On Sun, 2009-05-31 at 10:22 -0300, Mauro Carvalho Chehab wrote: > Em Sun, 31 May 2009 08:41:43 -0400 > Andy Walls <awalls@xxxxxxxxx> escreveu: > > > This is a patch with changes provided by Terry Wu to support 6 MHz DVB-T > > as is deployed in Taiwan. > > > > > > I took quick look at the changes and they look OK to me, but I'm no > > expert on the XC2028/XC3028 deivces. > > > > My one observation is that the change assumes all COFDM frontends can > > support QAM (FE_CAN_QAM..). This is apparently the case looking through > > all the Linux supported FE_OFDM frontends, and it seems like a > > reasonable assumption to me. > > > > > > Terry, > > > > Please check the diff below, to make sure I captured all your changes. > > > > For inclusion into the kernel, you will need to provide a > > "Signed-off-by:" in a rely to this patch list posting. Please see: > > > > http://www.linuxtv.org/wiki/index.php/Development:_Submitting_Patches#Developer.27s_Certificate_of_Origin_1.1 > > > > > > Regards, > > Andy > > > > > > diff -r 8291f6042c9a linux/drivers/media/common/tuners/tuner-xc2028.c > > --- a/linux/drivers/media/common/tuners/tuner-xc2028.c Fri May 29 21:19:25 2009 -0400 > > +++ b/linux/drivers/media/common/tuners/tuner-xc2028.c Sun May 31 08:29:32 2009 -0400 > > @@ -925,6 +925,9 @@ > > rc = send_seq(priv, {0x00, 0x00}); > > } else if (priv->cur_fw.type & ATSC) { > > offset = 1750000; > > + } else if (priv->cur_fw.type & DTV6) { > > + /* For Taiwan DVB-T 6 MHz bandwidth - Terry Wu */ > > + offset = 1750000; > > This is wrong, since it will break xc3028 for all other DVB-T standards. > The offset depends on the demod type. He probably choose the wrong IF for the demod. > > Terry, please provide your boards entry for us to help you to properly set it. > > } else { > > offset = 2750000; > > /* > > @@ -1026,6 +1029,11 @@ > > switch(fe->ops.info.type) { > > case FE_OFDM: > > bw = p->u.ofdm.bandwidth; > > + /* For Taiwan DVB-T 6 MHz bandwidth - Terry Wu */ > > + if (bw == BANDWIDTH_6_MHZ) { > > + type |= (DTV6|QAM|D2633); > > + priv->ctrl.type = XC2028_D2633; > > + } > > Hmm... why are you asking for the QAM firmware here? Shouldn't it be at FE_QAM? I think I can provide a little insight: They way I understood things is that DVB-T demodulators (like the ZarLink used for the DTV1800 - zl10353 driver) are always of type FE_OFDM. The OFDM subcarriers for DVB-T can be modulated with QPSK or QAM (I think there is a hierarchical modulation scheme - I have to do more reading). In the Linux dvb frontend drivers, the FE_QAM type is used for only for cable TV (DVB-C) frontends. My questions: Is OFDM used for other Digital TV aside from DVB-T? Does the XC20208 have firmware explcitily for OFDM irrespective of the subcarrier modulation? Here is a list of DVB deployment reports: http://www.dvb.org/dvb-deployment-data.xls Columns Q, R and U show these countries as DVB-T in a 6 MHz bandwidth Taiwan: ~8000 subcarriers, 16 QAM Uruguay: ~2000 subcarriers, 16 QAM and 64 QAM So both of the currently deployed DVB-T systems using 6 MHz use QAM subcarriers. The only deployments using QPSK are using it in an 8 MHz bandwidth for mobile services. All the DVB demods in the v4l-dvb source tree that are FE_OFDM are marked FE_CAN_QAM_{16,64,AUTO}, except in v4l-dvb/linux/drivers/media/dvb/frontends/cx22700.c the CX22700 is not marked FE_CAN_QAM_AUTO. Regards, Andy > This will also break for other countries with 6 MHz bw. Also, priv->ctrl should > be set inside your board definitions. > > Could you please provide us more info about the DVB-T standard in Taiwan? > > > break; > > case FE_QAM: > > tuner_info("WARN: There are some reports that " > > > > > > > > > Cheers, > Mauro > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
