[Pkg-phototools-devel] Bug#778916: manual focus still not working, in darktable 1.6.3-1

[Marko Mäkelä]

I just tried the most recent version of darktable from Debian 
experimental (1.6.3-1), and there, the manual focus control does not 
seem to work at all. Immediately before trying the new version, I 
checked with the previously installed 1.6.2-1 that the coarse focus 
control worked.

To try to troubleshoot this a bit further, I started

darktable -d camctl

from the terminal and watched the output. According to the output, 
darktable claims to be trying to execute the commands, but nothing 
happens on the camera:

[camera_control] Starting live view
[camera_control] live view thread started
[camera_control] executing set camera config job eosviewfinder=1
2 fps
[camera_control] Camera configuration change event, lets update internal
configuration cache.
[camera_control] executing set camera config job manualfocusdrive=Far 3

Interestingly, after this experiment, when I try to execute gphoto2 
--shell manually, the focus point refuses to move! This is version 
2.5.4-1, the same version that worked last time. Power-cycling the 
camera (by removing and reinserting the battery) and disconnecting and 
reconnecting the USB cable had no effect. Maybe the Linux end of the USB 
stack is somehow corrupted? But dmesg does not show anything special.

So, it seems that this might be an issue with gphoto2 rather than with 
darktable itself. I guess I could try rebooting Debian and recording the 
output of "gphoto --debug --set-config manualfocusdrive=6", and 
comparing it to the output of the misbehaving session.

Has this issue been forwarded to upstream authors (of darktable or 
gphoto2)?  Could this be some kind of timing glitch or something that 
occasionally works, so that this failure is not seen by the developers 
themselves?

	Marko