I'm working on my code base and I was surprised by the fact, that the type of the received signal strength for frames received via Netlink is u32, but the actual struct ieee80211_rx_status.signal uses an s8 for signal. I actually refer to this line: https://elixir.bootlin.com/linux/v4.20-rc4/source/drivers/net/wireless/mac80211_hwsim.c#L3250 As we use the signal measurement in dBm (see https://elixir.bootlin.com/linux/v4.20-rc4/source/drivers/net/wireless/mac80211_hwsim.c#L2764), negative dBm values are totally reasonable as received signal strength. Moreover, I don't really know, whether mac80211 or respectively minstrel can do reasonable work with positive values. Was this done intentionally ? On the other hand this line https://elixir.bootlin.com/linux/v4.20-rc4/source/drivers/net/wireless/mac80211_hwsim.c#L1276 inconsistently uses a negative value in the case of not using netlink/wmediumd, which is a decent value. I think it is not possible to easily switch to another type (e.g. s32 or even s8) for the netlink attribute without breaking things, but somebody might correct me. We could do the hack and always negate the value of signal, since positive signal strength values in dBm are practically impossible over the air. Or I could simply use the corresponding u32 value, which will map silently to the "right" negative s8 value, but it doesn't feel right :-) Any suggestions? kind regards Benjamin Beichler -- M.Sc. Benjamin Beichler Universität Rostock, Fakultät für Informatik und Elektrotechnik Institut für Angewandte Mikroelektronik und Datentechnik University of Rostock, Department of CS and EE Institute of Applied Microelectronics and CE Richard-Wagner-Straße 31 18119 Rostock Deutschland/Germany phone: +49 (0) 381 498 - 7278 email: Benjamin.Beichler@xxxxxxxxxxxxxx www: http://www.imd.uni-rostock.de/
