_fb_copy.width, dev->loop_fb_copy.height,
+		dev->loop_fb_copy.left, dev->loop_fb_copy.top,
+		dev->loop_vid_overlay.width, dev->loop_vid_overlay.height,
+		dev->loop_vid_overlay.left, dev->loop_vid_overlay.top,
+		dev->loop_vid_overlay_cap.width, dev->loop_vid_overlay_cap.height,
+		dev->loop_vid_overlay_cap.left, dev->loop_vid_overlay_cap.top);
+}
+
+static int vivid_copy_buffer(struct vivid_dev *dev, unsigned p, u8 *vcapbuf,
+		struct vivid_buffer *vid_cap_buf)
+{
+	bool blank = dev->must_blank[vid_cap_buf->vb.v4l2_buf.index];
+	struct tpg_data *tpg = &dev->tpg;
+	struct vivid_buffer *vid_out_buf = NULL;
+	unsigned pixsize = tpg_g_twopixelsize(tpg, p) / 2;
+	unsigned img_width = dev->compose_cap.width;
+	unsigned img_height = dev->compose_cap.height;
+	unsigned stride_cap = tpg->bytesperline[p];
+	unsigned stride_out = dev->bytesperline_out[p];
+	unsigned stride_osd = dev->display_byte_stride;
+	unsigned hmax = (img_height * tpg->perc_fill) / 100;
+	u8 *voutbuf;
+	u8 *vosdbuf = NULL;
+	unsigned y;
+	bool blend = dev->bitmap_out || dev->clipcount_out || dev->fbuf_out_flags;
+	/* Coarse scaling with Bresenham */
+	unsigned vid_out_int_part;
+	unsigned vid_out_fract_part;
+	unsigned vid_out_y = 0;
+	unsigned vid_out_error = 0;
+	unsigned vid_overlay_int_part = 0;
+	unsigned vid_overlay_fract_part = 0;
+	unsigned vid_overlay_y = 0;
+	unsigned vid_overlay_error = 0;
+	unsigned vid_cap_right;
+	bool quick;
+
+	vid_out_int_part = dev->loop_vid_out.height / dev->loop_vid_cap.height;
+	vid_out_fract_part = dev->loop_vid_out.height % dev->loop_vid_cap.height;
+
+	if (!list_empty(&dev->vid_out_active))
+		vid_out_buf = list_entry(dev->vid_out_active.next,
+					 struct vivid_buffer, list);
+	if (vid_out_buf == NULL)
+		return -ENODATA;
+
+	vid_cap_buf->vb.v4l2_buf.field = vid_out_buf->vb.v4l2_buf.field;
+
+	voutbuf = vb2_plane_vaddr(&vid_out_buf->vb, p) +
+				  vid_out_buf->vb.v4l2_planes[p].data_offset;
+	voutbuf += dev->loop_vid_out.left * pixsize + dev->loop_vid_out.top * stride_out;
+	vcapbuf += dev->compose_cap.left * pixsize + dev->compose_cap.top * stride_cap;
+
+	if (dev->loop_vid_copy.width == 0 || dev->loop_vid_copy.height == 0) {
+		/*
+		 * If there is nothing to copy, then just fill the capture window
+		 * with black.
+		 */
+		for (y = 0; y < hmax; y++, vcapbuf += stride_cap)
+			memcpy(vcapbuf, tpg->black_line[p], img_width * pixsize);
+		return 0;
+	}
+
+	if (dev->overlay_out_enabled &&
+	    dev->loop_vid_overlay.width && dev->loop_vid_overlay.height) {
+		vosdbuf = dev->video_vbase;
+		vosdbuf += dev->loop_fb_copy.left * pixsize +
+			   dev->loop_fb_copy.top * stride_osd;
+		vid_overlay_int_part = dev->loop_vid_overlay.height /
+				       dev->loop_vid_overlay_cap.height;
+		vid_overlay_fract_part = dev->loop_vid_overlay.height %
+					 dev->loop_vid_overlay_cap.height;
+	}
+
+	vid_cap_right = dev->loop_vid_cap.left + dev->loop_vid_cap.width;
+	/* quick is true if no video scaling is needed */
+	quick = dev->loop_vid_out.width == dev->loop_vid_cap.width;
+
+	dev->cur_scaled_line = dev->loop_vid_out.height;
+	for (y = 0; y < hmax; y++, vcapbuf += stride_cap) {
+		/* osdline is true if this line requires overlay blending */
+		bool osdline = vosdbuf && y >= dev->loop_vid_overlay_cap.top &&
+			  y < dev->loop_vid_overlay_cap.top + dev->loop_vid_overlay_cap.height;
+
+		/*
+		 * If this line of the capture buffer doesn't get any video, then
+		 * just fill with black.
