USB Issue Troubleshooting

Hardware related problems and workarounds

Re: USB Issue Troubleshooting

Postby ArunD » Mon Jun 22, 2015 3:03 pm

Hi, Tony...

Good reminder that I need to include more info.

* Failure mode (sometimes or always?)
More often than not. I think the problem does not present on warm boot if the previous instance did not present the problem. But on cold boot there does not seem to be any consistency.

* Headless/hdmi configuration
Headless configuration

* FPGA/Linux/Ubuntu version being used
Welcome to Linaro 14.04 (GNU/Linux 3.14.12-parallella-xilinx-g7a0dc64-dirty armv7l)

* Fan used?
Yes. It's powered from external power supply https://www.amazon.com/gp/product/B000I5KSNQ/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

* SKU#
P1601-DK03

* For SKU A101040 boards owners, an indication whether the U13 device is populated
Not applicable.

* Power supply used
The 5V/2A power supply that was packaged along with Parallella board product.

* Recommended: A picture of your USB setup (as shown here)
parallella-setup.jpg
parallella-setup.jpg (170.39 KiB) Viewed 12123 times



ajtravis wrote:
ArunD wrote:[...]
What can I do now to help resolve this for myself as well as for Adaptive, what is the more effective choice? [/u][/b]

As an individual buyer, I have put my own money towards this purchase, and as a work around, getting the embedded version is a out of my budget at this time.


Hi, ArunD.

You can do what Adreas asked and report your USB problems in a standard way, so Adapteva can get a more accurate picture of the USB problem: https://parallella.org/forums/viewtopic.php?f=50&t=1650&start=60#p10185.

If anyone else also has USB problems, but has not yet reported them to Adapteva, please post a message here using the format Andreas suggested.

Thanks,

Tony.
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Re: USB Issue Troubleshooting

Postby xilman » Mon Jun 22, 2015 4:21 pm

ajtravis wrote:
xilman wrote:Well, I had to bang some of the CLIP4R processor cards in the VME rack with the blunt end of a BIG screwdriver to get them to work (on the expert advice of the electronics design engineer I was working with). Sometimes, it feels horribly familiar trying to get the Parallella USB interface to work, but I've not (yet) tried banging them with a BIG screwdriver handle!

While we're swapping tech support war stories, I had two techniques for restarting dead HDDs for long enough to be able to get the data off them. One was to belt them along the spindle with a BIG screwdriver handle or a rubber mallet depending on which nearest to hand. The other was to put them in the freezer overnight. Both, of course, were intended to overcome stiction in the mechanics and/or re-seat a dry joint. Both had a suprisingly high success rate. Neither, I suspect, will have any success with the Parallella USB problem.

Your point about RMA is well-taken but the cost of doing it is likely prohibitive outside the US. Hard for me to see what can be done about this. Do I pay for international shipping on the off-chance that my boards work perfectly on the other side of the pond and/or their replacements fail on this?

I fear that your real message is close to the mark. Epiphany may well yet go the way of the Transputer if reliable hardware and easy to use software are not simultaneously available. I recognize that Adapteva are trying hard with limited resources but ...

Paul
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Re: USB Issue Troubleshooting

Postby tnt » Mon Jun 22, 2015 4:48 pm

I'm not exactly sure what people are still discussing here ...

AFAICT from the history of this thread, the issue has been diagnosed. The ULPI PHY sometimes comes out of reset in a weird state where it's not responsive despite being provided with a clean reset pulse. The design used the Xilinx recommended PHY and is connected properly so it _should_ work. Obviously it doesn't (or not reliably for some people) so the failure lies either with Xilinx's zynq doing weird stuff on the pin pre-boot or with the PHY behaving strangely sometimes, but at this point it really doesn't matter all that much.

Given that none of this is under software control, I don't see how a firmware upgrade or FPGA bitstream upgrade alone would do anything. The only solution seems to be to extend the reset pulse of the PHY about 100ms longer than the one from the PS (so that the FSBL has had time to properly configure the pins) and this will require some hw mod. The question is how to achieve that in the easiest way possible.
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Re: USB Issue Troubleshooting

Postby ajtravis » Tue Jun 23, 2015 2:24 pm

tnt wrote:I'm not exactly sure what people are still discussing here ...


