[conspire] Ubuntu/Digital Camera

Rick Moen rick at linuxmafia.com
Tue Dec 6 10:38:11 PST 2005

Hi, John.  I'm just looking over your older post, in the wake of Daniel 
clarifying that you are running [K]Ubuntu.

Quoting John Andrews (jla1200 at netzero.net):

> I have Ubuntu/Kubuntu installed on my computer. For the first 2 months
> the digital camera stuff worked fine. Now it won't give me access to
> use it. 

Whenever someone says "[Foo] used to work, and then it stopped working",
logically, my very first question is "What changed?"  If you can figure
that out, then often the nature of the problem (and sometimes also the
solution) becomes obvious.

Daniel is almost certainly right that, by far, the easiest way to
resolve this problem is for you to bring your computer, and USB cable,
and digital camera, to the next CABAL event -- or, equivalently, to one
of SVLUG's monthly installfest/workship events in Mountain View.
Accordingly, what follows probably won't help much with your actual
problem, but is more a general mini-essay on the art of problem-solving.
(I hope you won't mind.)

It's a lot easier to figure out what's going on when we can see for
ourselves.  Not intending to be in any way critical of you personally,
but a lot of users' problem reports, especially those of desktop users,
start getting frustratingly vague, exactly at the point where we'd want
to dig in in order to help you out.  

You're doing the best you can with the information the desktop
applications are giving you, but there's very little you have on hand to
convey to us, and of necessity you've been applying your
_interpretation_ to what you're seeing, which unfortunately then becomes
a barrier between us helpers and the raw data.  For example, you say
"used the control center" (by which I assume you mean some version or
other of the KDE "Control Panel" application, kcontrol), and say "It
picked up [your camera] fine", but we really have no way of knowing
specifically what you mean when you say that -- and it's difficult with
a graphical application like that to show us.

This is one reason why, for diagnostic purposes, it's better to use
simple command-line tools with known characteristics, as those (1)
are universally available, (2) predictable in their behaviour, (3)
easy to copy-and-paste the command line the user specified to them and
their returned output, and (4) simple in the sense of not relying on
other requirements being met before they will function properly.

(As a further explanation on that "universally available" bit, you might
well be assuming that everyone else on Linux has access to the software 
you've been using.  This is not the case.  Not everyone by a long
stretch likes KDE or keeps it around, and the same for gPhoto2.  But
every modern Linux system has, say, lsusb and ps.)

I hope you won't feel picked on, but the phrase "It won't give me access
to it" doesn't really tell us a darned thing about what specific
software you were attempting to use, what specifically you did with it,
and what it did in response.  My point is not to complain (hardly!),
but rather to point out that we're prevented from helping you by lack of
useful description.  Nobody's blaming you, but it's frustrating to not
be able to assist.

> I,ve used the control center to add my camera via usb which it
> picked up fine .

As you can probably imagine, this sentence has pretty much the same
problem:  It doesn't really specify what you did (and what the software
did, and what software was involved) in detail, and it gives us only
your interpretation of what happened, instead of the raw data that we
would actually need.

> Then when I try to test the camera or upload pictures it says it can't
> find the camera in the tree.  Also the gphoto2 can't read the cameras
> files either.How do I get permissions back or what ever?The usb works
> normal for the printer.

Thank you for mentioning the bit about the printer:  That's really
useful diagnostic information, as it eliminates a large number of
otherwise possible problem causes.  

For starters, you should (1) make sure you are connecting your camera
directly to the computer's USB port, i.e., _not_ via a USB hub (for
diagnostic purposes -- you might be able to reintroduce the hub, if any,
later), and (2) make sure the camera's mode switch is set to USB mass
storage mode rather than PTP image-transfer mode.  Double-check the USB
physical connection at each end; make sure you are using a known-good
USB cable (e.g., the one that you know works with your printer).

By the way, please be careful about overspecifying the problem:
Computer nerds have a tendency to focus on whatever you claim that the
problem is, which can lead to considerable wasted time if you have
misdefined the problem.  For example, you spoke about needing to "get
the permissions back".  It probably won't happen this time, but I can
easily imagine typical Linux nerds working with you to find and fix
problems with Linux file permissions (e.g., on device files), on the
basis of your describing that as being the problem -- even though you
really had no reason to believe that that _is_ the problem, and were 
merely guessing.

So, please be really careful about accidentally misdefining the problem.
Again, this is one of the reasons why we need to start with _raw data_
rather than your interpretations.  I have a metaphorical saying about
this:  "Techies are from Missouri."  That is, their byword is "Show me."
They would want you, instead of just trying to describe what happened
from memory, to attempt to use your camera with Kubuntu again, and this
time take down detailed and accurate notes about exactly what you did
and what various pieces of hardware and software did, in proper
chronological order.  They might want you to post the exact output of
"lsmod" and "lsusb", and other things.  (I personally am not very
familiar with digital cameras, and have never used gPhoto2, and so
cannot be more specific.)

> The Kscd stopped working again. We edited the group file to add me
> to media:/hdd. Now it says I don't have permissions to use it.

1.  We have no way of knowing what you mean by "the group file".  You 
might mean "/etc/group", except that "media:/hdd" would not make sense 
as syntax for a line in that file.

2.  "KsCD" appears, from my googling, to be a KDE-oriented player for
audio CDs.  But we have no way of knowing what you mean by "stopped
working":  That could mean dozens of things.  (Thus, like the word
"crashed", it is not helpful in diagnostic situations.)  Also, you
didn't explain the bit about "again":  What happened last time?  

3.  You say "It says", but we have no idea what "it" is in this context.

I hope the above is of _general_ use to you, in communicating with the 
technical community.  However, as to the specific technical problems
you're encountering, again, you'll probably find it less frustrating to
just bring everything to a suitable in-person event, rather than further
pursue diagnosis remotely via e-mail.

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