cvs commit: src/sys/dev/fxp if_fxp.c if_fxpvar.h

[Maxime Henrion]

Scott Long wrote:
> Maxime Henrion wrote:
> >mux         2004/06/02 15:52:18 PDT
> >
> >  FreeBSD src repository
> >
> >  Modified files:
> >    sys/dev/fxp          if_fxp.c if_fxpvar.h 
> >  Log:
> >  Use the device sysctl tree instead of rolling our own.  Some of the
> >  sysctls were global (hw.fxp_rnr and hw.fxp_noflow), all of them are
> >  now per-device.  Sample output of "sysctl dev.fxp0" with this patch,
> >  with the standard %foo nodes removed :
> >  
> >  dev.fxp0.int_delay: 1000
> >  dev.fxp0.bundle_max: 6
> >  dev.fxp0.rnr: 0
> >  dev.fxp0.noflow: 0
> >  
> >  Revision  Changes    Path
> >  1.213     +18 -24    src/sys/dev/fxp/if_fxp.c
> >  1.31      +2 -2      src/sys/dev/fxp/if_fxpvar.h
> 
> Not having the ability to deal with global settings is a bit
> of a pain.  I had envisioned that something like this would
> be:
> 
> dev.fxp.N.instance_variable
> 
> dev.fxp.global_variable

It doesn't matter for the rnr sysctl, which is just a counter of RNR
events.  It used to be read/write though, but that was bogus because
it's never read in the code, and only incremented, so I changed it to
be read-only.

The noflow sysctl is actually a tunable so most of the time people
using it are already forced to use it per-device since AFAIK, tunables
are only per-devices.  It's however a read/write sysctl because since
it's read in fxp_init(), it could be useful to set it to 1 and just
run "ifconfig fxp0 down; ifconfig fxp0 up" so that it's used.  But
once you know you need this, you'll want to set it as a tunable
anyway.

Now I think you're raising a problem that we're likely to have in a
near future when more drivers are converted to use the device sysctl
tree, and when those drivers have settings that are likely to be
useful globally.  I already pondered having devinfo(8) renamed to
devctl(8) and handle settings we want to do on devices via the
sysctl device tree.  Taking the detour through a userland program
would allow us to have more elaborated features, like setting
something on all devices at once.

Anyways, I didn't think about this long enough to be really sure it's
a good idea, and I don't have the time to handle such a task right
now.  I thought that could be of some interest to others. :-)

> Anyways, this work still looks very nice =-)

Thanks :-)
Maxime