Poll: USB not working

Hardware related problems and workarounds

Are you unable to get USB working?

Yes
13
54%
No
11
46%
 
Total votes : 24

Re: Poll: USB not working

Postby ajtravis » Sun Aug 10, 2014 9:34 pm

teekai wrote:I purchased 2 boards thinking it would be fun to play around with it but up to this point I'm giving up on getting USB to work. I'm able to PuTTY in and install xrpd so I can remote in using windows client but it is soooooooo...........slow............I've tried hundreds of time with different combination of powered and unpowered USB hub and NO luck. I GIVE UP!

Hi, teekai.

Please don't give up - We can only get to the bottom of this problem if we keep trying to find out what is wrong.

I've had a *terrible* time trying to demonstrate Parallella with USB not working predictably. Most often, it works from a 'cold' start (i.e. when the PSU has been off for a while). I also suspect that the USB problem is worse when you enable the serial console, which is consistent with what Fred says in his message about USB problems. My view is that Parallella can't be used in a 'Desktop' computer configuration unless USB works reliably. Please hang in there and help us find out how to do that.

Bye,

Tony.
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Re: Poll: USB not working

Postby Morgaine » Thu Aug 14, 2014 8:35 pm

FHuettig wrote:We have since fixed that in the devicetree by removing the UART as the default console, and now I never see the PPPP any more.


That's only a "fix" in the sense that chopping off one's head would be a "fix" for dandruff. :D

The actual fault which causes PPPP when the UART is present still remains.

It may be true that losing the UART overcomes the PPPP problem, but the price is too high except as a temporary stopgap. Serial console is a facility of extreme value in a multitude of cases, and cannot reasonably be lost from the user's toolkit.

Morgaine.
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Re: Poll: USB not working

Postby aolofsson » Sat Aug 16, 2014 2:15 pm

Morgaine,
Most people don't have serial cables so it makes more sense to output kernel messages to screen. Folks who want to use a serial cable can always enable it by modifying device tree and using dtc to create a dtb file. I use both methods regularly.
Andreas
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Re: Poll: USB not working

Postby ajtravis » Sat Aug 16, 2014 10:52 pm

aolofsson wrote:Morgaine,
Most people don't have serial cables so it makes more sense to output kernel messages to screen. Folks who want to use a serial cable can always enable it by modifying device tree and using dtc to create a dtb file. I use both methods regularly.

Hi, Andreas.

Do you mean remove the "console=ttyPS0,115200" kernel boot parameter, or the actual UART device in the tree?

I'm concerned that the UART hardware might be compromising the USB PHY because when I remove the serial console from the boot parameters in the device tree it seems that the USB PHY is detected more often. I've left the serial cables attached to the 3-pin UART connector or disconnected them, but it doesn't seem to make any difference.

I realise that you have difficulty reproducing these USB problems, even on cards that have been returned to Adapteva, but I think it is causing serious damage to the credibility of Parallella as a desktop computer that USB can't be relied on 100% of the time. I have seen similar reports of USB PHY problems with the Zed-board too. In my case, I have four boards that all behave the same: I can't accept that this is because of a 'problem' board. I think there may be an underlying design issue causing the problem.

This is a depressingly familiar result after powering up my 4@SKU101020 cluster:
Code: Select all
node4:~> dsh -Ma -- lsusb
node1: unable to initialize libusb: -99
node2: unable to initialize libusb: -99
node3: unable to initialize libusb: -99
node4: unable to initialize libusb: -99


I don't believe that 'random' errors would cause all four of my boards to routinely fail to initialise their USB PHY resulting in failure of the Linux kernel to detect the USB port. I've built a new kernel (node1,4) and booted your headless kernel (node2,3):
Code: Select all
node4:~> dsh -Ma -- uname -a
node1: Linux node1 3.12.0-parallella-g71330d8 #1 SMP PREEMPT Wed Aug 13 01:45:12 UTC 2014 armv7l armv7l armv7l GNU/Linux
node2: Linux node2 3.12.0-g0bc9c3a-dirty #6 SMP PREEMPT Wed Jan 29 10:25:25 CET 2014 armv7l armv7l armv7l GNU/Linux
node3: Linux node3 3.12.0-g0bc9c3a-dirty #6 SMP PREEMPT Wed Jan 29 10:25:25 CET 2014 armv7l armv7l armv7l GNU/Linux
node4: Linux node4 3.12.0-parallella-g71330d8 #1 SMP PREEMPT Wed Aug 13 01:45:12 UTC 2014 armv7l armv7l armv7l GNU/Linux
node4:~>

