On Tue, 11 May 2010, Juergen Beisert wrote: > Hi list, > > we are facing a problem with an EHCI host controller (the one in the i.MX27 > SoC CPU) and an externally connected ISP1504 phy (connected via ULPI). > Connected to this bus is a USB-DVB device. All these devices are connected on > the PCB. The OTG feature of the ISP1504 is not used. > > The EHCI driver comes up, enables the bus and does the enumeration. The > corresponding USB device driver is loaded and tries to initialize its device. > At this point, most of the time it fails with various timeouts. > > We cut the connection (thanks to two 0 ohm resistors in the D+/D- lines) to > the USB-DVB device and tried various other devices: All kind of devices are > failing most of the time. All connections are approved as correct. > > In the next step we inserted our USB scanner into the USB lines to the DVB > device. What we see is: > - RESET and high speed detection handshake > - some data transfers > - a second RESET and a second high speed detection handshake > - some data transfers > - ...and the beginning of a third high speed detection handshake, but > without a previous RESET and without an answer, so the handshake times > out. > - no further communication is possible (the line seems dead). > (note: Same behavior on the bus with the other kind of external devices). > > Any idea why the third high speed detection handshake starts? There is no > RESET and no IDLE state prior its occurrence. Software or hardware issue? For more information on the software side, use a kernel with CONFIG_USB_DEBUG enabled and look at the dmesg log. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
