On 2015-11-23 15:58, Johannes Berg wrote: > On Mon, 2015-11-23 at 15:52 +0100, Michal Marek wrote: >> >> So one issue with this logic is that it is not safe to build and use an >> out-of-tree mac80211 driver after the kernel has been built. Also, any >> new driver needs the 'count MAC80211_NUM_DRIVERS' annotation, but there >> is the runtime check to catch omissions. > > Indeed, the runtime check will catch both of these. Will it catch the former case? The driver built out of has not way to select or increment any of the CONFIG_MAC80211_* options. >> Since this is targeting users >> of very specific configs, how about an opt-in scheme à la >> >> - User has to select CONFIG_MAC80211_SINGLE_DRIVER, the help text >> explains the caveats and lists drivers known to work in such mode. >> - mac80211 uses the Kconfig-defined constants + dynamic bits iff >> CONFIG_MAC80211_SINGLE_DRIVER=y, otherwise it behaves as before. >> - Some build- or compile-time check ensuring that we are not building / >> loading multiple drivers with CONFIG_MAC80211_SINGLE_DRIVER=y. > > That'd be possible - but I know of at least one potential use case that > would like to have two similar drivers, with similar flags: some > routers ship with ath9k hardware for the 2.4 GHz band and ath10k > hardware for the 5 GHz band. Doing "single-driver" and avoiding the > counters would not allow those to have any kind of optimisation, and > such low-power platforms are the ones who'd most likely benefit from > it... I see. > I'd actually Cc'ed you out of confusion, thinking you were maintaining > kconfig. I guess I really should've Cc'ed Yann instead. That's fine. It is a very interesting problem :-). Michal -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
