Luis R. Rodriguez wrote:
On Sat, Sep 19, 2009 at 8:46 PM, Tim Gardner <tim.gardner@xxxxxxxxxxxxx> wrote:
Luis R. Rodriguez wrote:
Today at the summit we spoke about mangling symbols for driver-slect.
Here's a quick nasty take on this but without doing this for driver-select
specifically just for testing. It seems to compile, but someone more
motivated
may want to test and make this apply somehow only for driver-select or
perhaps
when a -D define is used.
Reason for this is to help distributions / OEMs / ODMs who want to replace
just *one* driver with compat-wireless.
I think it would be better to generate the list of mangled symbols
dynamically.
Agreed, that is the part I left out, as a TODO to someone interested.
I'm working on a patch (it works with 2.6.31), but I need to test with
older kernels.
In older Ubuntu releases (before depmod behavior was
corrected), we have to run a 'munge' script to preface all of the exported
symbols so that a compat-wireless driver references the compat-wireless
protocol stack symbols. See the attached munge script for compat-wireless on
2.6.24.
Please correct me if I'm wrong but I believe the script seems to do
what I did just that it actually edited the files with the changes, I
prefer the way I did this as it requires less work to maintain and
understand IMHO.
I'm fine with that, in fact its a bit faster since my munge script is a
bit slow. It'll also make dealing with kernel version dependent symbol
munge exceptions a bit simpler.
One thing that is worth mentioning is that the module names need to be
changed for older user space environments, otherwise depmod mucks things
up in interesting ways.
We can either do something like this for compat-wireless, or we
could use a subset of this logic to generate the list of symbols contained
within the '#ifdef CONFIG_COMPAT_WIRELESS_MANGLE' clause.
So I was under the impression you would use this only if you are using
./scripts/driver-select to select one driver out of the whole tree,
but it seems you actually use this for all the drivers on
compat-wireless for the Ubuntu linux-backports-modules package. I take
it you put lbm stuff then into some /lib/modules/$(uname)/compat/ and
use a sort of /etc/depmod.d/01-compat.conf to prefer compat over
updates/ or kernel/ ?
For LBM I've taken a scorched earth approach, i.e., _all_ drivers in
compat-wireless get built. The vast bulk of users that I deal with are
only interested in one driver, but I don't know a priori _which_ driver.
The use case where they would want to use a mainline driver at the same
time as a different compat-wireless driver is fairly rare (which my
approach makes impossible).
rtg
--
Tim Gardner tim.gardner@xxxxxxxxxxxxx
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