+		 */
+		if (y < dev->loop_vid_cap.top ||
+		    y >= dev->loop_vid_cap.top + dev->loop_vid_cap.height) {
+			memcpy(vcapbuf, tpg->black_line[p], img_width * pixsize);
+			continue;
+		}
+
+		/* fill the left border with black */
+		if (dev->loop_vid_cap.left)
+			memcpy(vcapbuf, tpg->black_line[p], dev->loop_vid_cap.left * pixsize);
+
+		/* fill the right border with black */
+		if (vid_cap_right < img_width)
+			memcpy(vcapbuf + vid_cap_right * pixsize,
+				tpg->black_line[p], (img_width - vid_cap_right) * pixsize);
+
+		if (quick && !osdline) {
+			memcpy(vcapbuf + dev->loop_vid_cap.left * pixsize,
+			       voutbuf + vid_out_y * stride_out,
+			       dev->loop_vid_cap.width * pixsize);
+			goto update_vid_out_y;
+		}
+		if (dev->cur_scaled_line == vid_out_y) {
+			memcpy(vcapbuf + dev->loop_vid_cap.left * pixsize,
+			       dev->scaled_line,
+			       dev->loop_vid_cap.width * pixsize);
+			goto update_vid_out_y;
+		}
+		if (!osdline) {
+			scale_line(voutbuf + vid_out_y * stride_out, dev->scaled_line,
+				dev->loop_vid_out.width, dev->loop_vid_cap.width,
+				tpg_g_twopixelsize(tpg, p));
+		} else {
+			/*
+			 * Offset in bytes within loop_vid_copy to the start of the
+			 * loop_vid_overlay rectangle.
+			 */
+			unsigned offset =
+				(dev->loop_vid_overlay.left - dev->loop_vid_copy.left) * pixsize;
+			u8 *osd = vosdbuf + vid_overlay_y * stride_osd;
+
+			scale_line(voutbuf + vid_out_y * stride_out, dev->blended_line,
+				dev->loop_vid_out.width, dev->loop_vid_copy.width,
+				tpg_g_twopixelsize(tpg, p));
+			if (blend)
+				blend_line(dev, vid_overlay_y + dev->loop_vid_overlay.top,
+					   dev->loop_vid_overlay.left,
+					   dev->blended_line + offset, osd,
+					   dev->loop_vid_overlay.width, pixsize);
+			else
+				memcpy(dev->blended_line + offset,
+				       osd, dev->loop_vid_overlay.width * pixsize);
+			scale_line(dev->blended_line, dev->scaled_line,
+					dev->loop_vid_copy.width, dev->loop_vid_cap.width,
+					tpg_g_twopixelsize(tpg, p));
+		}
+		dev->cur_scaled_line = vid_out_y;
+		memcpy(vcapbuf + dev->loop_vid_cap.left * pixsize,
+		       dev->scaled_line,
+		       dev->loop_vid_cap.width * pixsize);
+
+update_vid_out_y:
+		if (osdline) {
+			vid_overlay_y += vid_overlay_int_part;
+			vid_overlay_error += vid_overlay_fract_part;
+			if (vid_overlay_error >= dev->loop_vid_overlay_cap.height) {
+				vid_overlay_error -= dev->loop_vid_overlay_cap.height;
+				vid_overlay_y++;
+			}
+		}
+		vid_out_y += vid_out_int_part;
+		vid_out_error += vid_out_fract_part;
+		if (vid_out_error >= dev->loop_vid_cap.height) {
+			vid_out_error -= dev->loop_vid_cap.height;
+			vid_out_y++;
+		}
+	}
+
+	if (!blank)
+		return 0;
+	for (; y < img_height; y++, vcapbuf += stride_cap)
+		memcpy(vcapbuf, tpg->contrast_line[p], img_width * pixsize);
+	return 0;
+}
+
+static void vivid_fillbuff(struct vivid_dev *dev, struct vivid_buffer *buf)
+{
+	unsigned factor = V4L2_FIELD_HAS_T_OR_B(dev->field_cap) ? 2 : 1;
+	unsigned line_height = 16 / factor;
+	bool is_tv = vivid_is_sdtv_cap(dev);
+	bool is_60hz = is_tv && (dev->std_cap & V4L2_STD_525_60);
+	unsigned p;
+	int line = 1;
+	u8 *basep[TPG_MAX_PLANES][2];
+	unsigned ms;
+	char str[100];
+	s32 gain;
+	bool is_loop = false;
+
+	if (dev->loop_video && dev->can_loop_video &&
+	    ((vivid_is_svid_cap(dev) && !VIVID_INVALID_SIGNAL(dev->std_signal_mode)) ||
+	     (vivid_is_hdmi_cap(dev) && !VIVID_INVALID_SIGNAL(dev->dv_timings_signal_mode))))
+		is_loop = true;
+
+	buf->vb.v4l2_buf.sequence = dev->vid_cap_seq_count;
+	/*
+	 * Take the timestamp now if the timestamp source is set to
+	 * "Start of Exposure".
+	 */
+	if (dev->tstamp_src_is_soe)
+		v4l2_get_timestamp(&buf->vb.v4l2_buf.timestamp);
+	if (dev->field_cap == V4L2_FIELD_ALTERNATE) {
+		/*
+		 * 60 Hz standards start with the bottom field, 50 Hz standards
+		 * with the top field. So if the 0-based seq_count is even,
+		 * then the field is TOP for 50 Hz and BOTTOM for 60 Hz
+		 * standards.
+		 */
+		buf->vb.v4l2_buf.field = ((dev->vid_cap_seq_count & 1) ^ is_60hz) ?
+			V4L2_FIELD_TOP : V4L2_FIELD_BOTTOM;
+		/*
+		 * The sequence counter counts frames, not fields. So divide
+		 * by two.
