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From: Pantelis Koukousoulas <pakt223@freemail.gr>
This is the logic that supports switching modes via e.g.,
echo radio > /sys/class/pvrusb2/sn-*/ctl_input/cur_val.
To do the mode switching we need to a) broadcast AUDC_SET_RADIO and
b) issue the CX2341X_ENC_MUTE_VIDEO command to the encoder. The first is
done by adding a new pvr2_i2c_op and having it trigger on input change,
the second by adding this command in pvr2_encoder_start() and requesting
an encoder restart on input change by setting stale_subsys_mask appropriately.
The clues about AUDC_SET_RADIO and CX2341X_ENC_MUTE_VIDEO were kindly provided
by Hans Verkuil on the pvrusb2 mailing list. The idea to implement mode
switching this way (on input change) is due to Mike Isely.
Why AUDC_SET_RADIO/VIDIOC_S_STD are used for switching? I can 't be sure, but
I think this can be traced to a cornell student being the first to implement
radio support in ivtv "as a different standard". I think the rest just evolved
from there (it 's in the ivtv ML archives).
--Pantelis
Signed-off-by: Pantelis Koukousoulas <pakt223@freemail.gr>
Signed-off-by: Mike Isely <isely@pobox.com>
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