Re: pwc over musb: 100% frame drop (lost) on high resolution stream

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I've just checked 4.8-rc2 - same behaviour.

2016-08-18 16:31 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
> Any ideas?
>
> 2016-08-04 23:08 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>> When DMA is not used, I see the same behavior: lots of zero-length
>> packages received.
>>
>> Can It be related to some kind of USB overflow due to long input data
>> processing with disabled IRQ?
>> When HCD_BC is used then part of processing is postponed and this can
>> explain greater throughput due to better latency.
>>
>> 2016-08-04 22:58 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>> I've just found that in such cases, when DMA actual length is zero,
>>> both cppi41_channel->prog_len and txstate.residue equal 960 at
>>> musb_cppi41 line 225:
>>>
>>> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/usb/musb/musb_cppi41.c#n225
>>>
>>> 2016-08-04 22:08 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>>> I've just found that dma->actual_len equals to zero in most cases at
>>>> musb_host.c line 1946.
>>>> And this produces zero-length packages.
>>>>
>>>> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/usb/musb/musb_host.c#n1946
>>>>
>>>> Any ideas why?
>>>>
>>>> 2016-08-04 19:57 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>>>> I've just found that many packages in URBs have zero actual_length (It
>>>>> is a question why).
>>>>> Then the following end of frame criteria leads to `frame underflow' message:
>>>>>
>>>>>                 if (flen < pdev->vlast_packet_size) {
>>>>>                         /* Shorter packet... end of frame */
>>>>>                         if (pdev->vsync == 2)
>>>>>                                 pwc_frame_complete(pdev);
>>>>>                         if (pdev->fill_buf == NULL)
>>>>>                                 pdev->fill_buf = pwc_get_next_fill_buf(pdev);
>>>>>                         if (pdev->fill_buf) {
>>>>>                                 pdev->fill_buf->filled = 0;
>>>>>                                 pdev->vsync = 1;
>>>>>                         }
>>>>>                 }
>>>>>
>>>>> 2016-08-01 21:16 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>>>>> pwc module output with trace=511 is the following:
>>>>>>
>>>>>> [   24.793109] usbcore: registered new interface driver Philips webcam
>>>>>> [   29.276979] pwc: Unsupported pixel format
>>>>>> [   29.277055] pwc: pwc_vidioc_fill_fmt() width=640, height=480,
>>>>>> bytesperline=640, sizeimage=460800, pixelformat=YU12
>>>>>> [   29.277090] pwc: Trying to set format to: width=640 height=480
>>>>>> fps=15 format=YU12
>>>>>> [   29.277123] pwc: set_video_mode(640x480 @ 30, pixfmt 32315559).
>>>>>> [   29.277145] pwc: decode_size = 5.
>>>>>> [   29.277180] pwc: frame_size=63120, vframes=15, vsize=5, vbandlength=526
>>>>>> [   29.277204] pwc: Set resolution to 640x480
>>>>>> [   29.277225] pwc: pwc_set_video_mode(), return=0
>>>>>> [   29.277256] pwc: pwc_vidioc_fill_fmt() width=640, height=480,
>>>>>> bytesperline=640, sizeimage=460800, pixelformat=YU12
>>>>>> [   29.277306] pwc: ioctl(VIDIOC_G_FMT) return size 640x480
>>>>>> [   29.277337] pwc: pwc_vidioc_fill_fmt() width=640, height=480,
>>>>>> bytesperline=640, sizeimage=460800, pixelformat=YU12
>>>>>> [   29.277449] pwc: set_video_mode(640x480 @ 10, pixfmt 32315559).
>>>>>> [   29.277475] pwc: decode_size = 5.
>>>>>> [   29.278726] pwc: frame_size=94560, vframes=10, vsize=5, vbandlength=788
>>>>>> [   29.278750] pwc: Set resolution to 640x480
>>>>>> [   29.300374] pwc: set_video_mode(640x480 @ 10, pixfmt 32315559).
>>>>>> [   29.300420] pwc: decode_size = 5.
>>>>>> [   29.441759] pwc: frame_size=94560, vframes=10, vsize=5, vbandlength=788
>>>>>> [   29.441792] pwc: Set resolution to 640x480
>>>>>> [   29.441824] pwc: Setting alternate interface 9
>>>>>> [   29.455061] pwc: Allocated URB at 0xc9b83600
>>>>>> [   29.455850] pwc: Allocated URB at 0xc9b83400
>>>>>> [   29.456040] pwc: Allocated URB at 0xc9b83200
>>>>>> [   29.456271] pwc: URB 0xc9b83600 submitted.
