On Thu, Apr 21, 2016 at 11:34:10AM -0500, Seth Forshee wrote: > On Thu, Apr 21, 2016 at 07:12:53PM +0300, Petko Bordjukov wrote: > > On Thu, 21 Apr 2016 17:07:21 +0300, > > Seth Forshee wrote: > > > This is almost certainly because these frequencies require transmit > > > power control. We drop the TX power limits by half (i.e. 3 dB) when TPC > > > is required on account of not supporting TPC. > > > > I was under the impression that the underlying kernel infrastructure had support > > for TPC. What I am observing is that hostapd automatically includes the Power > > Constraint IE in beacons sent out on any channel with DFS enabled. The default > > transmit power reduction is 3dBm. > > > > This means that the TX power of any clients would be limited to 3dBm below the > > TX power of the AP even though it's not required. > > > > Would there be any merit in providing additional information regarding the TX > > power and the target average TX power reduction for the system when TPC is > > supported? > > I'm frankly not certain about the status of kernel support, but my > impression was that some drivers might have some level of TPC support > but that it's not universal. I really haven't been keeping track of it > though. When I looked at adding support for Linux, IIRC the status of affairs was that it was complex, and iffy, and no one ever really implemented it even on Windows / OSX so the adjustments were easier to make so that's what people did. Luis
