Re: [PATCH] Support for Asus MyCinema U3100Mini Plus (attempt 2)

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On 09/19/12 19:57, Oliver Schinagl wrote:
On 09/19/12 12:41, Antti Palosaari wrote:
On 09/19/2012 12:52 PM, Oliver Schinagl wrote:
On 19-09-12 00:42, Antti Palosaari wrote:
On 09/19/2012 01:22 AM, oliver@xxxxxxxxxxx wrote:
From: Oliver Schinagl <oliver@xxxxxxxxxxx>

This is initial support for the Asus MyCinema U3100Mini Plus. The
driver
in its current form gets detected and loads properly. It uses the
af9035 USB Bridge chip, with an af9033 demodulator. The tuner used is
the FCI FC2580.

I have only done a quick dvb scan, but it failed to tune to anything.
Using dvbv5-scan -I CHANNEL <channelfile> It did show 'signal 100%'
but
failed to tune to anything, so I don't think signal strength works at
all. Since I have really bad reception where my dev PC is, I may
simple
not receive anything here.

Signal strength is very worst indicator. It should not be 100% in any
case. Switch off stupid % meter your are using and look plain numbers.
It is should be something between 0-0xffff (0xffff == 100% ?).
I know 100% says nothing :p and I think especially with this driver? I
didn't see the signal strength function implemented in the FC2580 (I
have some code for it, once I have the device actually working :) But
this is what dvbv5-scan reported.

Have to say have never used tool. Instead w_scan, scan (dvbscan,
scandvb) and tzap. If you get working channels.conf file for your area
you are able to use tzap.
dvbv5-scan is written by Mauro, it comes in the dvb-utils package
together with tzap and dvbscan. It is to utilize the new dvb v5 api.

Both can't find any channels however when scanning. Scanning with my
Terratec Cynergy Dual T PCI-e, I also get 'tuning failed' when scanning
for channels using dvbscan, however I do get a usefull channels.conf
that I can use with tzap on the stick. Unfortunatly, no success.

oliver@valexia ~ $ tzap -c channels.conf "Nederland 1"
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
reading channels from file 'channels.conf'
tuning to 546000000 Hz
video pid 0x1b63, audio pid 0x1b64
status 00 | signal ffff | snr 0000 | ber 00000000 | unc 00000000 |
status 01 | signal ffff | snr 0000 | ber 00000000 | unc 00000000 |

The status blinks to 01 every once in a while, but stays on zero mostly.
"Nederland 1" is a FTA channel that should come in pretty strong.

Of course I tested this all before changing the tuner enable bits. Once
I changed that, well, I had a little party :)

dvbscan still says tuning failed using dvbscan, but it actually finds
all Networks and channels. Also tuning with tzap using a previously
known working channels.conf works. (tzap -r + mplayer) though mplayer
does some weird scaling, which I'm sure is mplayer's fault:
Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
VO: [x11] 704x576 => 1024x576 Planar YV12

Forgot to mention, here's output from tzap when successfully tuning a channel for completness sake. Also note, signal strength is awefully happy at 100% (ffff) which I doubt to be accurate.

status 00 | signal ffff | snr 0000 | ber 00000000 | unc 000001fa |
status 1f | signal ffff | snr 0000 | ber 00000000 | unc 000003de | FE_HAS_LOCK status 1f | signal ffff | snr 00dc | ber 0001d85c | unc 000003e9 | FE_HAS_LOCK status 1f | signal ffff | snr 0104 | ber 0000d1b0 | unc 000003e9 | FE_HAS_LOCK status 1f | signal ffff | snr 0104 | ber 00000000 | unc 000003e9 | FE_HAS_LOCK status 1f | signal ffff | snr 0104 | ber 00000000 | unc 000003e9 | FE_HAS_LOCK




Signal strength is reported by af9033 demodulator regardless if tuner
could report it or not.

For me successful tzap reports (af9035 + tua9001):
status 1f | signal 5eb7 | snr 010e | ber 00000000 | unc 00000000 |
FE_HAS_LOCK

FE_HAS_LOCK is most important, it says demodulator is locked to
channel and likely device is 100% working.
I can't use tzap, as I can't scan for channel file. As I write this, I
remember that I may have one on another system so should be able to use
that to try tonight.

Furthermore, when checking debug while it's running a scan (either
dvbscan or dvbv5-scan) I notice that it passes the loop 5 times, but I
think that's normal from what I can tell from the code. Also
fc2580_get_if_frequency appears to be a stub, correct?

I suspect it tests different parameters. Like one iteration for each
bandwidth. If you know your area transmission parameters you could skip
whole scanning and just waste only two seconds using tzap to test.

fc2580_get_if_frequency is not stub, it is correctly implemented. FC2580
is direct conversion tuner (== zero-IF, IF 0 Hz) which means it
transfers RF band directly to the base-band. No IF used.
Ah, so it is intended to always return zero. It just felt as the debug
information was missing something, as there was a colon, indicating to
show us some output. Maybe always print 0 :)


Biggest problem of your patch is fc2580 frontend callback. fc2580
driver does not use any callback and that code is simple dead. It is
never called.
Ah, assumption eh, I simply thought the callback is always used by the
driver. I noticed some tuners do have the callback, others do their init
just once. What's the cleanest solution, leave the code in the callback,
and call it from fc9035_tuner_attach? (As you otherwise get a huge
tuner_attach function). Anyway, why do some tuners have the callback and
others don't? I guess it's a design decision of the driver, but why
aren't they more equal?

There should not be frontend callback unless needed. The basic (and only
one I know?) use scenario for tuner callback is to control some tuner
external pins using bridge GPIO. If there is no such pins then there is
no need for callback. For example digital AGC you asked earlier is such
control pin (actually 2 pins) but as it is not used no need for
callback. TUA9001 is good example of tuner having control pins.
Since this tuner doesn't have external AGC that we know of, this tuner
shouldn't have a callback. Makes sense.


I think you refer fc0011 tuner callbacks. There seems to be reset and
power. At least power sounds something like it should not be there, I
suspect it is just some GPIO that turns on/off power from tuner and not
control any fc0011 pin.

Antti


Will tidy up my commit and submit it to ML again.

Oliver
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