+		 */
+		buf->vb.v4l2_buf.sequence /= 2;
+	} else {
+		buf->vb.v4l2_buf.field = dev->field_cap;
+	}
+	tpg_s_field(&dev->tpg, buf->vb.v4l2_buf.field);
+	tpg_s_perc_fill_blank(&dev->tpg, dev->must_blank[buf->vb.v4l2_buf.index]);
+
+	vivid_precalc_copy_rects(dev);
+
+	for (p = 0; p < tpg_g_planes(&dev->tpg); p++) {
+		void *vbuf = vb2_plane_vaddr(&buf->vb, p);
+
+		/*
+		 * The first plane of a multiplanar format has a non-zero
+		 * data_offset. This helps testing whether the application
+		 * correctly supports non-zero data offsets.
+		 */
+		if (dev->fmt_cap->data_offset[p]) {
+			memset(vbuf, dev->fmt_cap->data_offset[p] & 0xff,
+			       dev->fmt_cap->data_offset[p]);
+			vbuf += dev->fmt_cap->data_offset[p];
+		}
+		tpg_calc_text_basep(&dev->tpg, basep, p, vbuf);
+		if (!is_loop || vivid_copy_buffer(dev, p, vbuf, buf))
+			tpg_fillbuffer(&dev->tpg, vivid_get_std_cap(dev), p, vbuf);
+	}
+	dev->must_blank[buf->vb.v4l2_buf.index] = false;
+
+	/* Updates stream time, only update at the start of a new frame. */
+	if (dev->field_cap != V4L2_FIELD_ALTERNATE || (buf->vb.v4l2_buf.sequence & 1) == 0)
+		dev->ms_vid_cap = jiffies_to_msecs(jiffies - dev->jiffies_vid_cap);
+
+	ms = dev->ms_vid_cap;
+	if (dev->osd_mode <= 1) {
+		snprintf(str, sizeof(str), " %02d:%02d:%02d:%03d %u%s",
+				(ms / (60 * 60 * 1000)) % 24,
+				(ms / (60 * 1000)) % 60,
+				(ms / 1000) % 60,
+				ms % 1000,
+				buf->vb.v4l2_buf.sequence,
+				(dev->field_cap == V4L2_FIELD_ALTERNATE) ?
+					(buf->vb.v4l2_buf.field == V4L2_FIELD_TOP ?
+					 " top" : " bottom") : "");
+		tpg_gen_text(&dev->tpg, basep, line++ * line_height, 16, str);
+	}
+	if (dev->osd_mode == 0) {
+		snprintf(str, sizeof(str), " %dx%d, input %d ",
+				dev->src_rect.width, dev->src_rect.height, dev->input);
+		tpg_gen_text(&dev->tpg, basep, line++ * line_height, 16, str);
+
+		gain = v4l2_ctrl_g_ctrl(dev->gain);
+		mutex_lock(dev->ctrl_hdl_user_vid.lock);
+		snprintf(str, sizeof(str),
+			" brightness %3d, contrast %3d, saturation %3d, hue %d ",
+			dev->brightness->cur.val,
+			dev->contrast->cur.val,
+			dev->saturation->cur.val,
+			dev->hue->cur.val);
+		tpg_gen_text(&dev->tpg, basep, line++ * line_height, 16, str);
+		snprintf(str, sizeof(str),
+			" autogain %d, gain %3d, alpha 0x%02x ",
+			dev->autogain->cur.val, gain, dev->alpha->cur.val);
+		mutex_unlock(dev->ctrl_hdl_user_vid.lock);
+		tpg_gen_text(&dev->tpg, basep, line++ * line_height, 16, str);
+		mutex_lock(dev->ctrl_hdl_user_aud.lock);
+		snprintf(str, sizeof(str),
+			" volume %3d, mute %d ",
+			dev->volume->cur.val, dev->mute->cur.val);
+		mutex_unlock(dev->ctrl_hdl_user_aud.lock);
+		tpg_gen_text(&dev->tpg, basep, line++ * line_height, 16, str);
+		mutex_lock(dev->ctrl_hdl_user_gen.lock);
+		snprintf(str, sizeof(str), " int32 %d, int64 %lld, bitmask %08x ",
+			dev->int32->cur.val,
+			*dev->int64->p_cur.p_s64,
+			dev->bitmask->cur.val);
+		tpg_gen_text(&dev->tpg, basep, line++ * line_height, 16, str);
+		snprintf(str, sizeof(str), " boolean %d, menu %s, string \"%s\" ",
+			dev->boolean->cur.val,
+			dev->menu->qmenu[dev->menu->cur.val],
+			dev->string->p_cur.p_char);
+		tpg_gen_text(&dev->tpg, basep, line++ * line_height, 16, str);
+		snprintf(str, sizeof(str), " integer_menu %lld, value %d ",
+			dev->int_menu->qmenu_int[dev->int_menu->cur.val],
+			dev->int_menu->cur.val);
+		mutex_unlock(dev->ctrl_hdl_user_gen.lock);
+		tpg_gen_text(&dev->tpg, basep, line++ * line_height, 16, str);
+		if (dev->button_pressed) {
+			dev->button_pressed--;
+			snprintf(str, sizeof(str), " button pressed!");
+			tpg_gen_text(&dev->tpg, basep, line++ * line_height, 16, str);
+		}
+	}
+
+	/*
+	 * If "End of Frame" is specified at the timestamp source, then take
+	 * the timestamp now.
