Chapter 3. Frequently Asked Questions (FAQ)

Possible answers:

Check http://www.teaser.fr/~hfiguiere/linux/digicam.html for general information about digicam support under Linux, BSD, and others.

Check http://gphoto.org/proj/libgphoto2/support.php for camera support in the latest libgphoto2 release.

libgphoto2 is not meant in any way to use webcams. It only works with still image cameras, and is designed to fetch images out of the internal storage of these cameras. It also eventually can be used to remote control the camera to take pictures, it the camera has support for it and if the driver can do it. But not at all libgphoto2 has been designed to be tool to operate webcams nor do we support these devices. There are other solutions for that. Try searching Google.

The exact error message looks like

	      Could not find USB device (vendor 0x0000, product 0x0000). Make
	      sure this device is connected to the computer
	    

You have to set up the permissions on your USB device correctly. See Section 4.3, “Setting up permissions for USB ports”.

The exact message looks like

	      *** Error ('Could not claim the USB device') ***

	      Could not claim interface 0 (Operation not permitted). Make sure no
	      other program or kernel module (e.g. dc2xx or stv680) is using the 
	      device and you have read/write access to the device. 
	    

You have to make sure that no such kernel module is loaded and that you have set up the permissions on your USB device correctly, such that you have (non-root) write access to the camera device. How to set this up, is described at Section 4.3, “Setting up permissions for USB ports”.

This can also happen with cameras that works as USB Mass Storage devices. A notable example is if you have an Olympus Camera that gets auto- detected as an Olympus C-2040Z. In this case, you can try, if you run Linux, to remove the usb-storage kernel module and attempt to use libgphoto2 with it. But, unless you want to control the camera (not all the model supports it), it is not a recommended solution. Keeps using USB Mass Storage. Some of these Olympus supports to be switched to "PC Control" mode in order to be remote controlled with an external program like one using libgphoto2.

The exact message looks like

		*** Error ***
		An error occurred in the io-library ('Could not lock the device'): Camera is
		already in use.

		*** Error (-60: 'Could not lock the device') ***
	    

This means another process on the system is using the camera already. Cameras supported by libgphoto2 can be accessed by file managers like Nautilus or Dolphin via their virtual file filesystem and their technology opens the cameras as soon as they are plugged in.

One major system in use is the GNOME virtual filesystem gvfs. To detect if this is the case, you can run gvfs-mount -l. If this reports GPhoto device, your camera is likely blocked by it. In that case you can try using gvfs-mount -s gphoto2 to umount the virtual filesystem and replugin the camera. Verify with gvfs-mount -l if it is really unmounted.

On MacOS X the built-in PTP camera tool might block libgphoto2 usage. It is a process called PTPCamera which can be found using the UNIX ps command and killed with the UNIX kill command.

If this does not help, and you still get "Could not claim the device" errors, try this user supplied tool https://github.com/mejedi/mac-gphoto-enabler which does slightly more intrusive changes to MacOS to avoid it grabbing the camera.

First check that your camera is supported.

Then try to run gphoto2 --list-ports and look whether the ports you want to use are listed there:

Then try to run gphoto2 --auto-detect and look whether the camera is detected.

If your gphoto2 cannot access the USB device as non-root users, you have to set up hotplugging correctly. See Section 4.3, “Setting up permissions for USB ports” for details.

AND DO NOT RUN gphoto2 AS ROOT. And no other libgphoto2 frontend either.

Yes, many times. The release number ("2.1.1") and the library version ("2.0.3") are by their respective definitions completely unrelated. As we won't “fix” a problem which is not there, please stop bugging us with that “problem”.

No idea. Sometimes it works and sometimes it doesn't. If you know a solution, please let us know.

You can look into the README file of your driver driver. It is located in camlibs/driver/ in your source tree. If you do not have a source tree, that is bad luck up to and including release 2.1.1 - we will install the README files in a future release, though.

Just press the button on the dock so that the USB device gets detected by the system and that gphoto2 software can detect it.

This is a longstanding bug with the G1 and Pro 90 IS, and a relatively new bug with the G2. With the G2, it was introduced with a new camera firmware (G2 1.0.0.0 worked, 1.1.0.0 does not). We haven't fixed this bug yet since none of the active gphoto2 developers owned one of these cameras until recently (i.e. updated his G2's firmware).

Your options are as follows, in descending order of preference:

There is some more info regarding this at http://krixor.xy.org/fredrik/gp/canon-g1-ac-problem/. Good luck.

There is a bug in the Linux 2.4.18 USB driver which may result in random crashes of the libgphoto2 PTP driver. Please upgrade to a more recent kernel.

Cool down, Joe, and listen to the wise words of Linda MacPhee-Cobb:

[ If you are not getting a response from a camera plugged into the serial port, check your /var/log/boot.msg file for the following entry near the end: ]

		*This package use the ttyS0 device by default.
		The installation of this package only makes sense
		if you use a braille display.
	      

[ This is from blinx, and you will need to turn it off, or better, uninstall it. ]

We provide SVN write access to persons that show continued interest in a specific part of gphoto2. If there is already a person maintaining this specific part of gphoto2 (i.e. a camera driver), we prefer you submit patches to the maintainer who will then check them in or request modifications.

Note that CVS has been discontinued. We are using Subversion (SVN) since 2006-03-14.

If your name is not listed in libgphoto2/MAINTAINERS, and if we haven't heard from you lately, we assume that you finished your work on gphoto2 and that you don't need write access any longer. If this is not the case, please contact one of the project admins.

Note that CVS has been discontinued. We are using Subversion (SVN) since 2006-03-14.

	      alice@host:~$ # If you do not care about preserving EXIF information
	      alice@host:~$ jpegtran -copy all -rotate 90
	      alice@host:~$ 
	      alice@host:~$ # If you want to preserve EXIF information
	      alice@host:~$ jhead -cmd 'jpegtran -rotate 90 -outfile &o &i' my-pic.jpg
	    

You can get the jpegtran from the libjpeg package and jhead from http://www.sentex.net/~mwandel/jhead.

We don't have the money to buy Windows and something like Visual C. Therefore, we can't provide you a gphoto2 for Windows. You have two choices (at least):

You are running your libgphoto2 frontend (gphoto2, gtkam, digikam, etc.) with an old version of libgphoto2, even though you compiled it with a newer libgphoto2! Probably you have an old libgphoto2 in /usr/lib and the newer one in /usr/local/lib.

To solve that problem, go through the following list.

First of all make sure, that you have only one instance of gphoto2 and libgphoto2 installed on your system. Unless you know what you're doing you should remove all gphoto2 installation, then you may do (as root):

	      host:~# rm -rf /usr/local/lib/gphoto2* /usr/local/lib/libgphoto2*
	      host:~# rm -rf /usr/lib/gphoto2* /usr/lib/libgphoto2*
	    

Above applies especially if you use both pre-packaged and CVS/SVN versions.

After that, install the newest version of libgphoto2 and gphoto2 and test whether it works now.

I don't know what stow is, but have a look at https://sourceforge.net/tracker/index.php?func=detail&aid=553647&group_id=8874&atid=108874" Sourceforge bug #553647 .

If you don't have pkg-config installed yet, then please install it.

Otherwise, your PKG_CONFIG_PATH variable doesn't contain the pkgconfig/ directory in the lib/ directory of your libgphoto2 installation.

For a default installation, run

alice@host:~$ PKG_CONFIG_PATH=/usr/lib/pkgconfig:/usr/local/lib/pkgconfig
alice@host:~$ export PKG_CONFIG_PATH
	      

and now run the gphoto2 ./configure again.