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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>
This commit is contained in:
Ian Armstrong 2010-03-13 20:22:34 -03:00 committed by Mauro Carvalho Chehab
parent f978ac90b2
commit 2443baeaa0
2 changed files with 25 additions and 1 deletions
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5
drivers/media/video/ivtv/ivtv-driver.c
View File

@ -1293,7 +1293,6 @@ int ivtv_init_on_first_open(struct ivtv *itv)
ivtv_call_hw(itv, IVTV_HW_SAA7127, video, s_stream, 1);
ivtv_init_mpeg_decoder(itv);
}
ivtv_s_std(NULL, &fh, &itv->tuner_std);
/* On a cx23416 this seems to be able to enable DMA to the chip? */
if (!itv->has_cx23415)
@ -1310,6 +1309,10 @@ int ivtv_init_on_first_open(struct ivtv *itv)
}
else
ivtv_clear_irq_mask(itv, IVTV_IRQ_MASK_INIT);
/* For cards with video out, this call needs interrupts enabled */
ivtv_s_std(NULL, &fh, &itv->tuner_std);
return 0;
}

21
drivers/media/video/ivtv/ivtv-ioctl.c
View File

@ -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;