[linux-uvc-devel] Webcam mode only working with globally disabled USB autosuspend (1f3a:100e)

[Till D. <do...@pr...>]

Hi all,

the device in question is

   Renkforce RF AC4K 300 Action Cam 4K

https://www.conrad.de/de/p/action-cam-renkforce-rf-ac-4k-webcam-4k-wlan-wasserfest-staubgeschuetzt-1577043.html


When connected via USB to a PC, it offers two modes:
  - mass storage
  - camera


When set to webcam mode it identifies as:
   [34367.545510] uvcvideo: Found UVC 1.00 device Android (1f3a:100e)


But in order for the webcam part to work reliably I have to disable USB autosuspend 
(as suggested under https://www.ideasonboard.org/uvc/faq/):

--- snip ---
echo -1 > /sys/module/usbcore/parameters/autosuspend
--- snap ---


With the default value in /sys/module/usbcore/parameters/autosuspend the device 
leaves webcam mode after a few seconds.


So I was wondering whether one can define autosuspend exceptions for certain UVC devices.

Looking through the driver source I didn't discover an obvious way to do so.

Is this something the UVC driver supports?

Or does one have to configure this e.g. via a udev rule when the device is connected?


Any hints are appreciated.


Thanks and regards -- Till
-- 
Dipl.-Inform. Till Dörges                  do...@pr...
PRESENSE Technologies GmbH             Nagelsweg 41, D-20097 HH
Geschäftsführer/Managing Directors       AG Hamburg, HRB 107844
Till Dörges, Jürgen Sander               USt-IdNr.: DE263765024