[U-Boot] Message handling problem in dwc2_otg driver

[Gyorgy Kovesdi]

Hi,

I am using u-boot revision d141e218f3195e305c1521a0d67c81b7cb504b71
(dec 28 2015).
The platform is socfpga cyclone-V.

I connected some different USB devices to my USB port, and some of them
have problems. Especially, if i connect another linux box with CDC mass
storage or ethernet emulation, the device is not detected.

I found that the problem is the NAK message handling: if i connect a
pendrive then no NAK messages returned, but using CDC mass storage
device, there are a lot of them. The problem is that the NAK messages
are not handled at all: if such one received, the driver enters an
endless loop (in file dwc2_otg-hcd.c: see the /* TODO: no endless loop
*/ comment).

AFAIK, the NAK handling is basically necessary for USB communication: i
do not understand how can it work without NAK handling at all. Am i the
only one having NAK messages in this case?

I need some help to resolve the NAK handling here.

Thanx in advance
Gyorgy Kovesdi