[mythtv-users] Report: Watch out! UB435-Q V2 is NOT the same as UB435-Q

[Jarod Wilson]

On Oct 29, 2010, at 2:37 PM, Devin Heitmueller wrote:

> On Fri, Oct 29, 2010 at 2:04 PM, Jarod Wilson <jarod at wilsonet.com> wrote:
>> On Oct 15, 2010, at 6:07 PM, Jarod Wilson wrote:
>> 
>>> On Fri, Oct 15, 2010 at 12:10 AM, Steven Willoughby <mythtv at thesteve.org> wrote:
>>>> Hello Mr. Wilson,
>>>> 
>>>>    Sorry for breaking the thread, I am new to the list as I just received my
>>>> V2 today.
>>>> 
>>>>    I have applied your patch [1] against the v4l-dvb source tree [2] but it
>>>> doesn't seem to work.  I get the following in dmesg:
>>>> 
>>>>  em28xx video device (1b80:e346): interface 0, class 255 found.
>>>>  em28xx This is an anciliary interface not used by the driver
>>>>  usbcore: registered new interface driver em28xx
>>>>  em28xx driver loaded
>>>> 
>>>>    It is quite possible that I am not testing it right.  I'm new to mythtv.
>>>>  I have tried using mplayer and tvtime but there isn't a /dev/video* device.
>>> 
>>> Nah, I'd expect to see way more spew than that if the stick was
>>> properly brought up, and the 'ancillary' stuff is unexpected. Means
>>> the quick hack patch isn't enough to get it working. Someone with the
>>> stick is going to have to experiment. Or they could guilt me into
>>> working on it by sending me a stick too (though I'm already backlogged
>>> with other hardware I really ought to be working on first...). ;)
>> 
>> So a spot of bad news here... I've been poking at one of Gavin's sticks inside a VM he set up for me, simultaneous with talking to one of the upstream em28xx driver authors. We now have a very good understanding of why the stick isn't working.
>> 
>> All known prior em28xx-based tuner sticks have had at least one isochronous usb endpoint, with a max packet size of 940 bytes, typically. This stick only has bulk usb endpoints and a max packet size of 512. Supporting this stick is actually going to require a fair bit of work in the em28xx driver core to support using bulk transfer instead of isochronous transfer.
>> 
>> Short version: don't buy this stick right now, its going to be a little while before its actually supported.
> 
> Jarod,
> 
> Just an FYI:  bulk support for em2874/em2884 is on my todo list for
> the near future.

Ah, very cool. I'm inclined to wait and let you do that part, since you know em28xx much better than I do, and I'll just focus on the device-specific implementation details (gpio settings, wiring up tuner and demod, etc). I'm assuming you have some other manufacturer's em2874/em2884 based devices to work on this for... :)

-- 
Jarod Wilson
jarod at wilsonet.com