I booted two of these nodes with, and two nodes without a console= kernel boot parameter:
Code: Select all
node4:~> dsh -Ma -- cat /proc/cmdline
node1: Kernel command line: root=/dev/mmcblk0p2 rw rootfstype=ext4
node2: Kernel command line: console=ttyPS0,115200 root=/dev/mmcblk0p2 rw rootfstype=ext4 rootwait
node3: Kernel command line: console=ttyPS0,115200 root=/dev/mmcblk0p2 rw rootfstype=ext4 rootwait
node4: Kernel command line: root=/dev/mmcblk0p2 rw rootfstype=ext4

I believe that Parallella has massive potential as a desktop computer, but not until we get to the bottom of this USB problem.

See also http://www.parallella.org/forums/viewtopic.php?f=23&t=1236&sid=188d5e39bc442c632b0a0a7e8bce4749

HTH,

Tony.
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Re: Poll: USB not working

Postby ka6s » Sun Aug 17, 2014 1:32 pm

I vote No.

I've seen it work exactly once. I have a relatively new board only having recieved it 3-4 weeks ago.

I'm guessing the reset sequence is indeed where the problem lays.

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Re: Poll: USB not working

Postby ajtravis » Sun Aug 17, 2014 2:00 pm

ka6s wrote:I vote No.

I've seen it work exactly once. I have a relatively new board only having recieved it 3-4 weeks ago.

I'm guessing the reset sequence is indeed where the problem lays.


Hi, Steve.

The wording of this poll (not mine) is confusing: "Are you unable to get USB working?"

Your vote "No" means you are "not unable" (i.e. you are able) to get USB working.

I think it might be less confusing to ask "Have you encountered problems with USB?" and give some details.

In my case, yes: USB works if the USB PHY is initialised, but very often it is not and then USB doesn't work.

Bye,

Tony.
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Re: Poll: USB not working

Postby shodruk » Sun Aug 17, 2014 4:40 pm

ajtravis wrote:I think it might be less confusing to ask "Have you encountered problems with USB?" and give some details.


NO!!!! WE SHOULD NOT USE THAT SENTENCE!!!!!!!
Because almost all the users may have encountered problems with USB at least once.
I had a problem with USB too, it was a configuration problem, and now I have no problem with USB.
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Re: Poll: USB not working

Postby ajtravis » Sun Aug 17, 2014 4:46 pm

shodruk wrote:
ajtravis wrote:I think it might be less confusing to ask "Have you encountered problems with USB?" and give some details.


NO!!!! WE SHOULD NOT USE THAT SENTENCE!!!!!!!
Because almost all the users may have encountered problems with USB at least once.
I had a problem with USB too, it was a configuration problem, and now I have no problem with USB.

Hi, shodruk.

The USB problem is real - Not just a configuration problem: Read Fred's posts about it.

Similar problems have been reported for the Zed Board too.

Bye,

Tony.
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Re: Poll: USB not working

Postby shodruk » Sun Aug 17, 2014 4:58 pm

I said, we should not use "that" sentence.

We should use,
"Are you unable to get USB working?"
or,
"Are you able to get USB working?"
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Re: Poll: USB not working

Postby ajtravis » Sun Aug 17, 2014 5:04 pm

shodruk wrote:I said, we should not use "that" sentence.

We should use,
"Are you unable to get USB working?"
or,
"Are you able to get USB working?"

Hi, shodruk.

Sorry, I misread your reply: I thought you were saying that the USB problems are just a configuration problem...

I find the double-negative in the original question confusing - Even though I'm from Lancashire ;-)

Bye,

Tony.
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