Cannot increase wifi card power using iwconfig

Question

So I set up a hotspot using hostapd, isc-dhcp-server and MASQUERADING. The hotspot works and I can access Internet.

Problem

The connection speed is too slow.

When I connect to my hotspot (via android 4.1, Snapdragon S3), I see a connection speed of 65mbps, which drops down to 1mbps in seconds.

I know this isn't a hardware issue as I can easily get 24mbps (54mbps link) out of my ethernet connection on Windows (via connectify).

Information

iwconfig:

mon.wlan0  IEEE 802.11bgn  Mode:Monitor  Tx-Power=19 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:on

eth0      no wireless extensions.

lo        no wireless extensions.

wlan0     IEEE 802.11bgn  Mode:Master  Tx-Power=19 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:off

iw list:

Wiphy phy0
    Band 1:
        Capabilities: 0x70
            HT20
            Static SM Power Save
            RX Greenfield
            RX HT20 SGI
            RX HT40 SGI
            No RX STBC
            Max AMSDU length: 3839 bytes
            No DSSS/CCK HT40
        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
        Minimum RX AMPDU time spacing: 8 usec (0x06)
        HT TX/RX MCS rate indexes supported: 0-7
        Frequencies:
            * 2412 MHz [1] (19.0 dBm)
            * 2417 MHz [2] (19.0 dBm)
            * 2422 MHz [3] (19.0 dBm)
            * 2427 MHz [4] (19.0 dBm)
            * 2432 MHz [5] (19.0 dBm)
            * 2437 MHz [6] (19.0 dBm)
            * 2442 MHz [7] (19.0 dBm)
            * 2447 MHz [8] (19.0 dBm)
            * 2452 MHz [9] (19.0 dBm)
            * 2457 MHz [10] (19.0 dBm)
            * 2462 MHz [11] (19.0 dBm)
            * 2467 MHz [12] (19.0 dBm) (passive scanning, no IBSS)
            * 2472 MHz [13] (19.0 dBm) (passive scanning, no IBSS)
            * 2484 MHz [14] (disabled)
        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

lspci -v:

0a:00.0 Network controller: Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter (rev 01)
    Subsystem: Hewlett-Packard Company Device 1795
    Flags: bus master, fast devsel, latency 0, IRQ 19
    Memory at d4500000 (64-bit, non-prefetchable) [size=16K]
    Capabilities: [40] Power Management version 3
    Capabilities: [58] Vendor Specific Information: Len=78 <?>
    Capabilities: [48] MSI: Enable- Count=1/1 Maskable- 64bit+
    Capabilities: [d0] Express Endpoint, MSI 00
    Capabilities: [100] Advanced Error Reporting
    Capabilities: [13c] Virtual Channel
    Capabilities: [160] Device Serial Number <removed>
    Capabilities: [16c] Power Budgeting <?>
    Kernel driver in use: bcma-pci-bridge

0b:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 07)
    Subsystem: Hewlett-Packard Company Device 1818
    Flags: bus master, fast devsel, latency 0, IRQ 43
    I/O ports at 2000 [size=256]
    Memory at d4404000 (64-bit, prefetchable) [size=4K]
    Memory at d4400000 (64-bit, prefetchable) [size=16K]
    Capabilities: [40] Power Management version 3
    Capabilities: [50] MSI: Enable+ Count=1/1 Maskable- 64bit+
    Capabilities: [70] Express Endpoint, MSI 01
    Capabilities: [b0] MSI-X: Enable- Count=4 Masked-
    Capabilities: [d0] Vital Product Data
    Capabilities: [100] Advanced Error Reporting
    Capabilities: [140] Virtual Channel
    Capabilities: [160] Device Serial Number <removed>
    Kernel driver in use: r8169

Ubuntu Release:

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=13.10
DISTRIB_CODENAME=saucy
DISTRIB_DESCRIPTION="Ubuntu 13.10"
Linux pr3d4tOr 3.11.0-17-generic #31-Ubuntu SMP Mon Feb 3 21:52:43 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

What I have tried:

• Transmission power:

  prakhar@pr3d4tOr:~$ sudo iwconfig mon.wlan0 txpower 24

• Bit rate:

  prakhar@pr3d4tOr:~$ sudo iwconfig mon.wlan0 rate auto

• Disable power management:

  prakhar@pr3d4tOr:~$ sudo iwconfig mon.wlan0 power off Error for wireless request "Set Power Management" (8B2C) : SET failed on device mon.wlan0 ; Invalid argument.

I tried the above for wlan0 as well. No results. Can anyone guide as to what might be the problem?

Solution

Ok, so I figured out the problem.

It appears that the current driver is use (bcma-pci-bridge) doesn't fully support my Wireless Card (Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter). If I let my computer go to sleep and wake it up again, the Wi-Fi card stays in low power mode, hence the 1mbps speed.

On boot up, the sppeds are correctly varying from 1mbps to 54mbps.

The other alternative, bcmwl-kernel-source, while giving optimum wireless performance, doesn't support AP mode at all.

I haven't been able to find any other drivers.

Hope this helps somebody.

EDIT: Switching to brcmsmac adds AP mode.

prakhar@aS4v4g3wOrld:~$ iw list

    Supported interface modes:
         * IBSS
         * managed
         * AP
         * AP/VLAN
         * monitor
    software interface modes (can always be added):
         * AP/VLAN
         * monitor

(Partial output).

Head to this article to install.

Comments

[freedev]

I don't know if this comment could help, few years ago I changed my linux laptop for a macbook, and now I'm a bit "rusty". Anyway, in some circumstances, it was possible dynamically unload (rmmod) and load (modprobe) linux drivers. Maybe this could help to reset your driver configuration and avoid to reboot your device.