On Wednesday, 4 January 2017 15:50:00 GMT Ralph Corderoy wrote: > > It turns out that the problem seems to be that the Hub is connected > > via a USB port on the Pi (the only one in the case of the Zero). It > > looks like that port cannot handle the conflicts when all the Audio > > Adaptors shout at once. > > I don't see a strong indication that's the cause? What conflicts?
Well OK. I am surmising that there are conflicts when the three devices are all shouting. > The different Pis have different USB hardware, and different Linux > drivers to talk to them IIRC. And those drivers change over time. Try > a distro with a dramatically different kernel version, like an old one. > It will be another data point. This problem occurs with a Zero, a Pi 2 and a Pi 3, so I'm discounting the hardware at the moment. I am using the same SD card running Raspbian Jessie on all three. The problem only occurs (and it occurs every time) if I try to connect the hub through one USB port. I will have a look at using an old distro, but the fact that the Adaptors work OK when they are accessed through separate USB ports seems to preclude driver issues to me. Maybe I'm wrong. > Also, I think `journalctl -f' might be interesting to watch as you do > things. You can tap Enter to give you a bit of blank space now and > again so you can see what's new. You can try doing this over an SSH > connection to the Pi for when you run `startx', but given networking is > also over the Pi's USB port I'd really recommend you use the Pi's serial > port and set the Linux console to use that. Cables are available. > > http://elinux.org/RPi_Serial_Connection > http://amzn.to/2iAd006 I tried SSH. As predicted the Pi is inaccessible. I could pay for a third of a Pi 3 for the cost of one of those leads :-) > Other thoughts: startx(1) will prod USB as well as creating CPU load > causing the ARM to draw more power as its frequency increases. Try and > create a CPU load some other way; this should make one core busy and > you can run it in the background so you can kick off one per core if > need be. Wouldn't that also be a problem when the Adaptors are plugged directly into the Pi? > gzip -9 </dev/urandom >/dev/null > > Check `dmesg' output. `dmesg -w' will wait for new output, similar to > journalctl above. Will need the £11 cable to do those things. > Replace the audio USB adapters with other devices that will want > significant current to see if it helps spot when it's the £3 Chinese > audio USBs or a power issue. Yes. Paul says that he has some USB speaker-phone adaptors that I can borrow. Otherwise, I suppose I could scrape together some USB hard disks, but they tend to be self-powered, so not necessarily conclusive if they work. I've now raised this on the Raspberry Pi Forum, so my next move is to see what they say. -- Terry Coles -- Next meeting: Bournemouth, Tuesday, 2017-02-07 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread: mailto:[email protected] / CHECK IF YOU'RE REPLYING Reporting bugs well: http://goo.gl/4Xue / TO THE LIST OR THE AUTHOR
