From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Smith Date: Thu, 03 Nov 2011 15:28:12 -0400 Subject: [ath9k-devel] Unrealistic RSSI values being reported Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org I recently upgraded to compat-wireless-3.1-rc8 from compat-wireless-2.6.39-1-sn and have discovered an interesting behavior. When in monitor mode I use the signal strength field reported in radiotap and with 3.1 I am now getting a range of values. The more interesting ones are all the frames reporting a signal of 110+ dBm. To see what is being pulled from the descriptors I dumped rs->rs_rssi to klog when the value was larger than 95. Below is a snippet showing the ranging values, Nov 3 15:00:03 dpsmith-dev-system kernel: [ 5319.907908] [ath9k]: RSSI 107 Nov 3 15:00:03 dpsmith-dev-system kernel: [ 5319.911697] [ath9k]: RSSI -61 Nov 3 15:00:03 dpsmith-dev-system kernel: [ 5319.913553] [ath9k]: RSSI -119 Nov 3 15:00:03 dpsmith-dev-system kernel: [ 5319.913562] [ath9k]: RSSI -59 Nov 3 15:00:03 dpsmith-dev-system kernel: [ 5319.913570] [ath9k]: RSSI -94 Nov 3 15:00:03 dpsmith-dev-system kernel: [ 5319.915880] [ath9k]: RSSI 119 Nov 3 15:00:03 dpsmith-dev-system kernel: [ 5319.915890] [ath9k]: RSSI -109 Nov 3 15:00:03 dpsmith-dev-system kernel: [ 5319.915898] [ath9k]: RSSI 123 Nov 3 15:00:03 dpsmith-dev-system kernel: [ 5319.917743] [ath9k]: RSSI 101 A couple of data points, 1. I have tested two different cards, one having AR9106+AR9160 and one with an AR9382. 2. It appears that it is always the same devices that this occurs for, e.g. pretty confident there are some devices that I collected that I did not see anything out of the 3-10dBm range I know 2.6.39 -> 3.1 is a bit of a jump, but I wanted to push this to the community to see if there are some thoughts or opinions while I dig deeper. My next step is to see if it occurs in 3.0 which should help give me a narrow set of patches to review/bisect to see at what point this was introduced. I would suspect it to be an initval issue, but the two chips I have should have different initval sets. Any thoughts or suggestions would be greatly appreciated. dps