[pvrusb2] PVRUSB2: Unknown Symbols

Mike Isely isely at isely.net
Fri Sep 30 22:27:20 CDT 2005


(see interspersed comments below)

On Fri, 30 Sep 2005, H. \Miz\ Jones wrote:

> Hello list,
> pvrusb2-mci-20050921 builds fine.
> Linux LX.localdomain 2.6.12-1.1456_FC4 #1 Thu Sep 22 02:11:36 EDT 2005
> x86_64 x86_64 x86_64 GNU/Linux
> (Red Hat) Fedora Core 4
> Installs to /lib/modules/`uname -r/pvrusb2
> ... is this intentional?  modprobe doesn't find it there.

Did you run depmod -a first?  (This is a standard thing you do when you
add / remove / change any modules, pvrusb2 or otherwise.  This step is
documented in pvrusb2.html.)

There is no hard requirement for where the modules need to be copied (once
you're inside the module tree for the kernel version you have) so if
there's a better place you would like to put them, then fine.  I just
chose that default because it minimized any chance of colliding with any
module files already there and made it obvious where the driver's files
area so that they can be manually identified and removed if so desired.

> That also requires manually loading both v4l1-compat.ko and
> v4l2-common.ko (ie, modprobe v4l1-compat; modprobe v4l2-common) before
> manually insmodding everything there, which isn't immediately obvious.

This is a symptom of the above problem, so let's focus on that.

> Perhaps a quick note in the documentation or FAQ?

Please read the complete setup instructions which you can find in
http://www.isely.net/pvrusb2.html or as doc/pvrusb2.html in the driver
snapshot.  The stuff in doc/ is exactly the same as what is on the web (at
the time that the snapshot was made).

> The README in the tarball also doesn't explicitly state that the
> firmware is absolutely required, it simply nonchalantly tells you there
> are things in there that might help.

Sounds like the README has to more strongly point you at the contents of
the doc subdirectory.  But...

Every issuse above is (IMHO) addressed in the html documentation.  Please
look especially at doc/pvrusb2.html there or at
http://www.isely.net/pvrusb2.html which is the same thing.  There is a
careful series of steps listed, including admonitions about extracting and
loading the firmware.

Before I started putting things up on the web site last May, the README
had a lot more content, but I had to make a choice.  It was clear that the
web page needed a lot of information about how to use the driver, and I
didn't want to end up maintaining two different copies of the same
information.  I briefly looked at tools that might make it easy to
maintain one common source and to generate HTML and flat ASCII from that
but I quickly ruled that out for two reasons: (1) I didn't find a tool
that really fit well (some came close), and (2) I wanted to distribute
everything in the snapshot tarball, in such a way so that anybody could
recreate the driver and its documentation if needed - and that meant
entangling the driver's documentation with whatever obscure tool I might
have chosen.  I felt it more important to cleanly document everything
about the driver in one place and forgo any kind of document processing
tool, and since more people were likely to see the web pages than the flat
text, I opted to prioritize to the web pages.  So I have been expanding
and organizing the html files ever since and I stripped out of the README
anything that was repeated there or otherwise ran the risk of being
accidentally obsoleted and thereby become misleading.

The takeaway from all this is that I probably need to review the README
and put a strong emphasis there about the need to read the html
documentation, which should already have what you need and probably would
have kept you from being led astray.  Sorry about what happened here, but
you really do need to look more closely at pvrusb2.html.

> Please forgive me if I sound crass, I'm simply reporting a couple minor
> gotchas, having not followed the driver for quite awhile.

I understand.  In the end it doesn't matter whose fault this would be.
It sounds like I could have headed this off by putting a strong pointer in
the README file for the reader to carefully review the main html file...


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