[Lubuntu] How to unmount a camera from the command line?

John Hupp lubuntu at prpcompany.com
Sat Nov 3 00:02:16 UTC 2012 

Despite what I wrote below, I had the further thought that, "Yes, I 
would like to know how to write udev rules, and if I can find a 
well-written how-to, then I'll move ahead."

And indeed, I believe I found such a document at 
http://www.reactivated.net/writing_udev_rules.html

But after plowing through the whole thing, I encountered this mysterious 
warning in his USB Camera section:

    Like most, my camera identifies itself as an external hard disk
    connected over the USB bus, using the SCSI transport. To access my
    photos, I mount the drive and copy the image files onto my hard disk.

    Not all cameras work in this way: some of them use a non-storage
    protocol such as cameras supported by gphoto2. In the gphoto case,
    you do not want to be writing rules for your device, as is it
    controlled purely through userspace (rather than a specific kernel
    driver).

Though I don't understand what he was saying about userspace, I observe 
that pcmanfm displays the camera files locationas 
gphoto2://[usb:003,004] rather than a usual device or file system path. 
Plus /dev/disk seems to have no reference to the camera memory.

Does this seem like a udev rule show-stopper when it comes to solving 
this problem?

On 11/2/2012 12:06 PM, John Hupp wrote:
> Phill, I posted in the UbuntuForums at 
> http://ubuntuforums.org/showthread.php?p=12333141#post12333141.  And 
> yes, this Canon Powershot G1 is a digital camera with built-in memory 
> which is being auto-mounted as as file system at 
> gphoto2://[usb:003,004]. The Wikiinfo that applies to your webcam does 
> not apply to my Canon. (There is no /dev/video*, for instance).
>
> Steve, you suggested that I look at writing udev rules for the 
> camera.  So I read up on the topic at 
> http://manpages.ubuntu.com/manpages/karmic/en/man7/udev.7.html, but I 
> have not yet found a way to apply that. Somewhere there is probably 
> further reading that would tell me how to locate the rule that causes 
> the camera auto-mount, but just taking a guess that the governing rule 
> file was /lib/udev/rules.d/40-libgphoto2-2.rules (since the camera 
> mounts as gphoto2://[usb:003,004]), I didn't see any rule that would 
> govern auto-mount.
>
> I could attach 40-libgphoto2-2.rules if anyone wants to see it, but 
> it's 179KB.
>
> So unless I can get some pointed advice on where to locate the rule of 
> interest, it looks to me like trying to write a udev rule-- while an 
> appealing and compliant approach-- would be jumping down a pretty deep 
> rabbit hole for me. (I mean deeper than the one I've already jumped down.)
>
> On 11/2/2012 5:44 AM, Yorvyk wrote:
>> On 02/11/12 01:10, Phill Whiteside wrote:
>>> Hi John,
>>>
>>> I've found my little minicom usb camera / mic device. It does not get
>>> mounted by PCManFM, but does appear if I check
>>>
>>> phillw at piglet:~$ ls /dev/video*
>>> /dev/video0
>>>
>>> Which changes to
>>>
>>> phillw at piglet:~$ ls /dev/video*
>>> /dev/video0  /dev/video1
>>>
>>> when I plug it in.
>>>
>>> I suspect that as my device is a real dumb web-cam, has yours got in
>>> built memory? If it has, then that would explain it being mounted as a
>>> storage device.
>>>
>>> I'm following the hints and tips from the wiki area [1] The Multimedia
>>> guys on the forum are far better placed to assist you[2].
>>>
>>> Regards,
>>>
>>> Phill.
>>> 1. https://help.ubuntu.com/community/Webcam#Configuring_Webcam_Software
>>> 2. http://ubuntuforums.org/forumdisplay.php?f=334
>>>
>>>
>>> On 1 November 2012 23:59, John Hupp <lubuntu at prpcompany.com
>>> <mailto:lubuntu at prpcompany.com>> wrote:
>>>
>>>     Thanks!
>>>
>>>     The home page is at http://entangle-photo.org/
>>>
>>>     Since Entangle is not in the official repos, I installed it from
