Re: [linux-uvc-devel] Cannot use webcam under Linux but works under windows

[Pierre D. <pie...@gm...>]

Hi again,

Unfortunately, the seller can not give me the requested information. So I
am stuck to trial and errors or reverse engineering. Could someone point me
in the right direction to solve this problem?

Thanks,

Pierre

On Jan 26, 2018 6:25 AM, "Pierre Daye" <pie...@gm...> wrote:

> Hi Lucas,
>
> First of all, thank you for your quick answer!!
> Unfortunately, it did not work...I will ask the company if there is a
> uvcdynctrl file or if they can tell me which extension units are supported.
> If it doesn't work, is there any way to figure that out using a software
> under Linux or under Windows (as the webcams are working under Windows).
>
> Thanks again,
>
> Pierre
>
> On Jan 25, 2018 6:33 PM, "Lucas Magasweran" <luc...@gm...> wrote:
>
>> Hi Pierre,
>>
>> On Thu, 2018-01-25 at 15:17 +0100, Pierre Daye wrote:
>> > [  157.573136] uvcvideo: Failed to query (GET_DEF) UVC control 13 on
>> > unit 1: -32 (exp. 8).
>>
>> These UVC GET_DEF errors could be causing a problem. Does your camera
>> come with a uvcdynctrl xml file or datasheet that details the supported
>> UVC extension units? The returned size appears to be wrong.
>>
>> Also, try the UVC_QUIRK_PROBE_DEF (0x00000100) quirk and see if that
>> helps.
>>
>> From http://www.ideasonboard.org/uvc/faq/ :
>>
>> UVC_QUIRK_PROBE_DEF: Don't request the video probe and commit default
>> values. Some cameras don't implement the GET_DEF request for the video
>> probe and commit controls, or even completely crash when that request
>> is received. The uvcvideo driver can then use the current values as
>> default values.
>>
>>