>>>>>> [   29.456310] pwc: URB 0xc9b83400 submitted.
>>>>>> [   29.456341] pwc: URB 0xc9b83200 submitted.
>>>>>> [   29.456362] pwc: << pwc_isoc_init()
>>>>>> [   30.078550] pwc: Frame buffer underflow (20076 bytes); discarded.
>>>>>> [   30.170543] pwc: Frame buffer underflow (12428 bytes); discarded.
>>>>>> [   30.272538] pwc: Frame buffer underflow (14340 bytes); discarded.
>>>>>> [   30.374541] pwc: Frame buffer underflow (16252 bytes); discarded.
>>>>>> [   30.476535] pwc: Frame buffer underflow (18164 bytes); discarded.
>>>>>> [   30.578532] pwc: Frame buffer underflow (20076 bytes); discarded.
>>>>>> [   30.670538] pwc: Frame buffer underflow (12428 bytes); discarded.
>>>>>> [   30.772544] pwc: Frame buffer underflow (14340 bytes); discarded.
>>>>>> [   30.874547] pwc: Frame buffer underflow (16252 bytes); discarded.
>>>>>> [   30.976552] pwc: Frame buffer underflow (18164 bytes); discarded.
>>>>>> [   31.078536] pwc: Frame buffer underflow (20076 bytes); discarded.
>>>>>> [   31.170533] pwc: Frame buffer underflow (12428 bytes); discarded.
>>>>>> [   31.272549] pwc: Frame buffer underflow (14340 bytes); discarded.
>>>>>> [   31.374545] pwc: Frame buffer underflow (16252 bytes); discarded.
>>>>>> [   31.476537] pwc: Frame buffer underflow (18164 bytes); discarded.
>>>>>> [   31.578536] pwc: Frame buffer underflow (20076 bytes); discarded.
>>>>>> [   31.660895] pwc: Frame buffer underflow (11472 bytes); discarded.
>>>>>> [   31.772554] pwc: Frame buffer underflow (14340 bytes); discarded.
>>>>>> [   31.874548] pwc: Frame buffer underflow (16252 bytes); discarded.
>>>>>> [   31.976533] pwc: Frame buffer underflow (18164 bytes); discarded.
>>>>>>
>>>>>>
>>>>>> 2016-07-31 23:31 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>>>>>> Hello,
>>>>>>>
>>>>>>> I've also just found that the same commit breaks cpufreq on BeagleBone Black :)
>>>>>>>
>>>>>>> So, probably without HCD_BH flag musb works correctly only at 1Ghz CPU
>>>>>>> frequency, which is unlisted and being set to 720Mhz by cpufreq driver
>>>>>>> (as it did whet there was cpufreq driver).
>>>>>>>
>>>>>>> 2016-07-29 21:01 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> I've found that the following commit fixes the issue:
>>>>>>>>
>>>>>>>> commit 7694ca6e1d6f01122f05039b81f70f64b1ec4063
>>>>>>>> Author: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
>>>>>>>> Date:   Fri Apr 22 16:58:42 2016 +0530
>>>>>>>>
>>>>>>>>     cpufreq: omap: Use generic platdev driver
>>>>>>>>
>>>>>>>>     The cpufreq-dt-platdev driver supports creation of cpufreq-dt platform
>>>>>>>>     device now, reuse that and remove similar code from platform code.
>>>>>>>>
>>>>>>>>
>>>>>>>> 2016-07-28 19:16 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>>>>>>>> Hello,
>>>>>>>>>
>>>>>>>>> I've just bisected commit, which fixed the issue in v4.7
>>>>>>>>>
>>>>>>>>> commit 9fa64d6424adabf0e3a546ae24d01a62a927b342
>>>>>>>>> Merge: f55532a febce40
>>>>>>>>> Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>>>>>>>>> Date:   Sat Apr 2 01:07:17 2016 +0200
>>>>>>>>>
>>>>>>>>>     Merge back intel_pstate fixes for v4.6.
>>>>>>>>>
>>>>>>>>>     * pm-cpufreq:
>>>>>>>>>       intel_pstate: Avoid extra invocation of intel_pstate_sample()
>>>>>>>>>       intel_pstate: Do not set utilization update hook too early
>>>>>>>>>
>>>>>>>>> Unfortunately, intel_pstate branch doesn't have
>>>>>>>>> f551e13529833e052f75ec628a8af7b034af20f9 applied.
>>>>>>>>> I'll try to bisect this branch with the patch manually applied.
