diff options
| author | Ian Armstrong <ian@iarmst.demon.co.uk> | 2010-03-13 20:22:34 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2010-05-18 00:47:15 -0300 |
| commit | 2443baeaa01388f56824c55c087510312b8d8197 (patch) | |
| tree | e23643dce16babebfad3087dbb103249a28dec2d /drivers/media/video/ivtv/ivtv-ioctl.c | |
| parent | f978ac90b2cfa79cb075f74fd5c403e9f9ec4246 (diff) | |
V4L/DVB: ivtv: Avoid hard system lock on decoder output mode change
Changing the decoder video standard just prior to, or during, the output of
the lower field may result in a hard system lock. To avoid this, try to ensure
the firmware call occurs only during the first 100 lines of the top field.
(Minor comment addition and a line break added Andy Walls <awalls@radix.net>.)
Signed-off-by: Ian Armstrong <ian@iarmst.demon.co.uk>
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/ivtv/ivtv-ioctl.c')
| -rw-r--r-- | drivers/media/video/ivtv/ivtv-ioctl.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/media/video/ivtv/ivtv-ioctl.c b/drivers/media/video/ivtv/ivtv-ioctl.c index 99f3c39a118b..2192bc42c6b6 100644 --- a/drivers/media/video/ivtv/ivtv-ioctl.c +++ b/drivers/media/video/ivtv/ivtv-ioctl.c @@ -1087,8 +1087,10 @@ static int ivtv_g_std(struct file *file, void *fh, v4l2_std_id *std) int ivtv_s_std(struct file *file, void *fh, v4l2_std_id *std) { + DEFINE_WAIT(wait); struct ivtv *itv = ((struct ivtv_open_id *)fh)->itv; struct yuv_playback_info *yi = &itv->yuv_info; + int f; if ((*std & V4L2_STD_ALL) == 0) return -EINVAL; @@ -1128,6 +1130,25 @@ int ivtv_s_std(struct file *file, void *fh, v4l2_std_id *std) itv->is_out_60hz = itv->is_60hz; itv->is_out_50hz = itv->is_50hz; ivtv_call_all(itv, video, s_std_output, itv->std_out); + + /* + * The next firmware call is time sensitive. Time it to + * avoid risk of a hard lock, by trying to ensure the call + * happens within the first 100 lines of the top field. + * Make 4 attempts to sync to the decoder before giving up. + */ + for (f = 0; f < 4; f++) { + prepare_to_wait(&itv->vsync_waitq, &wait, + TASK_UNINTERRUPTIBLE); + if ((read_reg(0x28c0) >> 16) < 100) + break; + schedule_timeout(msecs_to_jiffies(25)); + } + finish_wait(&itv->vsync_waitq, &wait); + + if (f == 4) + IVTV_WARN("Mode change failed to sync to decoder\n"); + ivtv_vapi(itv, CX2341X_DEC_SET_STANDARD, 1, itv->is_out_50hz); itv->main_rect.left = itv->main_rect.top = 0; itv->main_rect.width = 720; |