DVB Access Module disallows valid modulations for ATSC tuners
[18949] (as a fix to #1063 (closed)) changes the mechanism for assigning a modulation to assign modulations that are appropriate for the type of frontend being used. However, the type of frontend does not actually predict the modulations it supports. In particular, many ATSC frontends support both 8VSB and QAM, such as the K-World ATSC-110 that I have:
[00000376] dvb access debug: Opening device /dev/dvb/adapter0/frontend0
[00000376] dvb access debug: Frontend Info:
[00000376] dvb access debug: name = Nextwave NXT200X VSB/QAM frontend
[00000376] dvb access debug: type = ATSC (USA)
[00000376] dvb access debug: frequency_min = 54000000 (kHz)
[00000376] dvb access debug: frequency_max = 860000000 (kHz)
[00000376] dvb access debug: frequency_stepsize = 166666
[00000376] dvb access debug: frequency_tolerance = 0
[00000376] dvb access debug: symbol_rate_min = 0 (kHz)
[00000376] dvb access debug: symbol_rate_max = 0 (kHz)
[00000376] dvb access debug: symbol_rate_tolerance (ppm) = 0
[00000376] dvb access debug: notifier_delay (ms) = 0
[00000376] dvb access debug: Frontend Info capability list:
[00000376] dvb access debug: inversion auto
[00000376] dvb access debug: forward error correction 1/2
[00000376] dvb access debug: forward error correction 2/3
[00000376] dvb access debug: forward error correction 3/4
[00000376] dvb access debug: forward error correction 5/6
[00000376] dvb access debug: forward error correction 7/8
[00000376] dvb access debug: forward error correction auto
[00000376] dvb access debug: card can do QAM 64
[00000376] dvb access debug: card can do QAM 256
[00000376] dvb access debug: card can do 8vsb
[00000376] dvb access debug: End of capability list
Post-r18949, I can no longer tune QAM channels because VLC fails to set the modulation, logging "ATSC modulation not set, using VSB 8".
I think that r18949 should be reverted, as the fix causes more problems than the original problem (lack of a sane default for ATSC tuners)