[avrdude-dev] Re: [bug #22271] usb_reset in usb_libusb.c not necessary in FreeBSD 6.x

[David Hoerl]

On 11/6/09 4:37 PM, David A. Mellis wrote:
> Follow-up Comment #5, bug #22271 (project avrdude):
>
> In my testing, the usb_reset() is necessary on Mac OS X (10.6 Snow Leopard).
> Otherwise, the upload process will stall for about 25 seconds on the second
> and subsequent attempts.  I suggest that revision 873 be reverted.

David,

Well, I kind of agree. Once I made the change, I too then started seeing 
more failures. But I also noticed that when it succeeds, its also a bit 
slow.

As I posted the other day, what I ended up doing is installing 
libusb.1.0, and libcompat.0.1. The current libusb.0.1 is quite old and 
will itself never be updated. The combination of the new library and a 
glue library fix a lot of issues (according to authors).

Even then, avrdude was running slowly. I actually spend a fair amount of 
time putting in debugging command to find out why. It turned out its in 
the two library calls to get busses and devices.

Well, it seems Apple suspends unused devices (like iSights), and the 
current libusb.1.0 tries to wake them, get their info, and then put them 
back to sleep. The code that does this was easily turned off, so I build 
a special version of libusb-1.0, and now avrdude is running MUCH faster 
than it ever did with the old libusb.0.1

My point in all this is that you can work with avrdude the way it is, do 
the same things I did (take less than an hour), and have a much faster 
and more reliable system.


That said, if you want it back, well, what I would then suggest is that 
I add a new flag to avrdude that forces a usb reset - current systems 
would get it, others could request it. This would then allows 
FreeBSD/Mac people use either the new or the old library.


David

PS: should avrdude migrate to the new usblib.1.0 someday?