On Thursday 10 April 2008, Bryan Wu wrote: > > And for our development board EZKIT548, it can provide 500mA current > > at 5V as it claimed in manual > > with a external regular. So from my point of view, this bug is not > > related with 100mA current limit issue. It's *supposed* to be able to provide that much ... steady state. But the issue here is current spikes that cause the voltage to drop too low. Did you stick a scope on that signal and *verify* that the voltage never dropped below the valid level? > These days I tried hard to workaround this issue, but failed: > > - When VBUS_ERR happens in OTG_A_HOST state and the OTG is in > peripheral mode, I try to start a new session and power on VBUS. > - CONNECT IRQ fired and OTG is switch back to host mode. It needs to re-enumerate at this point, including USB reset. > - In CONNECT IRQ handler, I rescan the musb->endpoint[i].in_qh or > musb->endpoint[i].out_qh. Then resume the urb transfer which was > stopped by the wrong VBUS_ERR mode switch IRQ. or just dequeue the urb > to call off the transfer. > - But the ZiO does not reply anymore. No IRQ from USB hardware. World > keeps silence. That's compatible with the voltage actually dropping too low, so that the peripheral AND host see the session as broken. Sometimes it can help to put a powered hub in between the musb host and the peripheral ... - Dave -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