>>>     GetDeb: http://www.getdeb.net/software/Entangle
>>>
>>>     On 11/1/2012 7:43 PM, Phill Whiteside wrote:
>>>>     I'd expect USB flash drives to be auto mounted (The screams of "I
>>>>     plugged my flash drive in & it didn't mount - do not worth
>>>>     thinking about :) )
>>>>
>>>>     I'm in no way any expert on this, but IIRC, when I plugged my USB
>>>>     webcam in a few cycles ago, it launched Cheese and not PCManFM.
>>>>     Things will have changed and my laptop as of them is no longer,
>>>>     this one has a built in one. If you have a link to Entangle I'd be
>>>>     happy to install it & see how it gets on.
>>>>
>>>>     Regards,
>>>>
>>>>     Phill.
>>>>
>>>>     On 1 November 2012 23:06, John Hupp <lubuntu at prpcompany.com
>>>> <mailto:lubuntu at prpcompany.com>> wrote:
>>>>
>>>>         Perhaps it is too eager, I don't know.  It seems like standard
>>>>         behavior with removable storage -- it does the same thing with
>>>>         USB flash drives, which is also what Windows does.
>>>>
>>>>         It would also be interesting to figure out why Entangle locks
>>>>         up when it tries to unmount the camera.
>>>>
>>>>         But in the meantime I'm very eager for a work-around.  I've
>>>>         put in a lot of research and testing time on this over the
>>>>         lastfew weeks, and it seems that I'm close to a decent
>>>>         solution with Entangle.  (I like it very much when things work
>>>>         the way they should, and I prefer to see the "right" solution,
>>>>         but I'll admit to some battle-weariness with confronting one
>>>>         issue after another.)
>>>>
>>>>         On 11/1/2012 6:42 PM, Phill Whiteside wrote:
>>>>>         Hi John,
>>>>>
>>>>>         from what you describe I think PCManFM is being maybe just a
>>>>>         little too eager to mount anything that arrives in a USB
>>>>>         port. As such, I'd suggest raising a bug against PCManFM in
>>>>>         the first instance, it can always get re-allocated once the
>>>>>         dev-team have had chance to look into it.
>>>>>
>>>>>         Regards,
>>>>>
>>>>>         Phill.
>>>>>
>>>>>         On 1 November 2012 22:36, John Hupp <lubuntu at prpcompany.com
>>>>> <mailto:lubuntu at prpcompany.com>> wrote:
>>>>>
>>>>>             I'm trying to get a Canon Powershot G1 USB-connected
>>>>>             camera working with remote capture (tethering) using
>>>>>             either Entangle or Gtkam.
>>>>>
>>>>>             Both apps get tripped up on the fact that Lubuntu
>>>>>             auto-mounted the camera. Gtkam simply generates an error
>>>>>             message about the camera already being in use. Entangle
>>>>>             notes the same condition and offers to unmount the
>>>>>             camera, but approving that causes the program to lock up.
>>>>>
>>>>>             Either program launches OK if I manually unmount the
>>>>>             camera from pcmanfm first.
>>>>>
>>>>>             So I'd like to launch the camera program from a script
>>>>>             that first unmounts the camera.
>>>>>
>>>>>             Post #2 in
>>>>> http://ubuntuforums.org/showthread.php?t=967104had a
>>>>>             solution in the command "gvfs-mount -s gphoto2," but
>>>>>             gvfs-mount is not installed by default in Lubuntuand is
>>>>>             not available from the default repos.
>>>>>
>>>>>             I also tried "sudo umount /home/<user>/.gvfs," which was
>>>>>             the mount point suggested to me by "sudo mount." That ran
>>>>>             without error, but the camera did not seem to be truly
>>>>>             unmounted, and both cam apps errored as before.
>>>>>
>>>>>             What's my best solution in Lubuntu?
>>>>>
>>>>
>> >
>> I think you need to be looking at writing udev rules for the camera.
>>
>> -- 
>> Steve
>>
>>
>
>
>

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