Log in Register FAQ Memberlist Search pcHDTV Forum Index
pcHDTV Forum

pcHDTV Forum Index -> Installation/Setup -> Lost the ability to scan digital signals after upgrade
Post new topic  Reply to topic View previous topic :: View next topic 
Lost the ability to scan digital signals after upgrade
PostPosted: Sun Apr 08, 2007 9:31 pm Reply with quote
Joined: 08 Apr 2007
Posts: 5

I am running FC6 on an Athlon 64 3500+ with two pcHDVT 5500 cards. I'm receiving both NTSC analog and QAM256 ATSC digital signals off a Comcast cable connection.

Everything was working relatively well until last week when I upgraded to the newest kernel: 2.6.20-1.2933.fc6. Now I'm not able to scan channels on the digital side of the cards. (The analog scanning and viewing works fine.) Whenever I try to run a channel scan within mythtv-setup using "Cable-high" frequencies and "Cable (QAM-256)" ATSC modulation, I get timeout signals. (This had always worked previously.) If I look at my dmesg output afterwards I see the following message, repeated many times:

lgdt330x: lgdt3303_read_status: Modulation set to unsupported value

I have scanned from a command line with "dtvscan -q", starting at channel 78, and get the following messages:

"PAT found ckets" (repeated multiple times)
but also
"Unable to receive valid packets"
I also get "ERROR vct item ptr null couldn't get channel info"

It looks like the cards are picking up the subchannels (both encrypted and unencrypted) that I have seen previously, but they are not able to get the channnel information from them. I think the above-described modulation error with lgdt3303 is probably important, but I don't know how to fix it.

I have searched this forum and the web, and it looks like scanning problems are fairly common recently. I have downloaded the latest v4l-dvb drivers from Mercurial, have tried removing and reinserting the cards, and have modprobed to remove and reinstall cx88-dvb and several other drivers. Nothing seems to work.

Any ideas????
View user's profile Send private message
PostPosted: Sun Apr 08, 2007 11:35 pm Reply with quote
Joined: 12 Feb 2006
Posts: 225

Have you actually compiled and installed the latest drivers from linuxtv.org and they had this problem? Can you set the lgdt330x module's debug parameter to 1 and post the resulting output in dmesg when trying to do a channel scan with mythtv-setup?
View user's profile Send private message
PostPosted: Mon Apr 09, 2007 5:41 am Reply with quote
Joined: 08 Apr 2007
Posts: 5

Yes, I downloaded and compiled the v4l-dvb drivers from linuxtv.org using mercurial by cloning the folder and then running make and make install. (I think I saw your instructions to someone else in this forum on how to do that.) I'm not a Linux expert, but I didn't notice any problems with any of the compiling or installation.

I will post my dmesg results, but I'm not sure how to set the lgdt330x module's debug parameter. (I haven't modprobed lgdt330x separately, but I assume it is loaded automatically. lsmod shows that lgdt330x is present and is used by dvb_core and i2c_core. Should it also be used by cx88_dvb?) Please explain how to run the debug parameter, and I'll let you know the results. By the way, dmesg grepped for lgdt currently doesn't show anything (at least if I haven't scanned channels in mythtv since rebooting). Is that a problem? [b](Edit: I just realized that I need to look for upper case "LGDT". I'll try that later.)[/b]

I should probably also mention that I dropped and reinstalled the mythconverg database in the process of upgrading my system. (I was trying to resolve some NTSC sound and channel-changing issues I had been having and was following a HOWTO posted by another pcHDTV card user in this forum on getting ATSC and NTSC to play nicely.) I don't think that reinstalling mythconverg would have caused my scanning issues, but it's something else to keep in mind. I'm hoping that my recent upgrades will get rid of a "SetInputAndFormat" error I was seeing with NTSC previously. Mythtv was apparently telling the card that it should expect ATSC when it was switching to an analog channel, despite my explicitly defining those channels as NTSC in the channels table. The v4l drivers would freak out and apparently revert to version 1, with a consequent loss of sound fidelity. Let me know if you have any insight on that error as well, in case it comes back when I'm finally able to scan digital channels again.

By the way, thanks for your help![/b]
View user's profile Send private message
Lost the ability to scan digital signals after upgrade
  pcHDTV Forum Index -> Installation/Setup
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
All times are GMT - 7 Hours  
Page 1 of 1  

 Post new topic  Reply to topic  

Powered by phpBB © 2001-2003 phpBB Group
Theme created by Vjacheslav Trushkin