Re: [PATCH] Revert "ipw2200: select CFG80211_WEXT"

[Paul Bolle]

On Mon, 2015-01-05 at 11:14 +0100, Arend van Spriel wrote:
> On 01/03/15 23:28, Paul Bolle wrote:
> > Side note: am I correct in thinking that there's some successor to
> > CFG80211_WEXT and that the ipw2200 driver could, at least in theory, be
> > ported to that successor? (ipw2200 hardware appears to be a bit old, so
> > probably no one would care enough to actually do that.)
> > net/wireless/kconfig doesn't mention anything like that, so probably I'm
> > just confused.
> 
> ipw2200 is a WEXT driver using some wext functionality (and struct 
> wiphy) provided by cfg80211 hence it needs CFG80211_WEXT. I guess that 
> is what makes it confusing.

It doesn't help that I hardly know anything about mac80211, cfg80211 and
nl80211 (and lib80211 for that matter). To me these are mostly just
names that end in 80211.

Anyhow, concerning, CFG80211_WEXT: it seems the only functionality
provided by that symbol that ipw2200 uses directly is
cfg80211_wext_giwname(). Perhaps ipw2200 could have a private version of
that function, something like ipw2100's ipw2100_wx_get_name(). Should be
trivial to implement (ie, it could take _me_ a day or two).

But perhaps ipw2200 uses CFG80211_WEXT _indirectly_ too. Ie, in
net/wireless/core.c I stumbled on
    #ifdef CONFIG_CFG80211_WEXT
            rdev->wiphy.wext = &cfg80211_wext_handler;
    #endif


But I net/wireless/wext-core.c I then found
    #ifdef CONFIG_CFG80211_WEXT
            if (dev->ieee80211_ptr && dev->ieee80211_ptr->wiphy)
                    handlers = dev->ieee80211_ptr->wiphy->wext;
    #endif
    #ifdef CONFIG_WIRELESS_EXT
            if (dev->wireless_handlers)
                    handlers = dev->wireless_handlers;
    #endif

(There's much more to discover about WEXT, of course.) Anyhow, IPW2200
uses both CFG80211_WEXT and WIRELESS_EXT and cfg80211_wext_handler and
ipw2200's wireless_handlers appear to cover the same set of IOCTLS (one
exception: SIOCSIWPMKSA). So by now I'm really puzzled how this all fits
together.

Thanks,


Paul Bolle

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