[kwlug disc.] USB versions on Linux

Fri Jun 1 22:13:06 EDT 2007

>From a non-Linux perspective, i.e. USB only ...

The card is worthwhile.

The card will be configured / appear as one or more hubs. Thus when
you connect devices, you will see ehci0/device0, ehci0/device1,
ehci1/device0, sort of thing.

Some hubs, and I forget the reference / criteria, cause all devices to
transmit at the same speed as the lowest speed device. So, connect a
mouse, keyboard, and camcorder, and you won't be happy.

Better hubs will segregate off the 1.1 traffic so when the camcorder
runs, it gets the 2.0 bandwidth. Even better hubs segregate multiple
1.1 devices better still.

Seems to me there were 3 sorts of connections, low speed 1.1, high
speed 2.0, and streaming, which are 2.0 and will gobble up the bandwidth.

For purposes of your test:
- plug key directly into computer and whale away at it. Is everything
cool?
- unplug key and plug hub in - ONLY. Is it seen as 2.0?
- plug key in to hub, is it still 2.0? Whale away on it.
- plug next device in, is it still 2.0. Repeat.
  - is there some point at which the hub slips down to 1.1?
    - i.e. stops being an ehci device and appears as an ohci device?
  - somewhere in here, keep whaling on it and see if you can spot the
point at which your glitch happens.

In general:
- fewer hubs the better
- don't plug more than 1 1.1 device in per hub.
- don't combine streaming devices such as camcorders and video call
cameras into the same hub.
- for reasons only the computer gods know, there are times when
devices will not be detected / work off the hub, but do off the ports
on the computer, including the internally connected ports that I wire
to my 'media centre' doohickey that gives me an additional 2 front
mounted usb ports.

Watch out for 'green' USB ports. In the sense that they shut down when
the computer shuts down (or the other way around), while the others
stay powered throughout. It is only supposed to matter, for example,
when charging your phone via usb cable and the computer is off.
Supposed to matter. It's been my experience that something more than
that is going on as I've experienced inexplicable strangeness between
green and non-green ports. Which is only to say ... you might see if
you get differing results between the two types of hubs.

And I've just generally experienced inexplicable strangeness with USB
that irritates me throughout.

But not nearly as bad as my firewire experience, which I've just given
up on.

Paul Nijjar wrote, On 6/01/2007 3:33 PM:
> On Fri, 1 Jun 2007, Daniel Agar wrote:
> 
>> You could check to see which modules are loaded (lsmod). EHCI is for usb
>> 2.0 and UHCI will be loaded for USB 1.0. If you have USB 2.0 ports you
>> should see both modules under lsmod.
> 
>     That is a good suggestion. I will try that.
> 
>     I did look around for some other information about USB. I learned
> that lsusb -v is my friend, as is /proc/bus/usb/devices. Below is the
> output from the latter. The "Ver=" lines below seem to indicate that
> Linux thinks my hub (i.e. the ports on my machine) are USB 1.1, and my
> new USB Key (the Kingston DataTraveler) is USB 2.0. So Linux should be
> smart enough to transmit at slower speeds, no?
> 
>     My questions now:
>     0. Is there a good way for me to stress test the USB key and/or
> ports? I have been transferring big files back and forth, which is how
> got the first lockup, but so far I haven't had success in reproducing it.
> 
>     1. Consider the following hypothetical situation: I go mug somebody
> and use the cash in that person's wallet to purchase a PCI card with
> some USB ports, like the following:
> 
> http://www.canadacomputers.com/index.php?do=ShowProduct&cmd=pd&pid=003053&cid=IO.313
> 
> 
>     The webpage suggests that despite the cute manufacturer name, the
> product is only for Windows. What chances of success would I have trying
> to get this working under Linux? Are there special drivers I would need
> to modprobe?
> 
>     2. Does it make sense to even consider getting such a PCI card? If
> my existing USB ports/hub is flaky, would this improve things?
> 
>     Incidentally, my kernel is 2.6.8, a stock Debian kernel for Sarge.
> 
> ---
> 
> [11:34 PM]ulcer:/proc/bus/usb$ less devices
> 
> T:  Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 2
> B:  Alloc=  0/900 us ( 0%), #Int=  0, #Iso=  0
> D:  Ver= 1.10 Cls=09(hub  ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
> P:  Vendor=0000 ProdID=0000 Rev= 2.06
> S:  Manufacturer=Linux 2.6.8-2-386 uhci_hcd
> S:  Product=VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller
> S:  SerialNumber=0000:00:07.2
> C:* #Ifs= 1 Cfg#= 1 Atr=c0 MxPwr=  0mA
> I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub
> E:  Ad=81(I) Atr=03(Int.) MxPS=   2 Ivl=255ms
> 
> T:  Bus=01 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#=  2 Spd=12  MxCh= 0
> D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
> P:  Vendor=13fe ProdID=1d00 Rev= 1.00
> S:  Manufacturer=Kingston
> S:  Product=DataTraveler 2.0
> S:  SerialNumber=5B741B939044
> C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=200mA
> I:  If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
> E:  Ad=81(I) Atr=02(Bulk) MxPS=  64 Ivl=0ms
> E:  Ad=02(O) Atr=02(Bulk) MxPS=  64 Ivl=0ms
> 
> 
> -- 
> Paul Nijjar - http://www.fairvotecanada.org/WaterlooRegion
> Next electoral reform info night: Tuesday June 12, 7pm
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