2016-09-12 22:38 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
> 2016-09-12 21:57 GMT+03:00 Bin Liu <b-liu@xxxxxx>:
>> Hi,
>>
>> On Mon, Sep 12, 2016 at 11:52:46AM +0300, Matwey V. Kornilov wrote:
>>> 2016-09-12 6:28 GMT+03:00 Bin Liu <b-liu@xxxxxx>:
>>> > Hi,
>>> >
>>> > On Tue, Aug 30, 2016 at 11:44:33PM +0300, Matwey V. Kornilov wrote:
>>> >> 2016-08-30 21:30 GMT+03:00 Bin Liu <b-liu@xxxxxx>:
>>> >> > Hi,
>>> >> >
>>> >> > On Sun, Aug 28, 2016 at 01:13:55PM +0300, Matwey V. Kornilov wrote:
>>> >> >> Hello Bin,
>>> >> >>
>>> >> >> I would like to start new thread on my issue. Let me recall where the issue is:
>>> >> >> There is 100% frame lost in pwc webcam driver due to lots of
>>> >> >> zero-length packages coming from musb driver.
>>> >> >
>>> >> > What is the video resolution and fps?
>>> >>
>>> >> 640x480 YUV420 10 frames per second.
>>> >> pwc uses proprietary compression during device-host transmission, but
>>> >> I don't know how effective it is.
>>> >
>>> > The data rate for VGA YUV420 @10fps is 640x480*1.5*10 = 4.6MB/s, which
>>> > is much higher than full-speed 12Mbps. So the video data on the bus is
>>> > compressed, not YUV420, I believe.
>>> >
>>> >>
>>> >> >
>>> >> >> The issue is present in all kernels (including 4.8) starting from the commit:
>>> >> >>
>>> >> >> f551e13529833e052f75ec628a8af7b034af20f9 ("Revert "usb: musb:
>>> >> >> musb_host: Enable HCD_BH flag to handle urb return in bottom half"")
>>> >> >
>>> >> > What is the behavior without this commit?
>>> >>
>>> >> Without this commit all frames are being received correctly. Single
>>> >
>>> > Which means without this commit your camera has been working without
>>> > issues, and this is a regression with this commit, right?
>>> >
>>>
>>> Right
>>
>> Okay, thanks for confirming.
>>
>> But we cannot just simply add this flag, as it breaks many other use
>> cases. I will continue work on this to find a solution which works on
>> all use cases.
>>
>
> Ok, thank you.
>
Excuse me. Any news?
>> Regards,
>> -Bin.
>>
>
>
>
> --
> With best regards,
> Matwey V. Kornilov.
> Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
> 119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382
--
With best regards,
Matwey V. Kornilov.
Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia
119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382
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