+	 */
+	if (!dev->tstamp_src_is_soe)
+		v4l2_get_timestamp(&buf->vb.v4l2_buf.timestamp);
+	buf->vb.v4l2_buf.timestamp.tv_sec += dev->time_wrap_offset;
+}
+
+/*
+ * Return true if this pixel coordinate is a valid video pixel.
+ */
+static bool valid_pix(struct vivid_dev *dev, int win_y, int win_x, int fb_y, int fb_x)
+{
+	int i;
+
+	if (dev->bitmap_cap) {
+		/*
+		 * Only if the corresponding bit in the bitmap is set can
+		 * the video pixel be shown. Coordinates are relative to
+		 * the overlay window set by VIDIOC_S_FMT.
+		 */
+		const u8 *p = dev->bitmap_cap;
+		unsigned stride = (dev->compose_cap.width + 7) / 8;
+
+		if (!(p[stride * win_y + win_x / 8] & (1 << (win_x & 7))))
+			return false;
+	}
+
+	for (i = 0; i < dev->clipcount_cap; i++) {
+		/*
+		 * Only if the framebuffer coordinate is not in any of the
+		 * clip rectangles will be video pixel be shown.
+		 */
+		struct v4l2_rect *r = &dev->clips_cap[i].c;
+
+		if (fb_y >= r->top && fb_y < r->top + r->height &&
+		    fb_x >= r->left && fb_x < r->left + r->width)
+			return false;
+	}
+	return true;
+}
+
+/*
+ * Draw the image into the overlay buffer.
+ * Note that the combination of overlay and multiplanar is not supported.
+ */
+static void vivid_overlay(struct vivid_dev *dev, struct vivid_buffer *buf)
+{
+	struct tpg_data *tpg = &dev->tpg;
+	unsigned pixsize = tpg_g_twopixelsize(tpg, 0) / 2;
+	void *vbase = dev->fb_vbase_cap;
+	void *vbuf = vb2_plane_vaddr(&buf->vb, 0);
+	unsigned img_width = dev->compose_cap.width;
+	unsigned img_height = dev->compose_cap.height;
+	unsigned stride = tpg->bytesperline[0];
+	/* if quick is true, then valid_pix() doesn't have to be called */
+	bool quick = dev->bitmap_cap == NULL && dev->clipcount_cap == 0;
+	int x, y, w, out_x = 0;
+
+	if ((dev->overlay_cap_field == V4L2_FIELD_TOP ||
+	     dev->overlay_cap_field == V4L2_FIELD_BOTTOM) &&
+	    dev->overlay_cap_field != buf->vb.v4l2_buf.field)
+		return;
+
+	vbuf += dev->compose_cap.left * pixsize + dev->compose_cap.top * stride;
+	x = dev->overlay_cap_left;
+	w = img_width;
+	if (x < 0) {
+		out_x = -x;
+		w = w - out_x;
+		x = 0;
+	} else {
+		w = dev->fb_cap.fmt.width - x;
+		if (w > img_width)
+			w = img_width;
+	}
+	if (w <= 0)
+		return;
+	if (dev->overlay_cap_top >= 0)
+		vbase += dev->overlay_cap_top * dev->fb_cap.fmt.bytesperline;
+	for (y = dev->overlay_cap_top;
+	     y < dev->overlay_cap_top + (int)img_height;
+	     y++, vbuf += stride) {
+		int px;
+
+		if (y < 0 || y > dev->fb_cap.fmt.height)
+			continue;
+		if (quick) {
+			memcpy(vbase + x * pixsize,
+			       vbuf + out_x * pixsize, w * pixsize);
+			vbase += dev->fb_cap.fmt.bytesperline;
+			continue;
+		}
+		for (px = 0; px < w; px++) {
+			if (!valid_pix(dev, y - dev->overlay_cap_top,
+				       px + out_x, y, px + x))
+				continue;
+			memcpy(vbase + (px + x) * pixsize,
+			       vbuf + (px + out_x) * pixsize,
+			       pixsize);
+		}
+		vbase += dev->fb_cap.fmt.bytesperline;
+	}
+}
+
+static void vivid_thread_vid_cap_tick(struct vivid_dev *dev, int dropped_bufs)
+{
+	struct vivid_buffer *vid_cap_buf = NULL;
+	struct vivid_buffer *vbi_cap_buf = NULL;
+
+	dprintk(dev, 1, "Video Capture Thread Tick\n");
+
+	while (dropped_bufs-- > 1)
+		tpg_update_mv_count(&dev->tpg,
+				dev->field_cap == V4L2_FIELD_NONE ||
+				dev->field_cap == V4L2_FIELD_ALTERNATE);
+
+	/* Drop a certain percentage of buffers. */
+	if (dev->perc_dropped_buffers &&
+	    prandom_u32_max(100) < dev->perc_dropped_buffers)
+		goto update_mv;
+
+	spin_lock(&dev->slock);
+	if (!list_empty(&dev->vid_cap_active)) {
+		vid_cap_buf = list_entry(dev->vid_cap_active.next, struct vivid_buffer, list);
+		list_del(&vid_cap_buf->list);
+	}
+	if (!list_empty(&dev->vbi_cap_active)) {
+		if (dev->field_cap != V4L2_FIELD_ALTERNATE ||
+		    (dev->vbi_cap_seq_count & 1)) {
+			vbi_cap_buf = list_entry(dev->vbi_cap_active.next,
+						 struct vivid_buffer, list);
+			list_del(&vbi_cap_buf->list);
+		}
+	}
+	spin_unlock(&dev->slock);
+
+	if (!vid_cap_buf && !vbi_cap_buf)
+		goto update_mv;
+
+	if (vid_cap_buf) {
+		/* Fill buffer */
+		vivid_fillbuff(dev, vid_cap_buf);
+		dprintk(dev, 1, "filled buffer %d\n",
+			vid_cap_buf->vb.v4l2_buf.index);
+
+		/* Handle overlay */
+		if (dev->overlay_cap_owner && dev->fb_cap.base &&
+				dev->fb_cap.fmt.pixelformat == dev->fmt_cap->fourcc)
+			vivid_overlay(dev, vid_cap_buf);
+
+		vb2_buffer_done(&vid_cap_buf->vb, dev->dqbuf_error ?