Hi, tnt.

Well, I for one am trying to encourage Adapteva not to ignore the USB Elephant in the Parallella room...

AFAICT from the history of this thread, the issue has been diagnosed. The ULPI PHY sometimes comes out of reset in a weird state where it's not responsive despite being provided with a clean reset pulse. The design used the Xilinx recommended PHY and is connected properly so it _should_ work. Obviously it doesn't (or not reliably for some people) so the failure lies either with Xilinx's zynq doing weird stuff on the pin pre-boot or with the PHY behaving strangely sometimes, but at this point it really doesn't matter all that much.


Yes, and Fred did agree that there *is* a problem with USB initialisation http://forums.parallella.org/viewtopic.php?f=50&t=1510&p=10335#p10335

Given that none of this is under software control, I don't see how a firmware upgrade or FPGA bitstream upgrade alone would do anything. The only solution seems to be to extend the reset pulse of the PHY about 100ms longer than the one from the PS (so that the FSBL has had time to properly configure the pins) and this will require some hw mod. The question is how to achieve that in the easiest way possible.


We now have a R-Pi camera bounty - I suggested a Parallella bug bounty a while ago https://parallella.org/forums/viewtopic.php?f=8&t=1709, so @Adapteva, how about a USB bounty too?

Bye,

Tony.
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Re: USB Issue Troubleshooting

Postby ajtravis » Tue Jun 23, 2015 2:50 pm

xilman wrote:[...]
While we're swapping tech support war stories, I had two techniques for restarting dead HDDs for long enough to be able to get the data off them. One was to belt them along the spindle with a BIG screwdriver handle or a rubber mallet depending on which nearest to hand. The other was to put them in the freezer overnight. Both, of course, were intended to overcome stiction in the mechanics and/or re-seat a dry joint. Both had a suprisingly high success rate. Neither, I suspect, will have any success with the Parallella USB problem.


Hi, Paul.

For those who might not know, 'stiction' (static friction) is a made-up word used by Sun Engineers to describe what happens when traces of lubricant leak out of the spindle bearing of an (old) hard disk drive and 'stick' the heads to the landing zone of the platter. The official Sun field-service guide to overcome 'stiction' was to stand the drive on the corner opposite the actuator and let it to drop onto a hard surface. Not tried this with my Parallella boards yet, but I've come close...
Your point about RMA is well-taken but the cost of doing it is likely prohibitive outside the US. Hard for me to see what can be done about this. Do I pay for international shipping on the off-chance that my boards work perfectly on the other side of the pond and/or their replacements fail on this?


I think it is fair/normal for the cost of RMA shipping to be shared in these circumstances, but I've ended up doing exactly what you describe.

I fear that your real message is close to the mark. Epiphany may well yet go the way of the Transputer if reliable hardware and easy to use software are not simultaneously available. I recognize that Adapteva are trying hard with limited resources but ...


I keep returning to the notion that Adapteva brought these boards to us practically at cost and I do understand that there are limits to the time they can invest in finding a solution to technical problems that don't prevent the card being used in an embedded application, for example. However, adding the non-existent eLink cables to the USB problems means that, for me, Parallella can't be used as a 'desktop' computer or as a mesh-connected 'cluster. Simply connecting four Parallella boards together by their Gbit NICs and a switch (at extra cost) is not really what was promised during the Kickstarter campaign.

I went back to visit the research group where I worked on CLIP4R ten years later only to discover that one enterprising engineer had done a roaring trade drilling a hole in the middle of the array processor circuit boards and turning them into wall-clocks. A sad end to what was a very interesting project. Let's hope we don't end up selling Parallella wall-clocks on eBay just to get some of our money back :-(

Bye,

Tony.
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Re: USB Issue Troubleshooting

Postby tnt » Tue Jun 23, 2015 3:12 pm

AFAIK you can use the porcupine to connect two boards together via the elinks ? There are 2 connectors for each PEC that can be used with standard 2mm pitch IDC cables.
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Re: USB Issue Troubleshooting

Postby ajtravis » Tue Jun 23, 2015 3:21 pm

tnt wrote:AFAIK you can use the porcupine to connect two boards together via the elinks ? There are 2 connectors for each PEC that can be used with standard 2mm pitch IDC cables.


