V4L/DVB: ivtv: Adjust msleep() delays used to prevent tinny audio and PCI bus hang

Martin Dauskardt <martin.dauskardt@gmx.de> has done extensive testing on what
values can be used and and concluded that only 300 ms total is required to
avoid bad video effects such as occasional black screen and short sync
disturbances.  Furthermore he determined how this 300 ms was split between
the two msleep()s did matter very much, so he suggested 150ms/150ms as one
acceptable alternative that is implemented here.

Many thanks go to Martin.

Tested-by: Martin Dauskardt <martin.dauskardt@gmx.de>
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/ivtv/ivtv-streams.c b/drivers/media/video/ivtv/ivtv-streams.c
index 2f90dd2..1f9387f 100644 (file)
--- a/drivers/media/video/ivtv/ivtv-streams.c
+++ b/drivers/media/video/ivtv/ivtv-streams.c
@@ -581,10 +581,10 @@ int ivtv_start_v4l2_encode_stream(struct ivtv_stream *s)
                v4l2_subdev_call(itv->sd_audio, audio, s_stream, 1);
                /* Avoid unpredictable PCI bus hang - disable video clocks */
                v4l2_subdev_call(itv->sd_video, video, s_stream, 0);
-               ivtv_msleep_timeout(300, 1);
+               ivtv_msleep_timeout(150, 1);
                ivtv_vapi(itv, CX2341X_ENC_INITIALIZE_INPUT, 0);
                v4l2_subdev_call(itv->sd_video, video, s_stream, 1);
-               ivtv_msleep_timeout(300, 1);
+               ivtv_msleep_timeout(150, 1);
        }
 
        /* begin_capture */