Packet loss on bcm4331

Rafał Miłecki zajec5 at
Tue Aug 14 16:05:42 EDT 2012

2012/8/14 Larry Finger <Larry.Finger at>:
> On 08/14/2012 02:07 PM, George Wright wrote:
>> I have a MacBook with a bcm4331 chip which mostly works in Linux (Fedora
>> 17 w/kernel 3.5.1), but I'm noticing horrible packet loss and throughput
>> a lot of the time.
>> The setup is basically a small apartment with an 802.11bgn router
>> sitting in the living room; I've had the laptop sit directly on top of
>> the router and run ping to another computer wired directly into the
>> access point and experienced 75% packet loss. File transfers are
>> experiencing throughput in the region of 200kB/s to 800kB/s. Oddly
>> enough, the amount of packet loss is significantly reduced if I'm
>> connected in my bedroom (~20 feet from the router and with a couple of
>> walls in between). I've also experienced the same problems with my
>> backup wireless router (a WRT54GL running dd-wrt).
> In b43, power management of 802.11n devices has never been implemented in
> the fullest form. Thus, it is likely that the gain setting is too high when
> you are close to the AP and the resulting distortion is causing failures.

I promise to work on this, but I can provide only N-PHY support (we
have specs for them). I'll try my best to do some power management for
N-PHY for 3.7 merge window.
Right now I'm focused on SoC support for my BCM4706 SoC. But
fortunately I'm getting everything pushed upstream slowly.

Unfortunately BCM4331 is HT-PHY which I can't really improve. We don't
have any specs about that PHY type and support is mostly pure luck.

I may try to improve is a little since I get BCM4706 support (my SoC
has two BCM4331 connected via PCIE), but don't expect much :(


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