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?
Regards,
Juergen
--
Pengutronix e.K. | Juergen Beisert |
Linux Solutions for Science and Industry | Phone: +49-8766-939 228 |
Vertretung Sued/Muenchen, Germany | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de/ |
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