V4L/DVB (9166): ivtv - Fix potential race condition in yuv handler
Modified yuv register update handling to remove a potential race condition
which could occur with the first video frame.
Also removed a forced yuv position update, since changing the source video
dimensions or interlace settings doesn't affect the frame already being
displayed.
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@redhat.com>
diff --git a/drivers/media/video/ivtv/ivtv-driver.h b/drivers/media/video/ivtv/ivtv-driver.h
index be2d779..bc29436 100644
--- a/drivers/media/video/ivtv/ivtv-driver.h
+++ b/drivers/media/video/ivtv/ivtv-driver.h
@@ -506,6 +506,8 @@
struct v4l2_rect main_rect;
u32 v4l2_src_w;
u32 v4l2_src_h;
+
+ u8 running; /* Have any frames been displayed */
};
#define IVTV_VBI_FRAMES 32
diff --git a/drivers/media/video/ivtv/ivtv-ioctl.c b/drivers/media/video/ivtv/ivtv-ioctl.c
index 3c2628a..8696527 100644
--- a/drivers/media/video/ivtv/ivtv-ioctl.c
+++ b/drivers/media/video/ivtv/ivtv-ioctl.c
@@ -644,8 +644,6 @@
itv->dma_data_req_size =
1080 * ((yi->v4l2_src_h + 31) & ~31);
- /* Force update of yuv registers */
- yi->yuv_forced_update = 1;
return 0;
}
diff --git a/drivers/media/video/ivtv/ivtv-irq.c b/drivers/media/video/ivtv/ivtv-irq.c
index 34f3ab8..f5d00ec 100644
--- a/drivers/media/video/ivtv/ivtv-irq.c
+++ b/drivers/media/video/ivtv/ivtv-irq.c
@@ -753,7 +753,7 @@
*/
unsigned int frame = read_reg(0x28c0) & 1;
struct yuv_playback_info *yi = &itv->yuv_info;
- int last_dma_frame = atomic_read(&itv->yuv_info.next_dma_frame);
+ int last_dma_frame = atomic_read(&yi->next_dma_frame);
struct yuv_frame_info *f = &yi->new_frame_info[last_dma_frame];
if (0) IVTV_DEBUG_IRQ("DEC VSYNC\n");
@@ -772,6 +772,7 @@
next_dma_frame = (next_dma_frame + 1) % IVTV_YUV_BUFFERS;
atomic_set(&yi->next_dma_frame, next_dma_frame);
yi->fields_lapsed = -1;
+ yi->running = 1;
}
}
}
@@ -804,9 +805,11 @@
}
/* Check if we need to update the yuv registers */
- if ((yi->yuv_forced_update || f->update) && last_dma_frame != -1) {
+ if (yi->running && (yi->yuv_forced_update || f->update)) {
if (!f->update) {
- last_dma_frame = (u8)(last_dma_frame - 1) % IVTV_YUV_BUFFERS;
+ last_dma_frame =
+ (u8)(atomic_read(&yi->next_dma_frame) -
+ 1) % IVTV_YUV_BUFFERS;
f = &yi->new_frame_info[last_dma_frame];
}
diff --git a/drivers/media/video/ivtv/ivtv-yuv.c b/drivers/media/video/ivtv/ivtv-yuv.c
index 3092ff1..ee91107 100644
--- a/drivers/media/video/ivtv/ivtv-yuv.c
+++ b/drivers/media/video/ivtv/ivtv-yuv.c
@@ -1147,6 +1147,7 @@
IVTV_DEBUG_YUV("ivtv_yuv_close\n");
ivtv_waitq(&itv->vsync_waitq);
+ yi->running = 0;
atomic_set(&yi->next_dma_frame, -1);
atomic_set(&yi->next_fill_frame, 0);