+				VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
+		dprintk(dev, 2, "vid_cap buffer %d done\n",
+				vid_cap_buf->vb.v4l2_buf.index);
+	}
+
+	if (vbi_cap_buf) {
+		if (dev->stream_sliced_vbi_cap)
+			vivid_sliced_vbi_cap_process(dev, vbi_cap_buf);
+		else
+			vivid_raw_vbi_cap_process(dev, vbi_cap_buf);
+		vb2_buffer_done(&vbi_cap_buf->vb, dev->dqbuf_error ?
+				VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
+		dprintk(dev, 2, "vbi_cap %d done\n",
+				vbi_cap_buf->vb.v4l2_buf.index);
+	}
+	dev->dqbuf_error = false;
+
+update_mv:
+	/* Update the test pattern movement counters */
+	tpg_update_mv_count(&dev->tpg, dev->field_cap == V4L2_FIELD_NONE ||
+				       dev->field_cap == V4L2_FIELD_ALTERNATE);
+}
+
+static int vivid_thread_vid_cap(void *data)
+{
+	struct vivid_dev *dev = data;
+	u64 numerators_since_start;
+	u64 buffers_since_start;
+	u64 next_jiffies_since_start;
+	unsigned long jiffies_since_start;
+	unsigned long cur_jiffies;
+	unsigned wait_jiffies;
+	unsigned numerator;
+	unsigned denominator;
+	int dropped_bufs;
+
+	dprintk(dev, 1, "Video Capture Thread Start\n");
+
+	set_freezable();
+
+	/* Resets frame counters */
+	dev->cap_seq_offset = 0;
+	dev->cap_seq_count = 0;
+	dev->cap_seq_resync = false;
+	dev->jiffies_vid_cap = jiffies;
+
+	for (;;) {
+		try_to_freeze();
+		if (kthread_should_stop())
+			break;
+
+		mutex_lock(&dev->mutex);
+		cur_jiffies = jiffies;
+		if (dev->cap_seq_resync) {
+			dev->jiffies_vid_cap = cur_jiffies;
+			dev->cap_seq_offset = dev->cap_seq_count + 1;
+			dev->cap_seq_count = 0;
+			dev->cap_seq_resync = false;
+		}
+		numerator = dev->timeperframe_vid_cap.numerator;
+		denominator = dev->timeperframe_vid_cap.denominator;
+
+		if (dev->field_cap == V4L2_FIELD_ALTERNATE)
+			denominator *= 2;
+
+		/* Calculate the number of jiffies since we started streaming */
+		jiffies_since_start = cur_jiffies - dev->jiffies_vid_cap;
+		/* Get the number of buffers streamed since the start */
+		buffers_since_start = (u64)jiffies_since_start * denominator +
+				      (HZ * numerator) / 2;
+		do_div(buffers_since_start, HZ * numerator);
+
+		/*
+		 * After more than 0xf0000000 (rounded down to a multiple of
+		 * 'jiffies-per-day' to ease jiffies_to_msecs calculation)
+		 * jiffies have passed since we started streaming reset the
+		 * counters and keep track of the sequence offset.
+		 */
+		if (jiffies_since_start > JIFFIES_RESYNC) {
+			dev->jiffies_vid_cap = cur_jiffies;
+			dev->cap_seq_offset = buffers_since_start;
+			buffers_since_start = 0;
+		}
+		dropped_bufs = buffers_since_start + dev->cap_seq_offset - dev->cap_seq_count;
+		dev->cap_seq_count = buffers_since_start + dev->cap_seq_offset;
+		dev->vid_cap_seq_count = dev->cap_seq_count - dev->vid_cap_seq_start;
+		dev->vbi_cap_seq_count = dev->cap_seq_count - dev->vbi_cap_seq_start;
+
+		vivid_thread_vid_cap_tick(dev, dropped_bufs);
+
+		/*
+		 * Calculate the number of 'numerators' streamed since we started,
+		 * including the current buffer.
+		 */
+		numerators_since_start = ++buffers_since_start * numerator;
+
+		/* And the number of jiffies since we started */
+		jiffies_since_start = jiffies - dev->jiffies_vid_cap;
+
+		mutex_unlock(&dev->mutex);
+
+		/*
+		 * Calculate when that next buffer is supposed to start
+		 * in jiffies since we started streaming.