Hi, tnt.

Yes, I know - Just bought four Porcupine 2 boards from DigiKey - I do still believe in Parallella :-)

However, we won't get high-speed interconnects on IDC connectors: I spent quite a lot of time pricing up a hi-spec cable from Samtec, but gave up when Fred explained to me how much 'swizzling' he had to do on the Porcupine to bring the signals out to the connectors in a rational layout for straight-through cable connections between boards. Fred told me that Adapteva have done some preliminary experiments interconnecting Epiphany chips via the Porcupine 2 N/S breakout connectors, but that's all I know. I'm still looking for high-quality IDC connectors and ribbon cable just now... @Fred any recommendations?

Bye,

Tony.
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Re: USB Issue Troubleshooting

Postby tnt » Tue Jun 23, 2015 3:37 pm

ajtravis wrote:However, we won't get high-speed interconnects on IDC connectors: I spent quite a lot of time pricing up a hi-spec cable from Samtec, but gave up when Fred explained to me how much 'swizzling' he had to do on the Porcupine to bring the signals out to the connectors in a rational layout for straight-through cable connections between boards. Fred told me that Adapteva have done some preliminary experiments interconnecting Epiphany chips via the Porcupine 2 N/S breakout connectors, but that's all I know. I'm still looking for high-quality IDC connectors and ribbon cable just now... @Fred any recommendations?


It's source synchronous LVDS, it's pretty resilient. AFAICT, the max clock is 300 MHz DDR anyway. ( fclk / 2) which definitely sound possible to do on a short LVDS run. You should see my current hacked up cable for the RPi camera, it's pretty horrible and works fine at 200 MHz DDR.
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Re: USB Issue Troubleshooting

Postby ajtravis » Tue Jun 23, 2015 4:03 pm

tnt wrote:[...]
It's source synchronous LVDS, it's pretty resilient. AFAICT, the max clock is 300 MHz DDR anyway. ( fclk / 2) which definitely sound possible to do on a short LVDS run. You should see my current hacked up cable for the RPi camera, it's pretty horrible and works fine at 200 MHz DDR.


Hi, tnt.

Well, how fast the eLink is depends what you think 'effective' bandwidth means: http://www.adapteva.com/epiphanyiii/

Off-Chip IO:
The eMesh network and memory architecture is extended off-chip using source synchronous LVDS based serial links that provide up to 2GB/sec of effective bandwidth per link. Each E16G301 has 4 links, one in each direction (north, east, west, south), allowing chips to be easily interfaced with FPGAs and/or other E16G301 chips on a board.


Anyway, it was Fred who told me their experiments were at 'relatively' low speed - Not tried it myself yet!

Bye,

Tony.
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Re: USB Issue Troubleshooting

Postby njpacoma » Sun Jun 28, 2015 12:44 am

Adding myself to the list of people having problems.

* Failure mode (sometimes or always?)
99% failure (I have gotten USB to work once with the headless and once with the HDMI configurations.)

* Headless/hdmi configuration
Both.

* FPGA/Linux/Ubuntu version being used
headless: Linux parallella 3.14.12-parallella-xilinx-g40a90c3 #1 SMP PREEMPT Fri Jan 23 22:01:51 CET 2015 armv7l armv7l armv7l GNU/Linux

* Fan used?
Yes.

* SKU#
P1601-DK03, SN 0010680

* Power supply used
Supplied with kit ordered from Amazon.

I have had my Parallella for less than 1 week. I have had the USB problem since day 1. I have tried many different setups and workarounds from the comments in this thread. While I am sufficiently interested in this system to use it headless, I am disappointed that this problem still exists without a real solution. A problem of this significance could really impact the acceptance and adoption of this very interesting and useful product.
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