Alan Stern wrote: > On Tue, 11 May 2010, Juergen Beisert wrote: > > 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. For the records: Issue seems solved. In this case the flag USB_OTG_EXT_VBUS_INDICATOR was missed when configuring the ULPI from the platform file. Now, the USB communication comes always up after reset and works reliable. Regards, Juergen -- 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
