On 01/11/2012 09:50 PM, Alan Stern wrote:
Assume that usb-storage does not
refuse to bind.
But my original question explicitly asked about what happens if
usb-storage _does_ refuse to bind. So did both of the follow-up
questions.
I can't test it easily right now. What I see with my UAS gadget is that
usb-storage tries to bind, refuses and then UAS is probing it.
I don't understand. Why can't you use CDC and storage at the same
time?
I though you can only use _one_ Interface at a time. Hmmm.
On any composite USB device you should be able to use multiple
interfaces at the same time.
Hmmm.
So I loaded
the g_multi driver. After that I loaded manually the storage driver and
was able to access /dev/sda.
Why did you need to load it manually? Doesn't the hotplug mechanism
load it automatically?
It does. It loaded all the driver and repeated to bind cdc-net and a
few others over and over again. So tried to load them by hand to see
when it starts to explode.
Next thing I did was loading the network
driver and I got usb0 and usb1. I set the ip address. After that I tried
to access dev/sda again and it hung:
[ 157.672942] usbcore: registered new interface driver cdc_ether
root@squsb:~# hexdump -C /dev/sda | head
That sounds like a bug.
[ 216.804125] cdc_ether 1-1:2.0: forced unbind
[ 216.804735] dummy_hcd dummy_hcd: shutdown urb deba5db0 ep3in-intr
[ 216.808351] cdc_ether 1-1:2.0: usb1: unregister 'cdc_ether'
usb-dummy_hcd-1, CDC Ethernet Device
[ 216.904273] hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002
[ 216.960175] usb 1-1: reset high-speed USB device number 2 using dummy_hcd
[ 217.020186] hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002
[ 217.124086] gadget: high-speed config #2: Multifunction with CDC ECM
Presumably these resets were caused by usb-storage timing out and
trying to recover.
This went for a while and then it ended with:
[ 254.459129] sd 0:0:0:0: Device offlined - not ready after error recovery
[ 254.461439] sd 0:0:0:0: rejecting I/O to offline device
[ 254.462150] sd 0:0:0:0: rejecting I/O to offline device
[ 254.462996] sda: unable to read partition table
That makes me think that I can not use two of those at the same time.
But I can use one of them at a time.
No, you definitely should be able to use two interfaces at the same
time. Something needs to be fixed. Did you try checking with usbmon?
Well. I learned now it is designed to use two interfaces at the same. I
did no know that. So let me try to investigate this later :)
Alan Stern
Sebastian
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