28 replies to this topic

[Gennar1]

It this patch specific for problems in relation with em28xx (as the name suggest) or generic?

Yes, all patches affect only the em28xx driver.

The first one was already merged in the kernel when I started working on it, so my patches depend on it.

The second one is the memory fragmentation fix.

The third one is the fix of the fix (I forgot a piece of code that was causing troubles on some systems).

[Erik Slagter]

Hmmm, sorry, I was under the impression it was a fix for the general memory fragmentation problem on the dm8000 using the 3.2 kernel. I don't think there are many users using dvb sticks on dm8000's...

[reg]

I know at least three guys using this particular USB tuner on DM8000. I agree that that isn't many, but still...

[Erik Slagter]

IIRC this stick uses a em28000 variant that has support starting from recent kernels, not dmm's 3.2 kernel!

[jakey]

As DMM are unlikely to make a DVB-T2 tuner 8000 owners have no choice but to use this tuner for T2 and indeed I use this USB tuner on my 8000, so has the patch been applied ?

[Search40]

I just bought Vu+ Solo2, and i have the PCTV 290e USB, flashed first with Blackhole, it did not work, after with Openpli the same, on Openpli the drivers are there, tried to install them, but it did not let me it was coming up with error, just wondering if this patches has been applied?, i flashed with VIX works great, the tuner show DVB-T2 or DVB-C you can choose, and that the right way because this USB  Support both, VIX has all spot on for this USB, so i will like this to happen with all images, because this is the only DVB-T2 Linux on the Market at the moment, and i like to test few images, spoke with Blackhole team, but no solution has been found there, If it  possible for you to look in to this?, thanks.

[MarkDM]

This is the list of modules you need to install to run the PCTV 290e:

tda18271
cxd2820r
em28xx_dvb
em28xx
v4l2_common
videodev
videobuf_vmalloc
videobuf_core
tveeprom

Is this still necessary with latest release of Open-Pli ?

I bought a PCTV 292e nanostick. I did not find the 290e anymore to buy.

The stick is not detected on my ET5000.

Open pli is latest version , 3.8.7  .

 

I tried "opkg install tda18271"

This command results in errors: "cannot install package tda18271".

What can I do more ? What could be wrong ?

[Dimitrij]

root@et9x00:~# opkg list *tda18271*
kernel-module-tda18271c2dd - 3.8.7-r6.12.7 - tda18271c2dd kernel module  tda18271c2dd kernel module; TDA18271C2 driver

[elpetro]

Finally yesterday night I managed to fix the PCTV 290e driver in order to make it working also in DVB-T mode (DVB-T2 was already working as discussed in the old thread).

I spent quite a bit of time comparing logs, inserting debug code and dumping registers everywhere in the em28xx and cxd2820r driver modules.

In the end, in DVB-T mode the 290e was not able to acquire the lock on the channel due to timing issues. In fact, increasing the wait time from 50 to 200ms in the tuning loop was enough to get the lock on any channel. But channel change was quite slow and sometimes, doing an automatic scan, a frequency was not scanned properly (again for timing issues). So instead of playing with the timings I changed the condition to exit the wait loop from "HAVE_SIGNAL" to "HAVE_LOCK". I think this was the original intention of the driver author (I've asked his feedback on this point).

With this modification, channel scan is 100% reliable and channel change is really fast.

But there was a further issue: a few weak channels were plagued by high BER and badly corrupted pictures. The same channels were working fine on the A867 stick, so I tried to improve the reception.

I noticed that the driver has an option to enable a "Low Noise Amplifier" (LNA) before the demodulator. This LNA is enabled by default for DVB-T2 and DVB-C, but it was disabled for DVB-T.
So I tried to enable it and the reception of weak channels improved a lot!

I collected some data:

LNA OFF:

MUX AGC BER picture

RAI mux 4 72% 32000 corrupted
TIMB 2 75% 14 OK
TVA Vicenza 68% 32000 corrupted
TV7 77% 0 OK
RETE CAPRI 69% 0 OK <------- QPSK modulation!
RAI mux 2 78% 14 OK

LNA ON:

MUX AGC BER picture

RAI mux 4 73% 1500 OK
TIMB 2 76% 0 OK
TVA Vicenza 69% 0 OK
TV7 78% 0 OK
RETE CAPRI 70% 0 OK <------- QPSK modulation!
RAI mux 2 79% 0 OK


So it's clear that the LNA is very useful also for DVB-T reception and should be enabled by default.

In attachment you can find 3 patches. The first one is a collection of all the changes in the em28xx/cxd2820r/tda18271 drivers from kernel 3.1.0 to the latest linux-media drivers available (due for integration in Linux 3.2.0).
This patch adds also support for the PCTV 460e DVB-S2 USB stick. In fact I was too lazy to cherry-pick only the changes relevant to the PCTV 290e, so I just took all changes related to em28xx and dependent drivers. I have no idea if the driver is working or not since I don't have that stick.
The other 2 patches apply the 2 modifications described above (fixed wait loop exit condition and LNA enabled by default).

I think it's better to keep the 2 extra patches separated for the time being, as I don't know if and when they will be integrated in the kernel. I will propose them to the driver author and on the linux-media mailing list.

I'm also including a zip package with the modified modules already compiled (for ET9000).

How can I install this? I am running the latest OpenPLi on my vu duo 2