+		 */
+		next_jiffies_since_start = numerators_since_start * HZ +
+					   denominator / 2;
+		do_div(next_jiffies_since_start, denominator);
+		/* If it is in the past, then just schedule asap */
+		if (next_jiffies_since_start < jiffies_since_start)
+			next_jiffies_since_start = jiffies_since_start;
+
+		wait_jiffies = next_jiffies_since_start - jiffies_since_start;
+		schedule_timeout_interruptible(wait_jiffies ? wait_jiffies : 1);
+	}
+	dprintk(dev, 1, "Video Capture Thread End\n");
+	return 0;
+}
+
+static void vivid_grab_controls(struct vivid_dev *dev, bool grab)
+{
+	v4l2_ctrl_grab(dev->ctrl_has_crop_cap, grab);
+	v4l2_ctrl_grab(dev->ctrl_has_compose_cap, grab);
+	v4l2_ctrl_grab(dev->ctrl_has_scaler_cap, grab);
+}
+
+int vivid_start_generating_vid_cap(struct vivid_dev *dev, bool *pstreaming)
+{
+	dprintk(dev, 1, "%s\n", __func__);
+
+	if (dev->kthread_vid_cap) {
+		u32 seq_count = dev->cap_seq_count + dev->seq_wrap * 128;
+
+		if (pstreaming == &dev->vid_cap_streaming)
+			dev->vid_cap_seq_start = seq_count;
+		else
+			dev->vbi_cap_seq_start = seq_count;
+		*pstreaming = true;
+		return 0;
+	}
+
+	/* Resets frame counters */
+	tpg_init_mv_count(&dev->tpg);
+
+	dev->vid_cap_seq_start = dev->seq_wrap * 128;
+	dev->vbi_cap_seq_start = dev->seq_wrap * 128;
+
+	dev->kthread_vid_cap = kthread_run(vivid_thread_vid_cap, dev,
+			"%s-vid-cap", dev->v4l2_dev.name);
+
+	if (IS_ERR(dev->kthread_vid_cap)) {
+		v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n");
+		return PTR_ERR(dev->kthread_vid_cap);
+	}
+	*pstreaming = true;
+	vivid_grab_controls(dev, true);
+
+	dprintk(dev, 1, "returning from %s\n", __func__);
+	return 0;
+}
+
+void vivid_stop_generating_vid_cap(struct vivid_dev *dev, bool *pstreaming)
+{
+	dprintk(dev, 1, "%s\n", __func__);
+
+	if (dev->kthread_vid_cap == NULL)
+		return;
+
+	*pstreaming = false;
+	if (pstreaming == &dev->vid_cap_streaming) {
+		/* Release all active buffers */
+		while (!list_empty(&dev->vid_cap_active)) {
+			struct vivid_buffer *buf;
+
+			buf = list_entry(dev->vid_cap_active.next,
+					 struct vivid_buffer, list);
+			list_del(&buf->list);
+			vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
+			dprintk(dev, 2, "vid_cap buffer %d done\n",
+				buf->vb.v4l2_buf.index);
+		}
+	}
+
+	if (pstreaming == &dev->vbi_cap_streaming) {
+		while (!list_empty(&dev->vbi_cap_active)) {
+			struct vivid_buffer *buf;
+
+			buf = list_entry(dev->vbi_cap_active.next,
+					 struct vivid_buffer, list);
+			list_del(&buf->list);
+			vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
+			dprintk(dev, 2, "vbi_cap buffer %d done\n",
+				buf->vb.v4l2_buf.index);
+		}
+	}
+
+	if (dev->vid_cap_streaming || dev->vbi_cap_streaming)
+		return;
+
+	/* shutdown control thread */
+	vivid_grab_controls(dev, false);
+	mutex_unlock(&dev->mutex);
+	kthread_stop(dev->kthread_vid_cap);
+	dev->kthread_vid_cap = NULL;
+	mutex_lock(&dev->mutex);
+}

drivers/media/platform/vivid/vivid-kthread-cap.h

+/*
+ * vivid-kthread-cap.h - video/vbi capture thread support functions.
+ *
+ * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef _VIVID_KTHREAD_CAP_H_
+#define _VIVID_KTHREAD_CAP_H_
+
+int vivid_start_generating_vid_cap(struct vivid_dev *dev, bool *pstreaming);
+void vivid_stop_generating_vid_cap(struct vivid_dev *dev, bool *pstreaming);
+
+#endif

drivers/media/platform/vivid/vivid-kthread-out.c

+/*
+ * vivid-kthread-out.h - video/vbi output thread support functions.
+ *
+ * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/font.h>
+#include <linux/mutex.h>
+#include <linux/videodev2.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/random.h>
+#include <linux/v4l2-dv-timings.h>
+#include <asm/div64.h>
+#include <media/videobuf2-vmalloc.h>
+#include <media/v4l2-dv-timings.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-fh.h>
+#include <media/v4l2-event.h>
+
+#include "vivid-core.h"
+#include "vivid-vid-common.h"
+#include "vivid-vid-cap.h"
+#include "vivid-vid-out.h"
+#include "vivid-radio-common.h"
+#include "vivid-radio-rx.h"
+#include "vivid-radio-tx.h"
+#include "vivid-sdr-cap.h"
+#include "vivid-vbi-cap.h"
+#include "vivid-vbi-out.h"
+#include "vivid-osd.h"
+#include "vivid-ctrls.h"
+
+static void vivid_thread_vid_out_tick(struct vivid_dev *dev)
+{
+	struct vivid_buffer *vid_out_buf = NULL;
+	struct vivid_buffer *vbi_out_buf = NULL;
+
+	dprintk(dev, 1, "Video Output Thread Tick\n");
+
+	/* Drop a certain percentage of buffers. */
+	if (dev->perc_dropped_buffers &&
+	    prandom_u32_max(100) < dev->perc_dropped_buffers)
+		return;
+
+	spin_lock(&dev->slock);
+	/*
+	 * Only dequeue buffer if there is at least one more pending.
