USB Problems

[wheelnut]

Hi,

I have received my raspberry pi and have read that some people have experienced the same issues as I have. What seems to be the problem here is that I use a USB keyboard and a USB wireless network card, along with the wired network. The keyboard starts out fine, and then intermittently drops or repeats characters. The wired network device also seem a little unreliable. It was suggested in one of the forums that there was a volts drop between TP1 and TP2, suggesting that it should read 5V d.c., but I was getting 4.79 V. The power supply that came with my Raspberry PI was rated at 1.2A at 5V, but not knowing the current requirements, I assumed that my existing supply was not powerful enough. So, I have a new one rated at 2.25A at 5V... same problem persists. The voltage across TP1 and TP2 is now 4.81 V... almost no difference.
I think I can safely say that electrical energy supply is not the problem here. Perhaps someone can advise as to whether or not there is a problem with the smsc95xx driver or the chip that handles the USB/Ethernet combination and what, if anything I can do about it.

Many thanks in advance,

Martin

[redhawk]

The voltage does drop when loaded unfortunately this depends in the design of power supply - http://www.raspberrypi.org/phpBB3/viewt ... 63&t=11898

Richard S.

[drgeoff]

See http://www.raspberrypi.org/phpBB3/viewt ... 09#p138109 and that whole "elephant in the room" thread.

I think there should be a big sticky on the raspberrypi.org site with a link to a list of all known problems. This and other already found issues seems to be re-asked in the forum every day.

[lostintime]

See http://www.raspberrypi.org/phpBB3/viewt ... 09#p138109 and that whole "elephant in the room" thread.

I think there should be a big sticky on the raspberrypi.org site with a link to a list of all known problems. This and other already found issues seems to be re-asked in the forum every day.

Good idea. But since that would be admitting that there is a major problem with the Raspberry Pi I don't think it'll happen.

[itimpi]

You mention a USB wifi network card, but not which one it is. Many models attempt to draw more current than the Pi can supply and will only work if connected via a powered hub.

[drgeoff]

You mention a USB wifi network card, but not which one it is. Many models attempt to draw more current than the Pi can supply and will only work if connected via a powered hub.

True, but if that was the only cause a perfectly working keyboard would not begin to drop characters.
Using some keyboards/mice plugged in to hubs seems to be problematic as well. Lots of post on that and acknowledged in the post from gsh that I point to in my answer above.

[lostintime]

I have received my raspberry pi and have read that some people have experienced the same issues as I have. What seems to be the problem here is that I use a USB keyboard and a USB wireless network card, along with the wired network. The keyboard starts out fine, and then intermittently drops or repeats characters. The wired network device also seem a little unreliable. It was suggested in one of the forums that there was a volts drop between TP1 and TP2, suggesting that it should read 5V d.c., but I was getting 4.79 V. The power supply that came with my Raspberry PI was rated at 1.2A at 5V, but not knowing the current requirements, I assumed that my existing supply was not powerful enough. So, I have a new one rated at 2.25A at 5V... same problem persists. The voltage across TP1 and TP2 is now 4.81 V... almost no difference.
I think I can safely say that electrical energy supply is not the problem here. Perhaps someone can advise as to whether or not there is a problem with the smsc95xx driver or the chip that handles the USB/Ethernet combination and what, if anything I can do about it.

Are you using a hub? The drivers for the USB controller in the Raspberry Pi are very buggy and don't work properly with hubs and most likely never will.

Buy a USB Y cable like this one: http://www.ebay.com/itm/UT-STARCOM-DATA ... 0629544153 and plug your Wi-Fi adapter into it, then plug the power only side of the Y into a powered hub and the other side of the Y into your Pi. The hub should NOT be connected to your Pi. Doing this both avoids the Pi's problems with hubs and also lightens the electrical load on the Pi.

[wheelnut]

Yes, I am using a hub and it works well with my other computer equipment and I have read that there are problems with many hubs, however, I have to admit, I had not even considered a "Y" cable. I will obtain one of these and try it out. Many thanks - I will post the results of this and let everyone know. In the meantime, the USB wireless card that I am using is a Sitecom WL-536 - not sure what it's power requirements are, but as "lostintime" recommends, I will get the "Y" cable and see.

Many, many thanks for all of your replies and insights.

Martin

[ph0ng]

So, I have a new one rated at 2.25A at 5V... same problem persists. The voltage across TP1 and TP2 is now 4.81 V... almost no difference.

Please observe the difference between current and voltage. The EU micro-USB charger standard permits 5% tolerance on output voltage. This means that everything in the [4.75V ... 5.25V] range is allowed.

I was having similar problems (as well as network hangs) with 4.80V over TP1 and TP2. Finally I equipped a good power supply with a micro-USB connector and have 5.01V TP1-TP2. Since then I have been running my Pi for 8 days straight without any problems (used to see problems at least once a day earlier).

