Re: HVR-930C DVB-T mode report

[Mauro Carvalho Chehab <mchehab@redhat.com>]

On 08-12-2011 13:06, Mauro Carvalho Chehab wrote:
> On 08-12-2011 12:00, Fredrik Lingvall wrote:
>> On 12/08/11 11:12, Mauro Carvalho Chehab wrote:
>>>> -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
>>>> Scanning 7MHz frequencies...
>>>> 177500: (time: 00:00)
>>>> 184500: (time: 00:03)
>>>>
>>>> [...]
>>>> 834000: (time: 02:46) (time: 02:48)
>>>> 842000: (time: 02:50)
>>>> 850000: (time: 02:52) (time: 02:55)
>>>> 858000: (time: 02:56) (time: 02:58)
>>>>
>>>> ERROR: Sorry - i couldn't get any working frequency/transponder
>>>> Nothing to scan!!
>>>
>>>
>>> With regards to Italy, w_scan does something different than scan. The auto-italy
>>> table used by scan tries several channels with both 8MHz and 7MHz, while w_scan
>>> only tries 7MHz for VHF. This might explain the issue, if you're still able to
>>> scan/tune with scan and if you have a good antenna.
>>>>
>>>>
>>>> Regards
>>>>
>>>> Eddi
>>>
>>> --
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>>
>> Are there similar problems while scanning DVB-C nets with w_scan?
>>
>> And, is there a "scan everything" table for dvbscan?
>
> No. Both w_scan/dvbscan get the same channels, and they match the channels
> available at the STB and with other boards.
>
> Btw, drivers/media/common/tuners/xc5000.c doesn't support 7MHz for DVB-T:
>
> case BANDWIDTH_7_MHZ:
> printk(KERN_ERR "xc5000 bandwidth 7MHz not supported\n");
> return -EINVAL;
>
> This may explain why you're getting so few channels on it. Only channels marked as
> 8MHz will be tuned.
>
> I _suspect_ that:
> case BANDWIDTH_7_MHZ:
> case BANDWIDTH_8_MHZ:
> priv->bandwidth = BANDWIDTH_8_MHZ;
> priv->video_standard = DTV8;
> priv->freq_hz = params->frequency - 2750000;
> break;

On a more detailed look, I suspect that the reason why DTV7 was not implemented is
because there are two ways of supporting it: via DTV_78 or via DTV-8.

While I'm not sure about the frequency offset for DTV7, I suspect it is 2250000. Could
you please try the enclosed patch and see if it improves DVB-T and DVB-C detection?

Devin/Steven/Michael,

Could you please double check what is the offset for the center frequency to
be used on a 7MHz firmware on xc5000? I suspect it should be 2.25 MHz.

People are reporting troubles with HVR-930C channel detection, and I suspect that the
issue is due to the lack of proper support for 7MHz.

Regards,
Mauro

-

[media] xc5000: Add support for 7MHz-spaced channels

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/common/tuners/xc5000.c b/drivers/media/common/tuners/xc5000.c
index 19990bc..97ad338 100644
--- a/drivers/media/common/tuners/xc5000.c
+++ b/drivers/media/common/tuners/xc5000.c
@@ -676,8 +676,10 @@ static int xc5000_set_params(struct dvb_frontend *fe,
  			priv->freq_hz = params->frequency - 1750000;
  			break;
  		case BANDWIDTH_7_MHZ:
-			printk(KERN_ERR "xc5000 bandwidth 7MHz not supported\n");
-			return -EINVAL;
+			priv->bandwidth = BANDWIDTH_7_MHZ;
+			priv->video_standard = DTV7;
+			priv->freq_hz = params->frequency - 2250000;
+			break;
  		case BANDWIDTH_8_MHZ:
  			priv->bandwidth = BANDWIDTH_8_MHZ;
  			priv->video_standard = DTV8;
@@ -715,6 +717,10 @@ static int xc5000_set_params(struct dvb_frontend *fe,
  				priv->bandwidth = BANDWIDTH_6_MHZ;
  				priv->video_standard = DTV6;
  				priv->freq_hz = params->frequency - 1750000;
+			} else if (bw <= 7000000) {
+				priv->bandwidth = BANDWIDTH_7_MHZ;
+				priv->video_standard = DTV7;
+				priv->freq_hz = params->frequency - 2250000;
  			} else {
  				priv->bandwidth = BANDWIDTH_8_MHZ;
  				priv->video_standard = DTV7_8;