Re: PROBLEM: USB ACM device does not work

[Oliver Neukum]

Am Sonntag, 28. Juni 2009 20:29:26 schrieb Arseniy Lartsev:
> I've got a piece of hardware (this one:
> http://masterkit.ru/main/set.php?num=1153) which acts like an USB ACM
> device and is handeled by the cdc_acm module. /dev/ttyACM0 does appear
> but any attempt to write something to the device with a simple
> "echo something >/dev/ttyACM0" fails with "Invalid argument" error.
>
> The reason is that the driver calls usb_submit_urb in acm_start_wb()
> but doesn't set interval in the urb structure, so it remains zero and
> causes usb_submit_urb to return -EINVAL. Reading from device also does
> not work due to the same problem in acm_rx_tasklet().

This is supposed to write to bulk endpoints. There's no reason interval
would need to be specified. Something is very odd. Please post "lsusb -v".

	Regards
		Oliver

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