Re: [avrdude-dev] [bug #41357] OS X: Avrdude messes with the usb stack?

[Erik Walthinsen]

On 01/27/2014 01:16 PM, Joerg Wunsch wrote:
> I restricted the usb_reset() call to #if defined(__linux__).

This thread went by a week or so ago, but now I'm running into a problem 
caused by this exact line of code.

I have several custom programming jigs based on a USB xmegas that 
implement STK500v2 over USB as well as two CDC serial ports, in a 
composite device.  The problem is that the usb_reset() causes the serial 
port to disappear and reset, which screws up my computer-side software 
pretty badly.

When I remove the usb_reset() line, avrdude continues to work normally, 
and it doesn't reset my CDC devices.  My software happily maintains open 
serial connections and all is well.

Why is usb_reset() there in the first place?  If there's a specific 
error case when it actually helps, it'd be ideal if that case can be 
detected and usb_reset() only called when absolutely necessary.  Either 
way at this point some code comments would probably be in order to 
explain why.

Thanks!