Re: [Libusb-devel] Synchronous Interrupt support

[Johannes E. <joh...@er...>]

Ahh, that may be the problem.

Not all of the HCDs support multi-packet Interrupt transfers. This is
the code in usb-uhci.c that's tripping it up:

        // INT allows only one packet
        if (urb->transfer_buffer_length > usb_maxpacket (urb->dev, pipe, usb_pipeout (pipe)))
                return -EINVAL;

I can workaround this in libusb.

For now, can you try one write of 8 bytes and then one write of 3 bytes
instead of one write of 11 bytes and see if that works?

JE

On Tue, Mar 18, 2003, David Glance <da...@cs...> wrote:
> That prompted me to look further - I think it has to do with the size, 
> the wMaxPacketSize is 8 and I am passing 7 in the first instance and 11 
> in the second - When I change the second write to 7 it works and fails 
> later - am I write then in thinking that it won't accept anything 
> greater than 8 in this case?
> 
> Johannes Erdfelt wrote:
> 
> >That's good news, but I can't figure out why you would get that error on
> >the second call.
> >
> >Are you using the same buffer, size and endpoint?
> >
> >JE
> >
> >On Mon, Mar 17, 2003, David Glance <da...@cs...> wrote:
> >  
> >
> >>Getting better. I can now write and then read. However, on the second 
> >>write I get this error again:
> >>
> >>USB error: error submitting interrupt URB: Invalid argument
> >>
> >>david
> >>
> >>Johannes Erdfelt wrote:
> >>
> >>    
> >>
> >>>No, all of the HCDs should work fine. I was just curious which one you
> >>>were using since sometimes the return codes in corner cases will differ.
> >>>
> >>>A timeout of 1000 (1 second) sounds fine.
> >>>
> >>>Let me know how it goes when you test again.
> >>>
> >>>JE
> >>>
> >>>On Mon, Mar 17, 2003, David Glance <da...@cs...> wrote:
> >>> 
> >>>
> >>>      
> >>>
> >>>>it is usb-uhci - I can try ohci if you think it would be different. The 
> >>>>timeout is set to 1000 - I will check this out again tonight and let you 
> >>>>know how I get on.
> >>>>
> >>>>Johannes Erdfelt wrote:
> >>>>
> >>>>   
> >>>>
> >>>>        
> >>>>
> >>>>>-103 (on x86 atleast) is -ECONNABORTED. That looks like it's a timeout
> >>>>>condition. Are you using usb-uhci?
> >>>>>
> >>>>>I've checked in some changes that should handle the timeout case better.
> >>>>>
> >>>>>However, you're writing which would mean in this case the device kept on
> >>>>>NAKing, assuming the code in libusb is correct. That's kinda rare, so I
> >>>>>don't think that would happen. What is LINUX_USB_TIMEOUT set to?
> >>>>>
> >>>>>Unfortunately, I don't have easy access to any devices that use
> >>>>>interrupt endpoints, so I'm testing this with a duplicate of this
> >>>>>function but using control transfers.
> >>>>>
> >>>>>JE
> >>>>>
> >>>>>On Mon, Mar 17, 2003, David Glance <da...@cs...> wrote:
> >>>>>
> >>>>>
> >>>>>     
> >>>>>
> >>>>>          
> >>>>>
> >>> 
> >>>
> >>>      
> >>>
> >>
> >>-------------------------------------------------------
> >>This SF.net email is sponsored by:Crypto Challenge is now open! 
> >>Get cracking and register here for some mind boggling fun and 
> >>the chance of winning an Apple iPod:
> >>http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en
> >>_______________________________________________
> >>Libusb-devel mailing list
> >>Lib...@li...
> >>https://lists.sourceforge.net/lists/listinfo/libusb-devel
> >>    
> >>
> >
> >
> >  
> >
>