Here are some of troubleshooting results. Computer is connected using USB port (computer) to USB/B type port on the mount
side.
fuser -k /dev/ttyUSB0. : Shows no output, before or after Ekos/Indi startup. (I would expect pid of some process, if busy using it, but nothing shows up)
lsof | grep -i usb0 : Shows no output, before or after Ekos/Indi startup. (I would expect process details, if using it)
I also captured the strace for the runnng indi_eqmod_telescope process and then hit connect several times. stace gave the following output.
$ sudo strace -fp 2686
strace: Process 2686 attached
pselect6(1, [0], NULL, NULL, NULL, NULL
) = 1 (in [0])
read(0, "<newSwitchVector device=\"EQMod M"..., 2048) = 127
openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_CLOEXEC) = -1 EBUSY (Device or resource busy)
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=1, tv_nsec=0}, NULL) = 0
openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_CLOEXEC) = -1 EBUSY (Device or resource busy)
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=1, tv_nsec=0}, NULL) = 0
openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_CLOEXEC) = -1 EBUSY (Device or resource busy)
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=1, tv_nsec=0}, NULL) = 0
sendmsg(1, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="<?xml version='1.0'?>\n<message\n "..., iov_len=176}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 176
sendmsg(1, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="<?xml version='1.0'?>\n<setSwitch"..., iov_len=278}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 278
pselect6(1, [0], NULL, NULL, NULL, NULL) = 1 (in [0])
read(0, "<newSwitchVector device=\"EQMod M"..., 2048) = 381
openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_CLOEXEC) = -1 EBUSY (Device or resource busy)
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=1, tv_nsec=0}, NULL) = 0
openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_CLOEXEC) = -1 EBUSY (Device or resource busy)
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=1, tv_nsec=0}, NULL) = 0
openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_CLOEXEC) = -1 EBUSY (Device or resource busy)
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=1, tv_nsec=0}, NULL) = 0
sendmsg(1, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="<?xml version='1.0'?>\n<message\n "..., iov_len=176}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 176
sendmsg(1, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="<?xml version='1.0'?>\n<setSwitch"..., iov_len=278}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 278
openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_CLOEXEC) = -1 EBUSY (Device or resource busy)
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=1, tv_nsec=0}, NULL) = 0
openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_CLOEXEC) = -1 EBUSY (Device or resource busy)
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=1, tv_nsec=0}, NULL) = 0
openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_CLOEXEC) = -1 EBUSY (Device or resource busy)
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=1, tv_nsec=0}, NULL) = 0
I have also updated the Mount firmware (latest at this time: 3.39.25). No change, same error. Not sure what else to try.
For now I am able to use the following two options. Reasonable options for me. Direct USB would still be good to have.
(Option-1) Connect computer USB cable via Synscan Hand-controller and use 'PC Direct Mode' on the hand-controller. Hand-controller is connected to the mount via RJ-45 port. On computer with Indi panel using EQMOD mount driver with Baud rate:9600. /dev/ttyUSB0 works fine in this case. "fuser -k /dev/ttyUSB0" command shows pid of the indi_eqmod_telescope process.
(Option-2) Using Synscan WiFI dongle and Indi connected via Dongle. Using 'Network IP address of the dongle" / Port : 11880/ UDP EQMOD mount driver, This works as well. Computer/Indi server then able to connect to the mount through wifi dongle.