>>>>>>>>>
>>>>>>>>> 2016-07-27 20:34 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>>>>>>>>> Hello,
>>>>>>>>>>
>>>>>>>>>> I've just biseced commit, which introduced this issue
>>>>>>>>>>
>>>>>>>>>> commit f551e13529833e052f75ec628a8af7b034af20f9
>>>>>>>>>> Author: Bin Liu <b-liu@xxxxxx>
>>>>>>>>>> Date:   Mon Apr 25 15:53:30 2016 -0500
>>>>>>>>>>
>>>>>>>>>>     Revert "usb: musb: musb_host: Enable HCD_BH flag to handle urb
>>>>>>>>>> return in bottom half"
>>>>>>>>>>
>>>>>>>>>> I have not checked yet, if it was intentionnaly fixed.
>>>>>>>>>>
>>>>>>>>>> 2016-07-23 22:24 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>>>>>>>>>> 2016-07-20 21:56 GMT+03:00 Matwey V. Kornilov <matwey@xxxxxxxxxx>:
>>>>>>>>>>>> 2016-07-20 18:06 GMT+03:00 Bin Liu <b-liu@xxxxxx>:
>>>>>>>>>>>>> Hi,
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Wed, Jul 20, 2016 at 05:44:56PM +0300, Matwey V. Kornilov wrote:
>>>>>>>>>>>>>> 2016-07-20 17:13 GMT+03:00 Bin Liu <b-liu@xxxxxx>:
>>>>>>>>>>>>>> > Hi,
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> > On Wed, Jul 20, 2016 at 09:09:42AM +0300, Matwey V. Kornilov wrote:
>>>>>>>>>>>>>> >> 2016-07-20 0:34 GMT+03:00 Bin Liu <b-liu@xxxxxx>:
>>>>>>>>>>>>>> >> > Hi,
>>>>>>>>>>>>>> >> >
>>>>>>>>>>>>>> >> > On Wed, Jul 20, 2016 at 12:25:44AM +0300, Matwey V. Kornilov wrote:
>>>>>>>>>>>>>> >> >> 2016-07-19 23:56 GMT+03:00 Bin Liu <b-liu@xxxxxx>:
>>>>>>>>>>>>>> >> >> > Hi,
>>>>>>>>>>>>>> >> >> >
>>>>>>>>>>>>>> >> >> > On Tue, Jul 19, 2016 at 11:21:17PM +0300, matwey@xxxxxxxxxx wrote:
>>>>>>>>>>>>>> >> >> >> Hello,
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> I have Philips SPC 900 camera (0471:0329) connected to my AM335x based BeagleBoneBlack SBC.
>>>>>>>>>>>>>> >> >> >> I am sure that both of them are fine and work properly.
>>>>>>>>>>>>>> >> >> >> I am running Linux 4.6.4 (my kernel config is available at https://clck.ru/A2kQs ) and I've just discovered, that there is an issue with frame transfer when high resolution formats are used.
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> The issue is the following. I use simple v4l2 example tool (taken from API docs), which source code is available at http://pastebin.com/grcNXxfe
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> When I use (see line 488) 640x480 frames
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >>                 fmt.fmt.pix.width       = 640;
>>>>>>>>>>>>>> >> >> >>                 fmt.fmt.pix.height      = 480;
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> then I get "select timeout" and don't get any frames.
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> When I use 320x240 frames
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >>                 fmt.fmt.pix.width       = 320;
>>>>>>>>>>>>>> >> >> >>                 fmt.fmt.pix.height      = 240;
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> then about 60% frames are missed. An example outpout of ./a.out -f is available at https://yadi.sk/d/aRka8xWPtSc4y
>>>>>>>>>>>>>> >> >> >> It looks like there are pauses between bulks of frames (frame counter and timestamp as returned from v4l2 API):
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> 3 3705.142553
>>>>>>>>>>>>>> >> >> >> 8 3705.342533
>>>>>>>>>>>>>> >> >> >> 13 3705.542517
>>>>>>>>>>>>>> >> >> >> 110 3708.776208
>>>>>>>>>>>>>> >> >> >> 115 3708.976190
>>>>>>>>>>>>>> >> >> >> 120 3709.176169
>>>>>>>>>>>>>> >> >> >> 125 3709.376152
>>>>>>>>>>>>>> >> >> >> 130 3709.576144
>>>>>>>>>>>>>> >> >> >> 226 3712.807848
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> When I use tiny 160x120 frames
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >>                 fmt.fmt.pix.width       = 160;
>>>>>>>>>>>>>> >> >> >>                 fmt.fmt.pix.height      = 120;
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> then more frames are received. See output example at https://yadi.sk/d/DedBmH6ftSc9t
>>>>>>>>>>>>>> >> >> >> That is why I thought that everything was fine in May when used tiny xawtv window to check kernel OOPS presence (see http://www.spinics.net/lists/linux-usb/msg141188.html for reference)
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> Even more. When I introduce USB hub between the host and the webcam, I can not receive even any 320x240 frames.
