From dennis at tealdrones.com  Fri Oct  6 14:47:00 2017
From: dennis at tealdrones.com (Dennis Millard)
Date: Fri, 6 Oct 2017 15:47:00 -0600
Subject: Restricting BCM4354 to 802.11b only
Message-ID: <04e66bc2-8c34-f513-cd75-b8ea6f9f02c5@tealdrones.com>

I'm developing on an nVidia TX1 SOM which has an integrated BCM4354 
chipset.? The SOM is running Ubuntu 16.04 Linux (64-bit ARM)

I have an application where I need long range with low bandwidth 
requirements.? It seems that 802.11b has the best receive sensitivity, 
and I need to reduce latency caused by modulation switching (i.e. 802.11 
b, g, n etc).? I'm looking for a way to configure the BCM43 chipset to 
lock in to 802.11b mode only, so I want to disable 802.11g and 802.11n 
modes.

I'm capable of making kernel driver modifications if necessary, but I 
don't have the required information to do this.? I've seen references on 
google to the Broadcom WLAN client utility, or "wl", but it's not freely 
available anywhere.

Does anyone have any advice on where to turn for information on how to 
do this?? Thanks.

 ?? -Dennis




From adrian at freebsd.org  Fri Oct  6 14:53:18 2017
From: adrian at freebsd.org (Adrian Chadd)
Date: Fri, 6 Oct 2017 14:53:18 -0700
Subject: Restricting BCM4354 to 802.11b only
In-Reply-To: <04e66bc2-8c34-f513-cd75-b8ea6f9f02c5@tealdrones.com>
References: <04e66bc2-8c34-f513-cd75-b8ea6f9f02c5@tealdrones.com>
Message-ID: <CAJ-Vmom2vjs9s1=xPnhR7gGTzTZ=JcNdQks5TBQZjmM1CPseRQ@mail.gmail.com>

On 6 October 2017 at 14:47, Dennis Millard <dennis at tealdrones.com> wrote:
> I'm developing on an nVidia TX1 SOM which has an integrated BCM4354 chipset.
> The SOM is running Ubuntu 16.04 Linux (64-bit ARM)
>
> I have an application where I need long range with low bandwidth
> requirements.  It seems that 802.11b has the best receive sensitivity, and I
> need to reduce latency caused by modulation switching (i.e. 802.11 b, g, n
> etc).  I'm looking for a way to configure the BCM43 chipset to lock in to
> 802.11b mode only, so I want to disable 802.11g and 802.11n modes.
>
> I'm capable of making kernel driver modifications if necessary, but I don't
> have the required information to do this.  I've seen references on google to
> the Broadcom WLAN client utility, or "wl", but it's not freely available
> anywhere.
>
> Does anyone have any advice on where to turn for information on how to do
> this?  Thanks.

Hi,

Have you noticed any actual modulation switching latency? Ideally it's
just enabling a different PHY path and so the latency should be
effectively nil.

Also, BCM4354 is a fullmac SDIO 11ac chip, not a b43 chip. :-)

And the TL;DR is - yes, there'll be an ioctl command to send to the
chip to tell it which PHY mode to operate in, and I bet you can set it
to operate on 'b' only. I just don't know off-hand on the brcmfmac
driver what that is, and you should likely ask on linux-wireless where
the brcmfmac people watch out.



-adrian


From dmitry.f.kozlov at gmail.com  Mon Oct 23 15:43:16 2017
From: dmitry.f.kozlov at gmail.com (Dmitry Kozlov)
Date: Tue, 24 Oct 2017 01:43:16 +0300
Subject: FATAL: Module wl not found in directory
 /lib/modules/4.13.0-16-lowlatency Ubuntu 17.10
Message-ID: <CAGSoEtrBubdcVhSzfn1uagqAdoq2V2YOV1tR2cXTaXH=gNxX2w@mail.gmail.com>

Hello,

I have following problems with my BCM43142 802.11b/g/n wireless
adapter after upgrading to Ubuntu 17.10:

08:00.0 Network controller: Broadcom Limited BCM43142 802.11b/g/n (rev 01)
    Subsystem: Hewlett-Packard Company BCM43142 802.11b/g/n
    Flags: fast devsel, IRQ 255
    Memory at c6100000 (64-bit, non-prefetchable) [size=32K]
    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 00-00-af-ff-ff-e6-74-29
    Capabilities: [16c] Power Budgeting <?>

$ sudo apt install --reinstall bcmwl-kernel-source
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
Need to get 0 B/1 544 kB of archives.
After this operation, 0 B of additional disk space will be used.
(Reading database ... 240009 files and directories currently installed.)
Preparing to unpack
.../bcmwl-kernel-source_6.30.223.271+bdcom-0ubuntu3_amd64.deb ...
Removing all DKMS Modules
Done.
Unpacking bcmwl-kernel-source (6.30.223.271+bdcom-0ubuntu3) over
(6.30.223.271+bdcom-0ubuntu3) ...
Setting up bcmwl-kernel-source (6.30.223.271+bdcom-0ubuntu3) ...
Loading new bcmwl-6.30.223.271+bdcom DKMS files...
Building for 4.13.0-16-lowlatency
Building for architecture x86_64
Module build for kernel 4.13.0-16-lowlatency was skipped since the
kernel headers for this kernel does not seem to be installed.
modprobe: FATAL: Module wl not found in directory
/lib/modules/4.13.0-16-lowlatency
update-initramfs: deferring update (trigger activated)
Processing triggers for shim-signed (1.32+0.9+1474479173.6c180c6-1ubuntu1) ...
Secure Boot not enabled on this system.
Processing triggers for initramfs-tools (0.125ubuntu12) ...
update-initramfs: Generating /boot/initrd.img-4.13.0-16-lowlatency


-- 
Best regards,
Dmitry Kozlov