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I have been trying to set up a hotspot using my EDUP 802.11n USB adapter on Archlinux. As I understand, this USB adapter is supposed to support AD-HOC. However, I am unable to set hot spot up, and I can also confirm that ad-hoc is not supported with this device.

However I suspect that I might be missing something still. It is surprising that this USB adapter does not support ad-hoc mode. Could you guide me through if I am missing anything?

iw list output:

Wiphy phy1
wiphy index: 1
max # scan SSIDs: 4
max scan IEs length: 2257 bytes
max # sched scan SSIDs: 0
max # match sets: 0
Retry short limit: 7
Retry long limit: 4
Coverage class: 0 (up to 0m)
Device supports T-DLS.
Supported Ciphers:
    * WEP40 (00-0f-ac:1)
    * WEP104 (00-0f-ac:5)
    * TKIP (00-0f-ac:2)
    * CCMP-128 (00-0f-ac:4)
    * CCMP-256 (00-0f-ac:10)
    * GCMP-128 (00-0f-ac:8)
    * GCMP-256 (00-0f-ac:9)
    * CMAC (00-0f-ac:6)
    * CMAC-256 (00-0f-ac:13)
    * GMAC-128 (00-0f-ac:11)
    * GMAC-256 (00-0f-ac:12)
Available Antennas: TX 0 RX 0
Supported interface modes:
     * managed
     * monitor
Band 1:
    Capabilities: 0x17e
        HT20/HT40
        SM Power Save disabled
        RX Greenfield
        RX HT20 SGI
        RX HT40 SGI
        RX STBC 1-stream
        Max AMSDU length: 3839 bytes
        No DSSS/CCK HT40
    Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
    Minimum RX AMPDU time spacing: 2 usec (0x04)
    HT TX/RX MCS rate indexes supported: 0-7, 32
    Bitrates (non-HT):
        * 1.0 Mbps (short preamble supported)
        * 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)
Supported commands:
     * new_interface
     * set_interface
     * new_key
     * start_ap
     * new_station
     * new_mpath
     * set_mesh_config
     * set_bss
     * authenticate
     * associate
     * deauthenticate
     * disassociate
     * join_ibss
     * join_mesh
     * remain_on_channel
     * set_tx_bitrate_mask
     * frame
     * frame_wait_cancel
     * set_wiphy_netns
     * set_channel
     * tdls_mgmt
     * tdls_oper
     * probe_client
     * set_noack_map
     * register_beacons
     * start_p2p_device
     * set_mcast_rate
     * connect
     * disconnect
     * set_qos_map
     * set_multicast_to_unicast
software interface modes (can always be added):
     * monitor
interface combinations are not supported
HT Capability overrides:
     * MCS: ff ff ff ff ff ff ff ff ff ff
     * maximum A-MSDU length
     * supported channel width
     * short GI for 40 MHz
     * max A-MPDU length exponent
     * min MPDU start spacing
Device supports TX status socket option.
Device supports HT-IBSS.
Device supports SAE with AUTHENTICATE command
Device supports low priority scan.
Device supports scan flush.
Device supports AP scan.
Device supports per-vif TX power setting
Driver supports full state transitions for AP/GO clients
Driver supports a userspace MPM
Device supports active monitor (which will ACK incoming frames)
Device supports configuring vdev MAC-addr on create.
max # scan plans: 1
max scan plan interval: -1
max scan plan iterations: 0
Supported TX frame types:
     * IBSS: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
     * managed: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
     * AP: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
     * AP/VLAN: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
     * mesh point: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
     * P2P-client: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
     * P2P-GO: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
     * P2P-device: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
Supported RX frame types:
     * IBSS: 0x40 0xb0 0xc0 0xd0
     * managed: 0x40 0xb0 0xd0
     * AP: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
     * AP/VLAN: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
     * mesh point: 0xb0 0xc0 0xd0
     * P2P-client: 0x40 0xd0
     * P2P-GO: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
     * P2P-device: 0x40 0xd0
Supported extended features:
    * [ RRM ]: RRM
    * [ FILS_STA ]: STA FILS (Fast Initial Link Setup)
    * [ CQM_RSSI_LIST ]: multiple CQM_RSSI_THOLD records
    * [ CONTROL_PORT_OVER_NL80211 ]: control port over nl80211
    * [ SCAN_RANDOM_SN ]: use random sequence numbers in scans
    * [ SCAN_MIN_PREQ_CONTENT ]: use probe request with only rate IEs in scans
    * [ CONTROL_PORT_NO_PREAUTH ]: disable pre-auth over nl80211 control port support
    * [ SCAN_FREQ_KHZ ]: scan on kHz frequency support
    * [ CONTROL_PORT_OVER_NL80211_TX_STATUS ]: tx status for nl80211 control port support

output of nmcli device wifi hotspot ifname wlp0s20u1 ssid toto password toto:

Error: Device 'wlp0s20u1' supports neither AP nor Ad-Hoc mode.

output of sudo iw wlp0s20u1 set type ibss:

command failed: Operation not supported (-95)

output of sudo iwconfig wlp0s20u1 mode ad-hoc

Error for wireless request "Set Mode" (8B06) :
SET failed on device wlp0s20u1 ; Operation not supported.

My question is, can I be absolutely sure that this device does not support ad-hoc mode, and I should buy a usb-adapter that supports it? I am sceptical because I assumed that such a device would of course support such a niche mode.

I still want to believe that if I get some configuration right, it will work. What do you think?

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  • The question is not if the hardware supports hotspot. It is "Does the hardware AND the Linux driver support hotspot for this device". BOTH must do before it can work. It is psosible the open-source Linux driver doesn't, while the proprietary Windows driver from the vendor does support it.
    – Tonny
    Commented Jan 5, 2022 at 14:48
  • Is there a way to investigate this further? In case a linux driver exists for that?
    – hrk
    Commented Jan 5, 2022 at 16:16

1 Answer 1

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iw clearly says:

Supported interface modes:
     * managed
     * monitor

With a good network adapter, the list could look like this:

      Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * AP/VLAN
                 * WDS
                 * monitor
                 * mesh point
                 * P2P-client
                 * P2P-GO

So no, this cannot work. And no, there is no “law” saying that all Wi-Fi adapters must support infrastructure mode. I would fully expect cheaper adapters (like this one) to not support it.

If you can, get an internal (Mini PCIe, M.2 or PCIe) adapter with a well-known chipset. Looking at the chipset is the best solution anyway. Unfortunately, with new hardware revisions, it can chance without notice.

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  • I understand, many thanks! I was hoping if a configuration would add "ad-hoc" to the "Supported interface modes:" section, but apparently not. Thanks for your recommendation.
    – hrk
    Commented Jan 5, 2022 at 16:14

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