+	 * This makes video loopback possible.
+	 */
+	if (!list_empty(&dev->vid_out_active) &&
+	    !list_is_singular(&dev->vid_out_active)) {
+		vid_out_buf = list_entry(dev->vid_out_active.next,
+					 struct vivid_buffer, list);
+		list_del(&vid_out_buf->list);
+	}
+	if (!list_empty(&dev->vbi_out_active) &&
+	    (dev->field_out != V4L2_FIELD_ALTERNATE ||
+	     (dev->vbi_out_seq_count & 1))) {
+		vbi_out_buf = list_entry(dev->vbi_out_active.next,
+					 struct vivid_buffer, list);
+		list_del(&vbi_out_buf->list);
+	}
+	spin_unlock(&dev->slock);
+
+	if (!vid_out_buf && !vbi_out_buf)
+		return;
+
+	if (vid_out_buf) {
+		vid_out_buf->vb.v4l2_buf.sequence = dev->vid_out_seq_count;
+		if (dev->field_out == V4L2_FIELD_ALTERNATE) {
+			/*
+			 * The sequence counter counts frames, not fields. So divide
+			 * by two.
+			 */
+			vid_out_buf->vb.v4l2_buf.sequence /= 2;
+		}
+		v4l2_get_timestamp(&vid_out_buf->vb.v4l2_buf.timestamp);
+		vid_out_buf->vb.v4l2_buf.timestamp.tv_sec += dev->time_wrap_offset;
+		vb2_buffer_done(&vid_out_buf->vb, dev->dqbuf_error ?
+				VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
+		dprintk(dev, 2, "vid_out buffer %d done\n",
+			vid_out_buf->vb.v4l2_buf.index);
+	}
+
+	if (vbi_out_buf) {
+		if (dev->stream_sliced_vbi_out)
+			vivid_sliced_vbi_out_process(dev, vbi_out_buf);
+
+		vbi_out_buf->vb.v4l2_buf.sequence = dev->vbi_out_seq_count;
+		v4l2_get_timestamp(&vbi_out_buf->vb.v4l2_buf.timestamp);
+		vbi_out_buf->vb.v4l2_buf.timestamp.tv_sec += dev->time_wrap_offset;
+		vb2_buffer_done(&vbi_out_buf->vb, dev->dqbuf_error ?
+				VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
+		dprintk(dev, 2, "vbi_out buffer %d done\n",
+			vbi_out_buf->vb.v4l2_buf.index);
+	}
+	dev->dqbuf_error = false;
+}
+
+static int vivid_thread_vid_out(void *data)
+{
+	struct vivid_dev *dev = data;
+	u64 numerators_since_start;
+	u64 buffers_since_start;
+	u64 next_jiffies_since_start;
+	unsigned long jiffies_since_start;
+	unsigned long cur_jiffies;
+	unsigned wait_jiffies;
+	unsigned numerator;
+	unsigned denominator;
+
+	dprintk(dev, 1, "Video Output Thread Start\n");
+
+	set_freezable();
+
+	/* Resets frame counters */
+	dev->out_seq_offset = 0;
+	if (dev->seq_wrap)
+		dev->out_seq_count = 0xffffff80U;
+	dev->jiffies_vid_out = jiffies;
+	dev->vid_out_seq_start = dev->vbi_out_seq_start = 0;
+	dev->out_seq_resync = false;
+
+	for (;;) {
+		try_to_freeze();
+		if (kthread_should_stop())
+			break;
+
+		mutex_lock(&dev->mutex);
+		cur_jiffies = jiffies;
+		if (dev->out_seq_resync) {
+			dev->jiffies_vid_out = cur_jiffies;
+			dev->out_seq_offset = dev->out_seq_count + 1;
+			dev->out_seq_count = 0;
+			dev->out_seq_resync = false;
+		}
+		numerator = dev->timeperframe_vid_out.numerator;
+		denominator = dev->timeperframe_vid_out.denominator;
+
+		if (dev->field_out == V4L2_FIELD_ALTERNATE)
+			denominator *= 2;
+
+		/* Calculate the number of jiffies since we started streaming */
+		jiffies_since_start = cur_jiffies - dev->jiffies_vid_out;
+		/* Get the number of buffers streamed since the start */
+		buffers_since_start = (u64)jiffies_since_start * denominator +
+				      (HZ * numerator) / 2;
+		do_div(buffers_since_start, HZ * numerator);
+
+		/*
+		 * After more than 0xf0000000 (rounded down to a multiple of
+		 * 'jiffies-per-day' to ease jiffies_to_msecs calculation)
+		 * jiffies have passed since we started streaming reset the
+		 * counters and keep track of the sequence offset.
