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

[Devin Heitmueller]

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.

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com