Hi David,
Thanks for your detailed reply.
David Brownell wrote:
> On Tuesday 02 January 2007 4:35 am, Phil Endecott wrote:
>> How should a gadgetfs application cause an ACK to be sent to the host
>> in response to a sucessfully received and processed control out transaction?
> Modulo hardware interface botches which will in at least one case (AT91)
> preclude this for gadgetfs, the status stage should start automatically
> when all the data has been read. So: issue a read (this is OUT) for
> N (>0) bytes, and the underlying controller driver should automatically
> start the STATUS stage of the control transfer.
OK. I understand this now. Earlier, I was seeing the host time out
and assumed that I was not doing something necessary to "ack" / "start
the status stage". Actually, the fault was occurring a bit earlier: my
read was failing for the reasons described in my other message of later
yesterday ("Gadgetfs: ep file_operations not changed in deferred config
case") and I'd love to hear any comments about that issue.
> Something to be aware of: not all gadget controller drivers seem to
> handle control-OUT transfers correctly ... especially in the "deferred
> response" mode needed by gadgetfs. You can test control-OUT transfers
> using "usbtest" test case #14; and g_file_storage uses deferred response
> mode, but ISTR not for control-OUT transfers. You might be hitting a
> controller driver (or controller!) bug specific to that combination...
I'm using a Net2280 PCI card. With g_zero, test 14 passes when I run
it as test.sh does:
# ./testusb -D /proc/bus/usb/001/005 -t 14 -c 15000 -s 256 -v 1
unknown speed /proc/bus/usb/001/005
/proc/bus/usb/001/005 test 14, 6.164763 secs
Tests 0-13 pass (with g_zero) when run with default settings.
With gadgetfs and usb.c, tests 0-9 pass, and it hangs on test 10. Is
that expected?
Are you suggesting that I should run testusb against g_file_storage in
order to prove whether the system would support control OUT if my
gadgetfs app needed them?
Phil.
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