Alan,
The chmod command worked once the execute privileges had been added.
Thus in an emergency for a quick fix that will work until the PC gets
turned off and on again, the following will allow applications with a
simple graphical UI such as Gsbabbel or Viking to download tracks from
the GPS via its USB
sudo chmod 777 /dev/bus/usb -R
For a longer term solution that gives plug and play the udev rules is
the right way to go in this case. For this a text file needs called
51-garmin.rules needs to be placed into the directory
/etc/udev/rules.d
The text file 51-garmin.rules contains the following rule:
ATTR{idVendor}=="091e", ATTR{idProduct}=="0003", MODE="666"
This will set the correct access permissions for the garmin gps to be
accessed via its USB during the system startup.
So far I have not seen any problems with this rule in my installation
of Ubuntu 14.04 LTS when used to download from a Garmin GPSmap 96.
I think this solves my problem. Many thanks for your help and patience
in reading my postings and responding with helpful comments and
suggestions while I struggle with my ignorance of Linux.
Stephen
On Sat, May 14, 2016 at 3:16 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Sat, 14 May 2016, Stephen Furner wrote:
>
>> There seems to be something in addition to just the usb file access
>> priverlages. When I changed them it changed the error message it did
>> not resolve the problem as was expected.
>>
>> I used the following CHMOD command to change the access priverlages
>> for the usb files
>>
>> chmod 666 /dev/bus/usb -R
>
> This command is wrong. It sets the same permissions for the
> directories and the files, but the directories need to have execute
> permission as well.
>
> The permissions on /dev/bus/usb and /dev/bus/usb/* were correct.
> What was wrong was the permissions for /dev/bus/usb/003/003 (or
> whichever file corresponds to the Garmin).
>
> Why haven't you tried installing the /etc/udev/rules.d/ file? This is
> the third time I've told you to do it.
>
>> This gave me rw priverlages on the usb files for all users
>>
>> stephen@stephen-N150P:/$ sudo ls -l dev/bus/usb
>> [sudo] password for stephen:
>> total 0
>> drw-rw-rw- 2 root root 100 May 11 14:39 001
>> drw-rw-rw- 2 root root 80 May 14 03:18 002
>> drw-rw-rw- 2 root root 80 May 12 21:04 003
>> drw-rw-rw- 2 root root 60 May 11 14:39 004
>> drw-rw-rw- 2 root root 60 May 11 14:39 005
>>
>> When I tried to use gebabbel or viking to download the tracks from the
>> gps I got the error message "Found no Garmin USB devices."
>>
>> listing the usb devices does however show it is present.
>>
>> stephen@stephen-N150P:/$ lsusb
>> Bus 001 Device 004: ID 0ac8:c33f Z-Star Microelectronics Corp. Webcam
>> Bus 001 Device 003: ID 0781:5567 SanDisk Corp. Cruzer Blade
>> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
>> Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
>> Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
>> Bus 003 Device 002: ID 0a5c:219c Broadcom Corp.
>> Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
>> Bus 002 Device 005: ID 091e:0003 Garmin International GPS (various models)
>> Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
>>
>>
>> Using gpsbabel on the command line without root privileges to download
>> from the gps also generates the same error message. An strace of
>> gpsbabel provided the following excerpt.
>>
>> openat(AT_FDCWD, "/dev/bus/usb", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3
>> getdents(3, /* 7 entries */, 32768) = 168
>> close(3) = 0
>> openat(AT_FDCWD, "/dev/bus/usb", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3
>> getdents(3, /* 7 entries */, 32768) = 168
>> getdents(3, /* 0 entries */, 32768) = 0
>> close(3) = 0
>> openat(AT_FDCWD, "/dev/bus/usb/005",
>> O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = -1 EACCES (Permission
>> denied)
>> write(2, "Found no Garmin USB devices.\n", 29Found no Garmin USB devices.
>> ) = 29
>> exit_group(1)
>
> That's what happens when a directory doesn't have execute permission.
>
> Alan Stern
>
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