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> I've managed to use ftrace to see what is going on when no frames are received.
>>>>>>>>>>>>>> >> >> >> I've found that pwc_isoc_handler is called frequently as the following:
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >>  0)               |  pwc_isoc_handler [pwc]() {
>>>>>>>>>>>>>> >> >> >>  0)               |    usb_submit_urb [usbcore]() {
>>>>>>>>>>>>>> >> >> >>  0)               |      usb_submit_urb.part.3 [usbcore]() {
>>>>>>>>>>>>>> >> >> >>  0)               |        usb_hcd_submit_urb [usbcore]() {
>>>>>>>>>>>>>> >> >> >>  0)   0.834 us    |          usb_get_urb [usbcore]();
>>>>>>>>>>>>>> >> >> >>  0)               |          musb_map_urb_for_dma [musb_hdrc]() {
>>>>>>>>>>>>>> >> >> >>  0)   0.792 us    |            usb_hcd_map_urb_for_dma [usbcore]();
>>>>>>>>>>>>>> >> >> >>  0)   5.750 us    |          }
>>>>>>>>>>>>>> >> >> >>  0)               |          musb_urb_enqueue [musb_hdrc]() {
>>>>>>>>>>>>>> >> >> >>  0)   0.750 us    |            _raw_spin_lock_irqsave();
>>>>>>>>>>>>>> >> >> >>  0)               |            usb_hcd_link_urb_to_ep [usbcore]() {
>>>>>>>>>>>>>> >> >> >>  0)   0.792 us    |              _raw_spin_lock();
>>>>>>>>>>>>>> >> >> >>  0)   0.791 us    |              _raw_spin_unlock();
>>>>>>>>>>>>>> >> >> >>  0) + 10.500 us   |            }
>>>>>>>>>>>>>> >> >> >>  0)   0.791 us    |            _raw_spin_unlock_irqrestore();
>>>>>>>>>>>>>> >> >> >>  0) + 25.375 us   |          }
>>>>>>>>>>>>>> >> >> >>  0) + 45.208 us   |        }
>>>>>>>>>>>>>> >> >> >>  0) + 51.042 us   |      }
>>>>>>>>>>>>>> >> >> >>  0) + 56.084 us   |    }
>>>>>>>>>>>>>> >> >> >>  0) + 61.292 us   |  }
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> However, pwc_isoc_handler never calls vb2_buffer_done() that is why I get "select timeout" in userspace.
>>>>>>>>>>>>>> >> >> >> Unfortunately, my kernel is not compiled with CONFIG_USB_PWC_DEBUG=y but I can recompile it, if you think that it could provide more information. I am also ready to perform additional tests (use usbmon maybe?).
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> How could this issue be resolved?
>>>>>>>>>>>>>> >> >> >>
>>>>>>>>>>>>>> >> >> >> Thank you.
>>>>>>>>>>>>>> >> >> >
>>>>>>>>>>>>>> >> >> > Do you have CPPI DMA enabled? If so I think you might hit on a known
>>>>>>>>>>>>>> >> >> > issue in CPPI Isoch transfer, in which the MUSB controller only sends IN
>>>>>>>>>>>>>> >> >> > tokens in every other SOF, so only half of the bus bandwidth is
>>>>>>>>>>>>>> >> >> > utilized, which causes video frame drops in higher resolution.
>>>>>>>>>>>>>> >> >> >
>>>>>>>>>>>>>> >> >>
>>>>>>>>>>>>>> >> >> Yes, I do use DMA:
>>>>>>>>>>>>>> >> >>
>>>>>>>>>>>>>> >> >> CONFIG_USB_TI_CPPI41_DMA=y
>>>>>>>>>>>>>> >> >
>>>>>>>>>>>>>> >> > Okay.
>>>>>>>>>>>>>> >> >
>>>>>>>>>>>>>> >> >>
>>>>>>>>>>>>>> >> >> > To confirm this, use a bus analyzer to capture a bus trace, you would
>>>>>>>>>>>>>> >> >> > see no IN tokens in every other SOF while transfering Isoch packets.
>>>>>>>>>>>>>> >> >> >
>>>>>>>>>>>>>> >> >>
>>>>>>>>>>>>>> >> >> I am sorry, I am new to USB debugging. Do you mean I need to use
>>>>>>>>>>>>>> >> >> usbmon or some external hardware device?
