My ASI-1600MM-Cool camera regularly locks up while downloading an image.
The INDI control panel then shows a yellow expose light and ever changing remaining download times. syslog shows no camera disconnects.

The ASI-1600MM-Cool camera is connected to a 4A powered USB3 HUB which is connected to a USB2 port on a laptop.
It also has a 12V/2A power supply for its cooler but the issue I have is independent of cooler use.
I know the ideal setup is to directly connect to a USB3 port on the computer, but this is not yet available on this system (I may get a USB3 express card).

When connecting the camera to the USB2 port on a laptop all looks fine at first, but on any image download the entire device immediately gets disconnected from the USB bus. I assume this is because of too high power use, hence the powered USB3 HUB. No more USB bus disconnects, but a new problem instead.

I've read advice for the ASCOM world about lowering the transfer speed for USB2 setups. Can this be done with INDI too ? Is it needed ?

I found nothing relevant in driver debug log file, just lines like
DEBUG 1319.690531 sec : StartExposure->setexp : 0.500s

Ubuntu 16.04 , kstars-bleeding 5:16.10+201610151447~ubuntu16.04.1 , indi-asi 0.5+r2651~201610151451~ubuntu16.04.1

Any hints on how to debug this issue ?

-- Hans

latest kstars 5:16.10+201610221517~ubuntu16.04.1 and indi 0.5+r2661~201610221453~ubuntu16.04.1 from -bleeding debug shows this :

DEBUG 286.299384 sec : StartExposure->setexp : 1.000s
DEBUG 288.435937 sec : ASIGetExpStatus failed (0). Restarting exposure...
DEBUG 288.536090 sec : StartExposure->setexp : 1.000s
DEBUG 290.689925 sec : ASIGetExpStatus failed (0). Restarting exposure...
DEBUG 290.790078 sec : StartExposure->setexp : 1.000s
DEBUG 292.943371 sec : ASIGetExpStatus failed (0). Restarting exposure...

Yes USB bandwidth can be the issue with a slower host computer.
You can try lowering the USB bandwidth from the last tab in the indi control panel. it should be 80 by default. Try 60 or 50...

Rumen

Confirmed. INDI Control Panel -> Controls tab -> change Bandwidth from 80 to 70 and click 'Set' and frames can be downloaded without issue.
Proposal: With the current auto-retry-forever we might want to lower the Bandwidth automatically until things starts working.

A pull request for this, and your other requested feature (for image format saving) is appreciated