Has the foundation acknowledged the problem with insufficient EU compliant chargers? I think the "700mA / 5V" charger recommendations are way too simplified.

[spitecho]

A different keyboard might actually help. I had the exact same problems with both a Logitech Illuminated keyboard and an Apple A1048 with built-in USB ports--lost or stuck keypresses, dropped internet connection. Even with a powered hub.

Then I tried a Logitech Classic Keyboard 200 and all the problems just stopped. Even with a wireless mouse and external HD torrenting and streaming video, I was able to browse in Midori with no keyboard or ethernet problems whatsoever.

[ferrymanr]

Even with a wireless mouse and external HD torrenting and streaming video, I was able to browse in Midori with no keyboard or ethernet problems whatsoever.

Interesting result. Can you elaborate a little. What hub are you using? Which device is plugged into the other RPi USB port? Does it make any difference if the hub is on the lower or upper RPi USB port? What sort of hub/router is connected to the network port? I get the impression from my tests that these factors all have a big influence on stability.

[spitecho]

The hub is a black 4-port D-Link DUB-H4 with a 2.5A AC adapter. Plugged into the hub is a Logitech wireless mouse dongle, a Toshiba Canvio USB 3.0 external HD and the Pi itself (using a microUSB Kindle cord). The ethernet is plugged into a Netgear RP614v4 router. It doesn't seem to make a difference if the hub or keyboard are plugged into the lower or upper port. The second port on the Pi has the keyboard plugged into it, but it also works plugged into the hub.

Odd side note: When I was used the Logitech Illuminated or Apple keyboards without a USB hub, the internet connection never dropped, and the keyboards would work fine until I tried actually using the internet--then the keys would stick and not register being pressed. However, with a hub, ethernet wouldn't work at all and the keyboard was as screwy as ever. And that was with the Pi using a separate 1A power supply. Having the hub plugged in actually caused more problems for some reason. But with the classic keyboard, everything works fine now.

[ph0ng]

spitecho: That sounds alot like a power issue to me. When you used an illuminated (high power) keyboard, the total system current increased and hence the voltage drop over the input polyfuse F3 increased. If your power supply delivers 4.8V, and you drop 300mV over F3 (taking 600mA / 0.5Ohm as an example) you would end up with 4.5V TP1-TP2.

This is independent of the amperage rating of your power supply! Could someone please tell me if the foundation is planning on giving new recommendations or update the current power design?

EDIT: This answer is about spitecho's findings.

[spitecho]

ph0ng: But why would a powered hub not solve that? One thing I did notice was that both wonky keyboards registered as full-speed USB devices in dmesg, and the working keyboard came up as low-speed. If anyone has a full-speed non-swanky keyboard (no lights, USB ports, etc.), it might be worth looking into.

By the way, if anyone else is still struggling with sticking keys, I recommend trying Synergy as a temporary fix. It lets you use a single keyboard and mouse between multiple computers over the network. Just sudo apt-get install quicksynergy and run a PC as the server and a Raspberry Pi as a client.

[ph0ng]

I was referring to this:

Plugged into the hub is a Logitech wireless mouse dongle, a Toshiba Canvio USB 3.0 external HD and the Pi itself (using a microUSB Kindle cord). The ethernet is plugged into a Netgear RP614v4 router. It doesn't seem to make a difference if the hub or keyboard are plugged into the lower or upper port. The second port on the Pi has the keyboard plugged into it, but it also works plugged into the hub.

As I interpret the text, you have the keyboard connected directly to the Pi port, meaning that you draw current from it regardless of how you supply the Pi itself. My reasoning then goes like this:

1) Assume both the old power supply and the hub delivers a fixed voltage V_in
2) Assume the keyboard draws a fixed current I_kbd, the rest of the system I_sys
3) The system voltage after the F3 drop is then V_sys = V_in - R_f3 * (I_sys + I_kbd)

I suspect that the backlit keyboard draws more current than the standard one.

[spitecho]

Ahhh, no, I have the working keyboard currently directly plugged into the Pi, but the other two I tried in the hub and in the Pi with the same results. And turning the backlight off on the keyboard made no difference. The wiki also lists my particular Apple keyboard as working with a hub, but alas, no dice.

Gsh in the Elephant thread says he's traced it back to a kernel issue, so fingers crossed that it'll be software-fixable.

[Dangerous1]

I am using a D-Link USB powered hub DUB-H4 which is on the list of usable hubs.

I use the hub to supply the power to the R-PI and then connect one of the PIs USB to the USB input of the hub. This leaves me with tree available USB ports on the hub (avoiding using the second USB on the R-PI).

I have installed all the required packages to run a GMSK radio interface and a WiFi dongle (TPLINK).
Each will run perfectly indivudualy but not together.

