On Apr 6, 2019, at 10:34 AM, Alan Stern 
<st...@rowland.harvard.edu<mailto:st...@rowland.harvard.edu>> wrote:

Why does a 3-KB read cause a failure?  It should work perfectly well.

I thought because the scsi command asked to read 32K.

If I’m incorrect in my assumption, and the chunked read should work,  do you 
have any theories?  I enabled debug spew on xhci, but nothing presented itself 
more than the EOVERFLOW being set when it detects babble.  I would appreciate 
any debug guidance you might be able to offer.  :)

[  179.330047] usb 2-1.3: usbdev_do_ioctl: SUBMITURB
[  179.334761] usb 2-1.3: userurb 0000ffff70001640, ep1 bulk-in, length 3584
[  179.341565] usb 2-1.3: usbdev_do_ioctl: SUBMITURB
[  179.341569] xhci_hcd 0001:01:00.0: Babble error for slot 8 ep 2 on endpoint
[  179.341574] xhci_hcd 0001:01:00.0: // Ding dong!
[  179.341578] xhci_hcd 0001:01:00.0: Giveback URB ffff800073b48a80, len = 
3584, expected = 3584, status = -75
[  179.341581] usb 2-1.3: urb complete

Seth

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