Hi Simon,
usb_control_message gives you only the faculty to send a control messsage to your device as it is described in the USB specs. So read usb specs v1.1 chapter 9 for more details.
I think you haven't studied your device enough...
Try to look what happens on Windows with SniffUsb...
Does it use Vendor specific control message ?
You should know how the device will send you its response, maybe directly in the buffer or maybe you'll have to send an other control message to get the response in the bufffer (if it uses vendor specific control messages)...
Only you can know how your device behaves...
Eric
-----Original Message-----
From: Jerram, Simon [mailto:[EMAIL PROTECTED]]
Sent: Friday, June 08, 2001 4:35 PM
To: '[EMAIL PROTECTED]'
Subject: [linux-usb-devel] Old USB API
Is there a decent specification available for this? If not...
The Documentation for the URB API referrs to usb_control_msg
as being a converter for the old API, and that it is a good
exapmle on how to use the URB one. To an extent it is,
but simply looking at it without any documentation on how
you're supposed to use it doesn't help. The USB Programming
guide is no help: it merely points to the routine with no
indication of how it works, neither are any of the
drivers I've looked at which are sparse on the code level
documentaion and comments.
OK.
Now I want to send a control msg to which i expect a response.
I use usb_control_msg which completes OK. But I can't tell where
the response goes. Isn't usb_control_msg supposed to be synchronous?
Do I need to use usb_control_msg again with an appropriate buffer to
recieve the response? Or does it get placed in a structure that
I should declared when I sent the control message? Tracing this through
puts me at a dead end: the wake_up point simply seems to return the funtion.
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