All,

I have an unusual request and maybe a linux-usb guru can help me out
here.  I have a device that's been exhibiting weird behavior when it is
assigned a particular USB address.  This shows up when running the
USB-CV 150 enumeration test.  Now, the address isn't *terribly* high, so
plugging in a bunch of devices to bump the addresses up is doable, but I
wonder: is there a better way?

For starters, I suppose I should ask and make sure there's no user-mode
way to do this.  I didn't see anything relevant, but I know next to
nothing about the Linux USB host side (I've only dealt with Gadget)

So, in short, what I'd like to do is somehow force my device to an
address that I choose.  I've been exploring this and tried just adding a
special case into usb_choose_address(), only to find that the host
hasn't pulled the device descriptor information yet (which I'd need to
compare the VID/PID to my failing device - interesting, since Windows
gets the device descriptor before doing anything).  The obvious solution
to that was to try pulling out the device descriptor first but that
appears to fail with ENODEV if you're trying to talk to address zero.

The only other way that comes to mind is to wait until after we've gone
thru usb_set_address and then pulled the device descriptor, and *then*
go thru and give myself the address I want (set device->devnum, clear
the old devnum bit in dev->bus->devmap.devicemap, and set the new bit).

Does anyone have a suggestion of a better way to go about this (even
though under no circumstances do I ever expect any of these hacks to
leave the confines of my cube :)

Thanks for the help,

Alex


******************************************
Alex Sanks
Software Engineer
NetChip Technology, Inc.
Tel:(650)526-1490 x130, Fax:(650)526-1494
http://www.netchip.com
******************************************



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