Re: [avrdude-dev] [bug #40831] LUFA AVRISP-MKII fails with avrdude 6.0.1

[Dean Camera]

Hi Colin,

Yes, of course ultimately I'd love to get AVRDUDE out-of-the-box 
compatible with my programmer. However, I realize Joerg et. al. may feel 
differently, since my firmware is only a clone of the real thing, and 
limited by the hardware platform that I have designed it for. I don't 
really expect Joerg or the other developers to put in extra effort to 
make my clone firmware work correctly.

That said, I think we have the potential for some quick fixes here that 
shouldn't impact users of the real-deal.

The first is the fixing of the endpoint selection, which currently 
blocks all users of AVRDUDE from using my clone programmer completely, 
as the workaround I have for the second incompatibility involves using 
different endpoint addresses to the real units, which AVRDUDE-HEAD 
ignores. If we can fix the endpoint detection code, users will be able 
to use the "libUSB compatibility mode" firmware I built to work around 
the second issue.

The second issue is the serial drain code in AVRDude tripping up my 
limited bidirectional endpoint code. Turning this code off eliminates 
the need for my compatibility mode firmware, and makes my clone 
completely out-of-the-box AVRDUDE compatible. However, that may have 
ramifications I am not aware of, so Joerg would need to weigh in.

Cheers!
- Dean

On 15/09/2014 9:06 AM, Colin O'Flynn wrote:
> Hi Dean/Joerg,
>
> Keeping my reply on the list & not bugtracker as not directly related to
> that bug:
>
> Do you think it's worth fixing the issue forcing the separate endpoints?
> AFAIK the issue is triggered by a call to usbdev_drain() which might be
> possible to work around (read: just disable for avr-isp2).
>
> I only ask as if this is fixed it might add another complication to the
> system, and I don't know if it would become worth making two separate
> AVR-ISPmk2 programmers at that point. One has the 'libusb' fixes and assumes
> the two separate endpoints, (i.e. called avrisp2lufa or whatever), one
> always assumes endpoints are as in Atmel AVRISP-MK2.
>
> I assume it would be possible to differentiate between the 3 programmers and
> enable the correct code (i.e.: Atmel AVR-ISPMK2, LUFA AVR-ISPMK2 in
> AVRStudio Mode, LUFA AVR-ISPMK2 in LIBUSB Mode). But it might become a
> ungainly/difficult to maintain into the future, and ultimately be easier at
> some point in time say screw it to the users, and make them specify exactly
> what they want.
>
> Regards,
>
>    -Colin O'Flynn
>
>
>
> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden On Behalf Of Dean
> Camera
> Sent: September-13-14 4:54 AM
> To: Dean Camera; Larry Viesse; Joerg Wunsch; Ron Snijders;
> address@hidden
> Subject: [avrdude-dev] [bug #40831] LUFA AVRISP-MKII fails with avrdude
> 6.0.1
>
> Follow-up Comment #4, bug #40831 (project avrdude):
>
> Since there is already a read endpoint fallback in usb_libusb.c:
>
> if (fd->usb.rep == 0)
>                         {
>                           avrdude_message(MSG_INFO, "%s: usbdev_open():
> cannot find a read endpoint, using 0x%02xn",
>                                            progname,
> USBDEV_BULK_EP_READ_MKII);
>                           fd->usb.rep = USBDEV_BULK_EP_READ_MKII;
>                         }
>
> Should we either set the usb.rep value to 0 in the upper tool layer, or
> explicitly zero it out in the usb layer?
>
>      _______________________________________________________
>
> Reply to this item at:
>
>    <http://savannah.nongnu.org/bugs/?40831>
>
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