The CTL edge is a regulatory concept where you have 'edges' to a regulatory domain that imposes further restrictions. For example, say you have 5500 -> 5600 as a certain set of rules (max txpower 10), and 5400 - 5500 as a certain set of rules (max tx power 20). The spectral mask for 802.11 rates has a certain dB dropoff at the edge. That bleeds to the adjacent channels. Now, you can configure a channel at 5490 to have a TX power of 20, _BUT_ the spectral mask means that there'll be some non-zero amount of RF energy "bled" out over the adjacent channels, which includes the 5500-5600MHz range. Because of this, you need some extra rule that defines what the TX power should be at that particular boundary. Now, for this particular scenario you could infer it from the lower TX power at 5500-5600, but there are still requirements for meeting maximum power output at band edges where the adjacent band is some licenced spectrum or something that we don't run 802.11 on. So we don't have a normal TX power rule for that channel; instead we need to use a CTL rule that says "at this frequency edge, do X." For further information, have a read of how the ctl edge stuff works in the driver and be prepared to consume some nice wine whilst doing so, in order to prevent clawing at your eyeballs at the hoops that you jump through. Adrian -- 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
