Hi Logan,

On Wednesday 01 September 2010 16:48:20 Logan Stonebraker wrote:
> Greetings,
> 
> I have been working with Paulo Assis on the quickcamteam forums.
> 
> We have been trying to determine why a Logitech Orbit MP 046d:08c2 is not
> responding to Pan (relative) or Tilt (relative) controls.  Pan/Tilt reset
> and all other Logitech specific controls work splendidly despite this.
> 
> The thread with the details is here:
> http://forums.quickcamteam.net/showthread.php?tid=685
> 
> I noticed on the uvc driver home page http://www.ideasonboard.org/uvc that
> the 046d:08c2 is listed as being compatible with no mention of these
> controls being unusable (albeit potentially unreliable with the footnotes).
> 
> We are unable to get past the camera reporting that it failed to query the
> control.
> 
> Interestingly enough pan and tilt functions work fine on any supported
> Windows OS using available pan/tilt control software.  We are thinking that
> perhaps the reason for this is that the uvcvideo driver expects to query
> these controls prior to setting their values (and fails to read), as
> opposed to the working windows drivers which (perhaps aware of this
> firmware issue) do not query the controls, rather just attempt to set
> their values.

The uvcvideo driver indeed tries to query the controls first. The Windows 
driver, being Logitech-specific, might skip that step.

> dmesg uvcvideo trace=15 on module insertion
> 
>  -snip-
> 
>  [ 1449.492454] USB Video Class driver (v0.1.0)
>  [ 1449.732361] uvcvideo: Control f70c9e90/2 is already defined.
>  [ 1449.741717] uvcvideo: Added control f70c9d90/1 to device 2 entity 9
>  [ 1449.752219] uvcvideo: Added control f70c9e50/2 to device 2 entity 9
>  [ 1449.752259] uvcvideo: Adding mapping Pan (relative) to control
> f70c9d90/1.
>  [ 1449.752278] uvcvideo: Adding mapping Tilt (relative) to control
> f70c9d90/1.
>  [ 1449.752294] uvcvideo: Adding mapping Pan Reset to control f70c9e50/2.
>  [ 1449.752309] uvcvideo: Adding mapping Tilt Reset to control f70c9e50/2.
>  [ 1449.752324] uvcvideo: Adding mapping Pan/tilt Reset to control
> f70c9e50/2.
>  [ 1449.752340] uvcvideo: Adding mapping Focus to control f70c9dd0/3.
>  [ 1449.752355] uvcvideo: Adding mapping LED1 Mode to control f70c9d10/1.
>  [ 1449.752371] uvcvideo: Adding mapping LED1 Frequency to control
> f70c9d10/1.
>  [ 1449.752387] uvcvideo: Adding mapping Disable video processing to
> control f70c9e90/5.
>  [ 1449.752402] uvcvideo: Adding mapping Raw bits per pixel to control
> f70c9fd0/8.
> 
> -snip-
> 
> sudo ./pan /dev/video0 128
>  control(0x009a0904) failed to set (error -1)
> 
> dmesg on attempting to set pan or tilt control (via either usb 1.1 or usb
> 2.0)
>  [3035.732371] uvcvideo: Failed to query (131) UVC control 1 (unit 9) : -32
> (exp. 4).

-32 is -EPIPE, which basically means that your camera failed to answer the 
GET_MAX (131) request on the pan/tilt control (control 1, unit 9). This is 
caused by a timing-related bug in the camera firmware described in footnote 1 
on the website. There's not much I can do about it. According to the messages 
you've posted on the forum, at least one of your test runs showed a different 
behaviour:

 [ 855.955995] uvcvideo: Control 0x009a0900 not found.
 [ 856.003477] uvcvideo: Failed to query (132) UVC control 1 (unit 9) : 1 
(exp. 4).
 [ 856.024605] uvcvideo: Failed to query (132) UVC control 1 (unit 9) : 1 
(exp. 4).
 [ 856.066239] uvcvideo: Control 0x009a0908 not found.

That's also what I get on my computer when I test the pan/tilt controls with 
the same camera. In this case the camera goes past the GET_MAX request, but 
answers the next GET_RES request with only 1 byte of data when the driver 
expect 4. I'll try to get information about that problem from Logitech.

[snip]

> Thank you in advance if you are able to assist in debugging this <or> at
> the very least making mention in a footnote that these specific pan and
> tilt controls could be totally unusable to warn potential 046d:08c2 Orbit
> owners about this issue.

-- 
Regards,

Laurent Pinchart
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