I installed Ubuntu 16.04 on my Windows laptop a while ago and i noticed that the wifi connection worked worse than before: now 5ghz wifi networks don't show up on the network manager interface even if 2.4ghz networks are detected and work fine. The laptop is an ASUS model A555L
The output of iwlist wlp3s0 channel is:
wlp3s0 32 channels in total; available frequencies : Channel 01 : 2.412 GHz Channel 02 : 2.417 GHz Channel 03 : 2.422 GHz Channel 04 : 2.427 GHz Channel 05 : 2.432 GHz Channel 06 : 2.437 GHz Channel 07 : 2.442 GHz Channel 08 : 2.447 GHz Channel 09 : 2.452 GHz Channel 10 : 2.457 GHz Channel 11 : 2.462 GHz Channel 12 : 2.467 GHz Channel 13 : 2.472 GHz Channel 14 : 2.484 GHz Channel 36 : 5.18 GHz Channel 38 : 5.19 GHz Channel 40 : 5.2 GHz Channel 42 : 5.21 GHz Channel 44 : 5.22 GHz Channel 46 : 5.23 GHz Channel 48 : 5.24 GHz Channel 52 : 5.26 GHz Channel 56 : 5.28 GHz Channel 60 : 5.3 GHz Channel 64 : 5.32 GHz Channel 100 : 5.5 GHz Channel 104 : 5.52 GHz Channel 108 : 5.54 GHz Channel 112 : 5.56 GHz Channel 116 : 5.58 GHz Channel 120 : 5.6 GHz Channel 124 : 5.62 GHz Current Frequency:2.462 GHz (Channel 11) So in theory i should be able to detect and use 5ghz wifi networks.
Running dmesg turned out some errors which look to be relevant to this question:
ERROR @wl_cfg80211_scan : WLC_SCAN error (-22) ERROR @wl_dev_intvar_get : error (-1) ERROR @wl_cfg80211_get_tx_power : error (-1) I tried to reinstall the bcmwl-kernel-source driver and other things i found googling but nothing i've found works.
iw list output is:
Wiphy phy0 max # scan SSIDs: 1 max scan IEs length: 0 bytes Retry short limit: 7 Retry long limit: 4 Coverage class: 0 (up to 0m) Supported Ciphers: * WEP40 (00-0f-ac:1) * WEP104 (00-0f-ac:5) * TKIP (00-0f-ac:2) * CCMP (00-0f-ac:4) * CMAC (00-0f-ac:6) Available Antennas: TX 0 RX 0 Supported interface modes: * IBSS * managed Band 1: Bitrates (non-HT): * 1.0 Mbps * 2.0 Mbps (short preamble supported) * 5.5 Mbps (short preamble supported) * 11.0 Mbps (short preamble supported) * 6.0 Mbps * 9.0 Mbps * 12.0 Mbps * 18.0 Mbps * 24.0 Mbps * 36.0 Mbps * 48.0 Mbps * 54.0 Mbps Frequencies: * 2412 MHz [1] (20.0 dBm) * 2417 MHz [2] (20.0 dBm) * 2422 MHz [3] (20.0 dBm) * 2427 MHz [4] (20.0 dBm) * 2432 MHz [5] (20.0 dBm) * 2437 MHz [6] (20.0 dBm) * 2442 MHz [7] (20.0 dBm) * 2447 MHz [8] (20.0 dBm) * 2452 MHz [9] (20.0 dBm) * 2457 MHz [10] (20.0 dBm) * 2462 MHz [11] (20.0 dBm) * 2467 MHz [12] (20.0 dBm) (no IR) * 2472 MHz [13] (20.0 dBm) (no IR) * 2484 MHz [14] (20.0 dBm) (no IR) Band 2: Bitrates (non-HT): * 6.0 Mbps * 9.0 Mbps * 12.0 Mbps * 18.0 Mbps * 24.0 Mbps * 36.0 Mbps * 48.0 Mbps * 54.0 Mbps Frequencies: * 5170 MHz [34] (disabled) * 5180 MHz [36] (20.0 dBm) (no IR) * 5190 MHz [38] (20.0 dBm) (no IR) * 5200 MHz [40] (20.0 dBm) (no IR) * 5210 MHz [42] (20.0 dBm) (no IR) * 5220 MHz [44] (20.0 dBm) (no IR) * 5230 MHz [46] (20.0 dBm) (no IR) * 5240 MHz [48] (20.0 dBm) (no IR) * 5260 MHz [52] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5280 MHz [56] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5300 MHz [60] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5320 MHz [64] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5500 MHz [100] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5520 MHz [104] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5540 MHz [108] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5560 MHz [112] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5580 MHz [116] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5600 MHz [120] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5620 MHz [124] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5640 MHz [128] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5660 MHz [132] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5680 MHz [136] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5700 MHz [140] (20.0 dBm) (no IR, radar detection) DFS state: usable (for 275 sec) DFS CAC time: 60000 ms * 5745 MHz [149] (20.0 dBm) (no IR) * 5765 MHz [153] (20.0 dBm) (no IR) * 5785 MHz [157] (20.0 dBm) (no IR) * 5805 MHz [161] (20.0 dBm) (no IR) * 5825 MHz [165] (20.0 dBm) (no IR) * 5920 MHz [184] (disabled) * 5940 MHz [188] (disabled) * 5960 MHz [192] (disabled) * 5980 MHz [196] (disabled) * 6000 MHz [200] (disabled) * 6020 MHz [204] (disabled) * 6040 MHz [208] (disabled) * 6060 MHz [212] (disabled) * 6080 MHz [216] (disabled) Supported commands: * set_interface * new_key * join_ibss * set_pmksa * del_pmksa * flush_pmksa * connect * disconnect software interface modes (can always be added): interface combinations are not supported Device supports scan flush. 
