RaspbPi HOWTO

[Dan Poirot]

The TI BeagleBoard had a similar issue plaguing early revisions. I seem to recall a hardware spin on one component resolved the problem.

 

I have used both the BeagleBoard C3 and RaspPi B with Data Distribution System (real-time, UDP pub/sub messaging) when I worked at RTI.

 

I never saw any indication of the 'USB hanging' on either device. 

 

I was running messages on the IP stack as fast as the CPU could process them. ...but then again, I was also using lab-grade power.

 

 

...recall, the class of boards being discussed are basically minimal reference designs for cell phone chips...

 

-    dan

 

 

From: devel [mailto:devel-bounces at ntpsec.org] On Behalf Of Frank Nicholas
Sent: Tuesday, May 03, 2016 6:35 PM
To: Hal Murray <hmurray at megapathdsl.net>
Cc: gpsd-dev at nongnu.org; devel at ntpsec.org
Subject: Re: RaspbPi HOWTO

 

 

On May 3, 2016, at 6:50 PM, Hal Murray <hmurray at megapathdsl.net <mailto:hmurray at megapathdsl.net> > wrote:

 

The problem with the Pi was USB related.  I don't see troubles when using the 
Ethernet, but WiFi hangs occasionally (days).  All the USB WiFi gizmos from 
Adafruit use the same chip.  My guess is that the WiFi chip does something 
strange and the hardware/firmware doesn't handle that case.

I've got a couple of units that use a different chip on order.  That might 
tell me something.

 

I have 15 Raspberry Pi’s.  I’ve used the original B thru Pi 3, and the “zero".  I’ve had no issues with USB.  I use Gentoo on all my Pi’s.  I use USB for bluetooth, WiFi & as the root partition (USB storage).  I’ve used at least 5 x brands of USB WiFi adapters.  I’ve pretty much standardized on “Edimax Technology Co., Ltd EW-7811Un 802.11n Wireless Adapter [Realtek RTL8188CUS]” as of late, but I’ve used other chip sets (from Amazon for < $10).  I’ve never had any WiFi issues or USB issues.

 

With regards to WiFi, if I ping a Pi, sometimes 1-3 pings fail, before the WiFi seems to "wake up".  I’ve not been able to track this down to a chipset or USB specific (it happens on the Pi 3, with built-in Broadcom WiFi).  All my scripts that automate things with my Pi’s that are on WiFi, start with a “ping -c 4 -q $host”.  ALWAYS by the 4th ping, the Pi is responding.  With the Ethernet, always by the 2nd ping, the Pi is responding.

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