Re: WinTV-HVR-1400: scandvb (and kaffeine) fails to find any channels

[Chris Clayton <chris2553@googlemail.com>]

Hi Devin,

On 02/01/13 14:19, Devin Heitmueller wrote:
> On Fri, Feb 1, 2013 at 9:16 AM, Chris Clayton <chris2553@googlemail.com> wrote:
>> I've got some more diagnostics. I tuned on the 12c debugging in the cx23885
>> driver and ran the scan again. Surprisingly, the scan found 22 channels on a
>> single frequency (that carries the BBC channels). I've attached two files -
>> the output from dvbscan and the kernel log covering the loading of the
>> drivers and running the scan.
>>
>> I'm no kernel guru, but is it possible that the root cause of the scan
>> failures is a timing problem which is being partially offset by the time
>> taken to produce all the debug output?
>
> w_scan does have some arguments that let you increase the timeout for
> tuning.  You may wish to see if that has any effect.  Maybe the w_scan
> timeout is just too short for that device.
>

Yes, I noticed that but even with the tuning timeout set at medium or 
longest, I doesn't find any channels. However, I've been following the 
debug messages through the code and ended up at 
drivers/media/pci/cx23885/cx23885-i2c.c.

I've found that by amending I2C_WAIT_DELAY from 32 to 64, I get improved 
results from scanning. With that delay doubled, scandvb now finds 49 
channels over 3 frequencies. That's with all debugging turned off, so no 
extra delays provided by the production of debug messages.

I'll play around more tomorrow and update then.

Chris

> Devin
>