There is a definite problem with the QHY driver not being able to address more than 1 QHY camera using INDI. You must use separate software drivers for the 2 cameras.
This problem, most probably, could be fixed if the authors of KStars or QHY would simply create a subset listing of QHY cameras and allow the user to choose a given copy of the present QHY driver for a given KStars function. The existing driver contains code which identifies many (not all) of the camera models. This is confirmed by the fact, the various EKOS tabs have drop downs allowing the user to select a camera for a given task. The problem is, when a camera is selected for a task, an individual driver is not assigned to that specific camera.
Now, specific to your question on Lin_guider, I assume that you have attempted to connect with Lin_guider remotely using only Lin_guider and it does function correctly?
If Lin_guider does not, then a port, firewall, or issue with Lin_guider's remote access exists.
Sounds like an easy workaround for the problem. So why is nobody acting?
The folks at QHY are primarily working for Windows platforms and dont care
much about Linux. Maybe Jasem will look after that in the next Kstars version?
I think it would be better to isolate the problem.
(I can not shoot a QHY camera, I can not connect with lin_guider.)
Apparently the driver seems to be recognized.
indi Can not shoot even if the exposure of the control panel is changed?
Will it work without problems if only one camera?
Regarding the connection with lin_guider, I put it on another thread.
KStars should allow 1 QHY camera to connect and function normally. In this case, the QHY8L should connect and allow all Ekos image functions. (binning, exposure time, preview)
In order to get to that state, you must have your cameras connected and the QHY8L powered. You must NOT set the Ekos check box which automates the connection process. Start INDI, then using the INDI Control Panel, connect your mount, the QHY8L, and whatever focuser, you might have. If I recall correctly, the QHY driver already included control for QHY filter wheels. In any event, I would focus only on connecting the camera first. You will ignore the QHY5l2 for the time being.
If you connect both and then disconnect one, you are all done. Nothing will work.
Also, I was told today that QHY is working on this problem.