On Mon, Jul 06, 2015 at 04:40:56PM +0200, Zefir Kurtisi wrote: > On 07/06/2015 03:27 PM, Seth Forshee wrote: > > On Fri, Jul 03, 2015 at 05:01:20PM +0200, Zefir Kurtisi wrote: > >> On 07/03/2015 04:20 PM, Wei Zhong wrote: > >> [...] > >> From your other post: > >>>> > > >>>> > - (5490 - 5730 @ 160), (24), DFS > >>>> > + (5490 - 5590 @ 80), (24), DFS > >>>> > >>>> I agree. 5590 is more strict than 5600. > >>>> > >>>> > >>>> On a second thought, 5590 implies channel 116 can't have 40MHz. I think > >>>> that is > >>>> still allowed per regulation. > >>>> > >>>> > >> > >> No, channel 116 is not usable for HT40 if weather radar channels are > >> disabled, > >> since it can only be combined with channel 120 and that one partially > >> falls into > >> the restricted range. > > > > It's not necessary to restrict the band down to 5590 or break out the > > rule for channel 116 separately, the software is smart enough to work > > out what's allowed based on the original rule Wei supplied for 5490-5600 > > MHz. In fact that rule exactly matches what we used to have in db.txt > > for the US prior to the TDWR restrictions being lifted. > > > > Yes, the SW is smart and sane enough to extract the limitations even if they > are > defined less restrictive than required. Which raises the general question of > what > needs to be defined as rule and what can be relied on to be handled correctly > by > the SW. > > Example: why do we need to bother about the max-bw parameter for a rule at > all? We > know there is no 160MHz channel within 5490 and 5600, as does the SW. If we > wrote > (5490 - 5600 @ 160) instead of (5490 - 5600 @ 80), nothing would change. > > To me it sounds not fully consistent to explicitly limit max-bw while relying > on > SW to sanitize frequency ranges. Not that it really matters in practice, but > it > has a potential to simplify the rules (i.e. provide max-bw parameter only if > the > according country defines restrictions and leave SW to handle it otherwise).
The database is just about capturing the rules of the various regulatory bodies. I don't know off the top of my head if there are any cases today where the maximum allowed badwidth in a given range is less than the maximum possible bandwidth in that range, but it certainly doesn't seem impossible. So I wouldn't call it inconsistent. We aren't expecting the kernel to "sanitize" the frequency ranges either. It doesn't rely on the regdb to tell it which frequencies are legitimate. Seth -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
