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Re: differences between installs affecting hardware

Dick Thomas wrote:
> I have a black magic intensity pro capture card and it works
> perfectly.... but if I install gnome3 as my default desktop 1st via
> the network install cdrom then install kde, Xfce, etc. It doesn't
> allow me to power down or eject a cdrom or any other "user actions"
> untill I rmmod blackmacgic (the capture card module) and restart X
> But if I install Xfce 1st using the same netboot cdrom and then
> install the gnome task it works perfectly

How strange!  I can see that having taken a while to figure out.

> What differences would installing Xfce 1st make that installing gnome
> over the top make? (Just so I can report a bug to them)

By default recent Debian now configures apt to install Recommends: by
default.  When a package is installed apt will install any Depends:
and Recommends: for that package.  (Many of us turn off the
installation of Recommends:.)

When an individual dependency is installed it may not be a simple
dependency on "foo".  It may be "foo | bar | other".  If I contrive an
example package "package1: foo | bar" and "package2: bar"
and you install package1 first you will get:


Then if you install package2 you get:


But if you install package2 first then package2 will pull in bar.


Since bar is now installed apt will assume that is what you want.  The
dependency of package1 is satisfied by bar.  So now with package1 it
doesn't need anything else installed.


I hope that explains at least one case where the order of installation
will affect the end result of what you have installed.

To debug this further I would install one way and collect a full list
of installed packages.  Then install the other way and collect a
second full list of packages.  Then compare the two lists.

What that should yield is a difference.  Probably a missing package.
If you then install the way that isn't working and then install the
missing package it should work the same as the other way.  If it is
only due to the missing package.

Another possibility is that the order of installation will leave the
state in the configuration of the last package to be installed.  There
are some "debian-alternatives" that have equal priority.  For
alternatives of equal priority the last one installed takes
precedence.  (If alternatives have different priorities then the
highest priority takes precedence.)


And I am sure there are other potential differences too.


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