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Joined: Mon Jul 09, 2012 5:51 pm

smsc problems

Mon Jul 09, 2012 6:23 pm

I have been looking into why I can't get my wireless Microsoft keyboard and mouse to work properly. That is missed keys, sticky keys and fairly broken network connectivity at the same time.

A wired HP keyboard and mouse through a PS/2 adaptor are fine.

People have written loads about power supplies, checking 5v, doing things with USB cables and that the device is unfortunately not compatible. I don't buy it.

"The NCP1117 is a low dropout regulator" only when "low" has the same meaning as in the sentence "bankers generally have low renumeration."

The design doesn't leave a lot of headroom so I have replaced my 3v3 regulator with another device that drops 250mV to be sure. I've also used different power supplies, both a powered and unpowered hub and scoped the 5v and 3v3 rails.

Also with the same wireless receiver dongle plugged into my Marvell Sheevaplug also running a recentish Debian I can dump the appropriate /dev/input device and it's fine in that though I'm not overly familiar with input event data I can see events that correspond to what my paws are doing on the keyboard and I can see what is convincingly the "keyup" event as there is a zero in a particular byte.

My other observation is the vast quantity of kernel output from the smsc driver which, if you didn't have performance problems before, you will now. Many "kevent 4 may have been dropped" per second but I have also one or two others. Thanks to the configuration many log files get this and for some reason not instead the "last messages repeated a squillion times" traditional sysloggers did by default.

Given that the smsc device runs off 3v3 now via my better regulator and that the network breaks at the same time I suspect some or all of

The smsc device
some electrical problem
poor device driver

Any thoughts welcome.

Jon Schneider

Posts: 72
Joined: Sun May 20, 2012 11:26 pm

Re: smsc problems

Mon Jul 09, 2012 7:52 pm

I think you're probably seeing a device driver issue. The USB drivers for the host chip on the Pi's SoC are...not good.

I've documented my troubleshooting in Over a month and no response from anyone involved with the RPi.

My solution was to use a wired mouse and keyboard, and give up on using my wireless Logitech mouse (which works fine on every other Linux machine it's every been plugged into)

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Re: smsc problems

Tue Jul 10, 2012 4:46 am

I am using a "Logitech EX cordless Desktop" Keyboard and Mouse Combo and having no problems. The rated usage is 55ma for the wirless receiver. Another Logitech wireless combo is 77ma and works well also.
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