>>>>>>>>>>>>>> >> >
>>>>>>>>>>>>>> >> > I barely use usbmon, and not sure if it gives the information I am
>>>>>>>>>>>>>> >> > looking for. But I meant the external test equipment - USB bus protocol
>>>>>>>>>>>>>> >> > analyzer - a bus packet sniffer.
>>>>>>>>>>>>>> >> >
>>>>>>>>>>>>>> >>
>>>>>>>>>>>>>> >> Now I see. I've googled it, they start from $1000, I don't know
>>>>>>>>>>>>>> >> when/whether/where I can get one to try.
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> > I think you might be able to check it without a sniffer - MUSB
>>>>>>>>>>>>>> > controller can generate SOF interrupts, but it is masked in current
>>>>>>>>>>>>>> > driver. So I think you could enable SOF interrupt, then if you get a log
>>>>>>>>>>>>>> > as
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >         ...
>>>>>>>>>>>>>> > or
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >         ...
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> > which means your issue is different from the one I mentioned. But if
>>>>>>>>>>>>>> > you get a log as
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >         SOF     <--- no rx packets in two consecutive SOFs
>>>>>>>>>>>>>> >         rx packet
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >         SOF
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> > then you hit on the known issue I mentioned.
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> >> Until that, could I check something else? For instance, disable
>>>>>>>>>>>>>> >> CONFIG_USB_TI_CPPI41_DMA.
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> > You could disable it, but I don't think you will get yuv video stream
>>>>>>>>>>>>>> > of 640x480@30fps. PIO mode does not support such high bandwidth. What is
>>>>>>>>>>>>>> > your video requirement anyway?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Many thanks for your guidance. I will answer the rest later when will
>>>>>>>>>>>>>> be ready to play with SOF interrupt.
>>>>>>>>>>>>>> Now, I would like to say that use_dma=0 doesn't change the behaviour:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> # cat /sys/module/musb_hdrc/parameters/use_dma
>>>>>>>>>>>>>> N
>>>>>>>>>>>>>
>>>>>>>>>>>>> It sounds like you have a different issue here. With usb_dma=0, I
>>>>>>>>>>>>> remembered I can get 320x240 YUV stream @30fps from uvc cameras.
>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I would like 640x480@5fps which works with x86 based PC. Issue here,
>>>>>>>>>>>>>> that I can not obtain 640x480 at any FPS on musb.
>>>>>>>>>>>>>
>>>>>>>>>>>>> The current CPPI41 driver should be able to handle this. I think you
>>>>>>>>>>>>> really have to debug the pwc driver to figure out why it drops the video
>>>>>>>>>>>>> frame. I personally don't have a pwc supported camera, never looked the
>>>>>>>>>>>>> pwc driver...
>>>>>>>>>>>>
>>>>>>>>>>>> Surprisingly, I've found that my 10-year-old laptop (Intel Core Solo
>>>>>>>>>>>> T1350) has the similar issue with pwc (kernel 3.16). It drops 80% of
>>>>>>>>>>>> 640x480 frames.
>>>>>>>>>>>> Vortex86 200Mhz based rugged PC with 2.6.14 works fine.
>>>>>>>>>>>> Quad-code Atom E3800 based PC with 4.1 also works fine.
>>>>>>>>>>>>
>>>>>>>>>>>> So, I even don't know what to say. Probably, the issue depends on CPU
>>>>>>>>>>>> latency/performance and it was there for a while.
>>>>>>>>>>>> Fortunately, I think, I could use git bisect if I found latest forking
>>>>>>>>>>>> kernel for my laptop.
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> It seems that the issue is gone in 4.7-rc7, so forget it.
>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> >>
>>>>>>>>>>>>>> >> I've found that after hours of transmit, the camera stops iso at all
>>>>>>>>>>>>>> >> (until reset). Maybe its brain becomes damaged by the transfer issues
>>>>>>>>>>>>>> >
>>>>>>>>>>>>>> > How did you check that? MUSB stopped generating RX EP interrupt?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Something like that, I suppose. Normally, I see input data flow in
>>>>>>>>>>>>>> usbmon, but don't see frames in v4l2.
>>>>>>>>>>>>>> But when camera 'hungs', I don't see nor input flow (except the
>>>>>>>>>>>>>> control packages exchange) neither frames.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Fair enough.
>>>>>>>>>>>>>
>>>>>>>>>>>>> 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
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> 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
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> 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
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> 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
>>>>
>>>>
>>>>
>>>> --
>>>> 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
>>
>>
>>
>> --
>> 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



-- 
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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