Pi USB Saga – An Embarrassing Fail.. – and a Warning!
I had got tired of trying all the so-called ‘recommendations’ for fixing USB hub connectivity on the Raspberry Pi – including some from people who did not actually own one.. And yes, I do have the correct voltage power supply etc. etc…
So – I was happy to see that there was -at least – a potential hardware fix, involving the addition of 1 Ohm resistors in parallel with the corresponding USB fuses on the board..
I went down to the local electronics store, and bought some ‘1 Ohm’ resistors, and went ahead and soldered them in place – a bit of a fiddly job, and not helped by the ‘lead-free’ solder not ‘wetting’ very well..
After all that, I plugged everything back together, but was then dismayed to see that the problem still persisted:
hub 1-1.3.2:1.0: hub_port_status failed (err = -110)
hub 1-1.3.2:1.0: hub_port_status failed (err = -110)
hub 1-1.3.2:1.0: hub_port_status failed (err = -110)
hub 1-1.3.2:1.0: hub_port_status failed (err = -110)
hub 1-1.3.2:1.0: hub_port_status failed (err = -110)
hub 1-1.3:1.0: hub_port_status failed (err = -110)
hub 1-1.3:1.0: hub_port_status failed (err = -110)
hub 1-1.3:1.0: hub_port_status failed (err = -71)
usb 1-1.3.2.1: USB disconnect, device number 16
hub 1-1.3:1.0: cannot reset port 2 (err = -71)
hub 1-1.3:1.0: cannot reset port 2 (err = -71)
hub 1-1.3:1.0: cannot reset port 2 (err = -71)
hub 1-1.3:1.0: cannot reset port 2 (err = -71)
I was – to say the least – disappointed, but then decided to do the usual Kepner-Tregoe thing, and check all the things I had changed, so far..
I was embarrassed to discover that the ‘1 Ohm’ resistors I had been sold, and marked as ‘1 Ohm’ on the bag they came in, were nothing of the sort! According to the colour coding (which – in hindsight – I should have taken with me to the store..) they were about 0.16 Ohms, which probably explained why they were somewhat ineffective!
I did find a rather useful site that has a visual calculator/display for these colour-codes:
http://www.qsl.net/w/wy3w/3938/CALCTEST/resistance_calculator.htm
So – back to the drawing board, and I shall have to unsolder everything, and try again!
I would like to share my experience and problems with a generic usb sound card plugged into the usb port of Raspberry pi.
The USB sound card(C- media vid 0x0d8c pid 0x000e) responds properly to aplay command ONLY if it is inserted into the port AFTER boot up.
If it is left connected to the port and the power is applied, it does not respond to aplay command. (meaning it does not play the .wav file)The error reported is
aplay: hw_parms 1145: unable to install hw params:
The only way to make it work again is to remove it and reinsert it.
I have posted this in the Raspi forum a week back but there is no solution sofar.
my OS is
Linux raspberrypi 3.1.9+ #168 PREEEMPT Sat Jul 14 18:56:31 BST 2012 arm6l GNU/Linux
Please forgive me if this is the wrong place to leave the above comment.
Yes, as far as I can tell, the Pi USB connection does not meet the USB spec.. I will try the hardware fix again, as soon as I get the correct resistors…
In my experience, ANY USB1.1 device (full-speed and low-speed) throws the dwc_otg driver in disarray. USB sound devices usually come in USB1.1 flavour, as yours probably is, and it’s quite a search to find a USB2.0 one..
Well, as far as I am concerned, USB is broken on the Raspberry Pi. There is a revised version of the board coming out, which is claimed to be ‘really no different’ to the original hardware, but does appear to have the ‘fuses’ removed?
Yes, but the fuses are just another design flaw. Obviously, the whole thing is utterly broken. Foremost the USB in the SOC, which is some third-party IP bought by Broadcom. And even those Broadcom engineers don’t have a clue what’s going on. Don’t expect the thing ever to be working reliable. What a waste of time and money.
USB is a problem, but from my experience, everything else works just fine… The design is an engineering compromise, to achieve a balance of functionality vs low cost-of-ownership, and in that, it has been a great success..