Re: (bisected) Logitech C920 (uvcvideo) stutters since 3.9

Grazvydas Ignotas
2014-12-06T00:25:25Z

Hi,

On Fri, Dec 5, 2014 at 1:46 PM, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> Hi Grazvydas,
>
> On Thursday 06 November 2014 00:29:53 Grazvydas Ignotas wrote:
>> On Wed, Nov 5, 2014 at 4:05 PM, Laurent Pinchart wrote:
>> > Would you be able to capture images from the C920 using yavta, with the
>> > uvcvideo trace parameter set to 4096, and send me both the yavta log and
>> > the kernel log ? Let's start with a capture sequence of 50 to 100 images.
>>
>> I've done 2 captures, if that helps:
>> http://notaz.gp2x.de/tmp/c920_yavta/
>>
>> The second one was done using low exposure setting, which allows
>> camera to achieve higher frame rate.
>
> Thank you for the log, they were very helpful. They revealed that the USB SOF
> (Start Of Frame) counter values on the device and host side are not in sync.
> The counters get incremented are very different rates. What USB controller are
> you using ?

00:1d.7 USB controller: Intel Corporation NM10/ICH7 Family USB2 EHCI
Controller (rev 01) (prog-if 20 [EHCI])
Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7592
Flags: bus master, medium devsel, latency 0, IRQ 23
Memory at fe9fbc00 (32-bit, non-prefetchable) [size=1K]
Capabilities: [50] Power Management version 2
Capabilities: [58] Debug port: BAR=1 offset=00a0
Kernel driver in use: ehci-pci

If it helps, I could try on an ARM board, currently don't have any
other x86 hardware around.

--
Gražvydas