+		 */
+		if (jiffies_since_start > JIFFIES_RESYNC) {
+			dev->jiffies_vid_out = cur_jiffies;
+			dev->out_seq_offset = buffers_since_start;
+			buffers_since_start = 0;
+		}
+		dev->out_seq_count = buffers_since_start + dev->out_seq_offset;
+		dev->vid_out_seq_count = dev->out_seq_count - dev->vid_out_seq_start;
+		dev->vbi_out_seq_count = dev->out_seq_count - dev->vbi_out_seq_start;
+
+		vivid_thread_vid_out_tick(dev);
+		mutex_unlock(&dev->mutex);
+
+		/*
+		 * Calculate the number of 'numerators' streamed since we started,
+		 * not including the current buffer.
+		 */
+		numerators_since_start = buffers_since_start * numerator;
+
+		/* And the number of jiffies since we started */
+		jiffies_since_start = jiffies - dev->jiffies_vid_out;
+
+		/* Increase by the 'numerator' of one buffer */
+		numerators_since_start += numerator;
+		/*
+		 * Calculate when that next buffer is supposed to start
+		 * in jiffies since we started streaming.
+		 */
+		next_jiffies_since_start = numerators_since_start * HZ +
+					   denominator / 2;
+		do_div(next_jiffies_since_start, denominator);
+		/* If it is in the past, then just schedule asap */
+		if (next_jiffies_since_start < jiffies_since_start)
+			next_jiffies_since_start = jiffies_since_start;
+
+		wait_jiffies = next_jiffies_since_start - jiffies_since_start;
+		schedule_timeout_interruptible(wait_jiffies ? wait_jiffies : 1);
+	}
+	dprintk(dev, 1, "Video Output Thread End\n");
+	return 0;
+}
+
+static void vivid_grab_controls(struct vivid_dev *dev, bool grab)
+{
+	v4l2_ctrl_grab(dev->ctrl_has_crop_out, grab);
+	v4l2_ctrl_grab(dev->ctrl_has_compose_out, grab);
+	v4l2_ctrl_grab(dev->ctrl_has_scaler_out, grab);
+	v4l2_ctrl_grab(dev->ctrl_tx_mode, grab);
+	v4l2_ctrl_grab(dev->ctrl_tx_rgb_range, grab);
+}
+
+int vivid_start_generating_vid_out(struct vivid_dev *dev, bool *pstreaming)
+{
+	dprintk(dev, 1, "%s\n", __func__);
+
+	if (dev->kthread_vid_out) {
+		u32 seq_count = dev->out_seq_count + dev->seq_wrap * 128;
+
+		if (pstreaming == &dev->vid_out_streaming)
+			dev->vid_out_seq_start = seq_count;
+		else
+			dev->vbi_out_seq_start = seq_count;
+		*pstreaming = true;
+		return 0;
+	}
+
+	/* Resets frame counters */
+	dev->jiffies_vid_out = jiffies;
+	dev->vid_out_seq_start = dev->seq_wrap * 128;
+	dev->vbi_out_seq_start = dev->seq_wrap * 128;
+
+	dev->kthread_vid_out = kthread_run(vivid_thread_vid_out, dev,
+			"%s-vid-out", dev->v4l2_dev.name);
+
+	if (IS_ERR(dev->kthread_vid_out)) {
+		v4l2_err(&dev->v4l2_dev, "kernel_thread() failed\n");
+		return PTR_ERR(dev->kthread_vid_out);
+	}
+	*pstreaming = true;
+	vivid_grab_controls(dev, true);
+
+	dprintk(dev, 1, "returning from %s\n", __func__);
+	return 0;
+}
+
+void vivid_stop_generating_vid_out(struct vivid_dev *dev, bool *pstreaming)
+{
+	dprintk(dev, 1, "%s\n", __func__);
+
+	if (dev->kthread_vid_out == NULL)
+		return;
+
+	*pstreaming = false;
+	if (pstreaming == &dev->vid_out_streaming) {
+		/* Release all active buffers */
+		while (!list_empty(&dev->vid_out_active)) {
+			struct vivid_buffer *buf;
+
+			buf = list_entry(dev->vid_out_active.next,
+					 struct vivid_buffer, list);
+			list_del(&buf->list);
+			vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
+			dprintk(dev, 2, "vid_out buffer %d done\n",
+				buf->vb.v4l2_buf.index);
+		}
+	}
+
+	if (pstreaming == &dev->vbi_out_streaming) {
+		while (!list_empty(&dev->vbi_out_active)) {
+			struct vivid_buffer *buf;
+
+			buf = list_entry(dev->vbi_out_active.next,
+					 struct vivid_buffer, list);
+			list_del(&buf->list);
+			vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
+			dprintk(dev, 2, "vbi_out buffer %d done\n",
+				buf->vb.v4l2_buf.index);
+		}
+	}
+
+	if (dev->vid_out_streaming || dev->vbi_out_streaming)
+		return;
+
+	/* shutdown control thread */
+	vivid_grab_controls(dev, false);
+	mutex_unlock(&dev->mutex);
+	kthread_stop(dev->kthread_vid_out);
+	dev->kthread_vid_out = NULL;
+	mutex_lock(&dev->mutex);
+}

drivers/media/platform/vivid/vivid-kthread-out.h

+/*
+ * vivid-kthread-out.h - video/vbi output thread support functions.
+ *
+ * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef _VIVID_KTHREAD_OUT_H_
+#define _VIVID_KTHREAD_OUT_H_
+
+int vivid_start_generating_vid_out(struct vivid_dev *dev, bool *pstreaming);
+void vivid_stop_generating_vid_out(struct vivid_dev *dev, bool *pstreaming);
+
+#endif