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
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