Opened 7 years ago
Closed 7 years ago
Last modified 3 years ago
Backport DVB Tuning fixes to 0.19-fixes
|Reported by:||danielk||Owned by:||danielk|
I'd like to take Marcus' comments into account in the tuning. I don't want to use a
300 ms delay for the DVB-T and ATSC cards, since it would slow down tuning quite a bit and make the antenna adjust very slow; but that delay should be fine for DVB-S. I'd also like to incorporate the retuning and the DiSEqC delays. -- dtk
Marcus (March 18th, 2006):
There are several problems that have to be taken into account. First of all, there really are some cards that take up to 4 seconds to tune (mostly DVB-S which also have to switch diseqc). Some cards get confused when you hit the i2c bus too often (i.e. check status) and may not tune in that case.
So what I do is :
1) Set the diseqc and voltage and wait for 10000 usecs. 2) set the frontend 3) wait 300000 usecs check status 4) if you get a has_lock, everything is fine, otherwise repeat step 3 for a couple of times (3 times). 5) If there is still no lock (very rare) repeat 3)+4) 6) still no lock try resetting the diseqc (if there is one) and repeat from 29.
I implemented that in my libdvb and also added a check for tuning times and I got times from 0.2s to 4s for DVB-S cards, always characteristic for the respective card. I did not test many DVB-T cards, but they usually tune much faster.
For some cards the usleeps can be shorter, but I put in values that fit all the cards I could test.
In any case you can forget about the FE_GET_EVENT, this was a relict from the original Nokia API which was made for some specific Nokia API. Most drivers don't implement the events because you would have to implement a polling loop in the driver which you can do just as well with steps 3) and 4).
Change History (11)
comment:1 Changed 7 years ago by danielk
comment:2 Changed 7 years ago by danielk
comment:3 Changed 7 years ago by danielk
comment:4 Changed 7 years ago by danielk
- Milestone changed from 0.20 to 0.19.1
- Summary changed from Revisit DVB Tuning to Backport DVB Tuning fixes to 0.19-fixes
comment:5 Changed 7 years ago by danielk
comment:6 Changed 7 years ago by danielk
comment:7 Changed 7 years ago by danielk
- Resolution set to fixed
- Status changed from new to closed
comment:8 Changed 7 years ago by danielk
comment:9 Changed 7 years ago by dscoular@…
comment:10 Changed 7 years ago by anonymous
- Milestone 0.19.1 deleted
comment:11 Changed 3 years ago by stuartm
- Milestone changed from 0.25 to 0.20