Because the only current drain on the R-PI is the USB input to the powered hub (on approved list) I cannot see the problem being current/voltage-drop related, it seems to be more of a 'clash' between usb management resources, but am no expert.

Dangerous1

[kg001]

Hi All

I am having similar issues with USB devices & have spent quite a bit of time now looking at the problem. I am using a powered Zipp 7 port hub & a small el-cheepo (dollar store 4 port hub modified too be externally powered. The power supply is a solid 3amp unit Mounted 2 inches from the PI. outputting 5.04V regardless of load. I have tried all sorts of combinations of Keyboards / mice /hubs/ with varying degrees of success. The things I have observed so far are that
1. Slower devices seem to have more issues i.e. a wireless mouse (USB2) gave less problems than a USB1.1 Mouse Ditto with Key boards.
2. No matter what I did eventually the keyboard would start sticking or repeating, The mouse would occasionally drop off & the USB drives would drop off. during all of this I was using the LXE desktop
3. Over the last week I have been playing with setting the PI up as a NAS box & working at the command prompt with the desktop closed & have not had any USB related issues What so ever.
4. The pi will run with 720p HDMI sound & video via OMXPLAYER & function simultaneously as a NAS box flawlessly, Providing the desktop environment is not open.

My suspicions at this stage are that there could be time-out issues with the USB ports when the processor is highly loaded. Or that the 5V supply rail was sagging under CPU loading.

To my surprise a recording volt meter on TP1 TP2 showed the 5v rail wandering between 4.766V and 4.866V dependant on CPU/GPU load while the power supply stayed rock steady at 5.04V Throwing suspicion on the usb power lead & the USB plug & socket.

Next steps will be to find another USB lead I can sacrifice the the Rasperian Gods & hang a digital CRO across TP1/TP2 & look for high speed glitches.

more later KG001

[drgeoff]

@KG001. Have a read of the "USB Elephant in Room" thread here in this Troubleshooting section.

[ph0ng]

To my surprise a recording volt meter on TP1 TP2 showed the 5v rail wandering between 4.766V and 4.866V dependant on CPU/GPU load while the power supply stayed rock steady at 5.04V Throwing suspicion on the usb power lead & the USB plug & socket.

This is perfectly normal (though not the smartest design choice) since the voltage drop over F3 is proportional to the current according to Ohm's law.

If you are willing to void warranty, you may bypass F3 (or mount a pptc with higher current rating and lower on resistance). All of my usb and ethernet problems disappeared when I started using a 5.15V supply, after which the F3 drop was compensated for and TP1-TP2 never went below 4.90V.

[kg001]

Thanks for that.

Further to my previous post I jumpered past the polyfuse etc & fed the PI a rock solid 5V, and while the USB issues seemed to improve somewhat it still fell over after a while when the desktop environment was running. I tried running it with 'rtorrent' command line bittorrent client. & found that the pi claged out after a while if it was being kept to busy, even without the GUI open . The crazy thing is that I can max out the processor for days on end without any sign of a problem doing things like hailstone calculations, the only difference is that there is no USB/Network traffic while doing that.
My second ras-pi arrived in the post earlier today so as soon as I can get time I will run that one up under the same conditions & see if it behaves the same just in case I have struck a hardware fault.

[kg001]

Thanks for the advice Guys.

I haven't tried the second Pi yet however I found this link towards the end of the USB ELEPHANT IN OUR ROOM post
crash under load - fix: viewtopic.php?f=24&t=14394&p=148684#p148684
the crashing under load problems are gone, and with the voltage issues fixed albeit temporally the usb issues are also banished. Granted the performance is horrible with the desktop environment active but I have currently got rtorrent sucking about 4Mbit off the net & simultaneously running the PI as a NAS box with no issues, That makes me one happy camper. My only wish is that some of the wingers would display a bit of patience & treat this whole thing as a joint adventure. Lets face it in the very recent past we have seen a raft of unanticipated issues fixed & personally I have learnt more about Linux & than in 10yrs as a heavy Lindows/Linspire/Ubuntu user and had as much fun as when I got my first code to run on an OSI super board back in 197?

Cheers & Thanks NevB

[kg001]

The link didn't paste correctly so here is the text of the post I referred to
| by elatllat » Mon Aug 13, 2012 11:26 am
| Please add "smsc95xx.turbo_mode=N" to /boot/cmdline.txt in the official image, it prevents
| the rpi from crashing under load.
| Also prevents the log from filling with this:
| CODE: SELECT ALL
| smsc95xx 1-1.1:1.0: eth0: kevent 2 may have been dropped
It works with both the Raspian & Debian Images

Cheers NevB Kg001

[RaTTuS]

http://www.raspberrypi.org/phpBB3/viewt ... 84#p148684